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linux/arch/mips/kvm/kvm_mips_emul.c

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KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* KVM/MIPS: Instruction/Exception emulation
*
* Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved.
* Authors: Sanjay Lal <sanjayl@kymasys.com>
*/
#include <linux/errno.h>
#include <linux/err.h>
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
#include <linux/ktime.h>
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
#include <linux/kvm_host.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/bootmem.h>
#include <linux/random.h>
#include <asm/page.h>
#include <asm/cacheflush.h>
#include <asm/cpu-info.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
#include <asm/inst.h>
#undef CONFIG_MIPS_MT
#include <asm/r4kcache.h>
#define CONFIG_MIPS_MT
#include "kvm_mips_opcode.h"
#include "kvm_mips_int.h"
#include "kvm_mips_comm.h"
#include "trace.h"
/*
* Compute the return address and do emulate branch simulation, if required.
* This function should be called only in branch delay slot active.
*/
unsigned long kvm_compute_return_epc(struct kvm_vcpu *vcpu,
unsigned long instpc)
{
unsigned int dspcontrol;
union mips_instruction insn;
struct kvm_vcpu_arch *arch = &vcpu->arch;
long epc = instpc;
long nextpc = KVM_INVALID_INST;
if (epc & 3)
goto unaligned;
/*
* Read the instruction
*/
insn.word = kvm_get_inst((uint32_t *) epc, vcpu);
if (insn.word == KVM_INVALID_INST)
return KVM_INVALID_INST;
switch (insn.i_format.opcode) {
/*
* jr and jalr are in r_format format.
*/
case spec_op:
switch (insn.r_format.func) {
case jalr_op:
arch->gprs[insn.r_format.rd] = epc + 8;
/* Fall through */
case jr_op:
nextpc = arch->gprs[insn.r_format.rs];
break;
}
break;
/*
* This group contains:
* bltz_op, bgez_op, bltzl_op, bgezl_op,
* bltzal_op, bgezal_op, bltzall_op, bgezall_op.
*/
case bcond_op:
switch (insn.i_format.rt) {
case bltz_op:
case bltzl_op:
if ((long)arch->gprs[insn.i_format.rs] < 0)
epc = epc + 4 + (insn.i_format.simmediate << 2);
else
epc += 8;
nextpc = epc;
break;
case bgez_op:
case bgezl_op:
if ((long)arch->gprs[insn.i_format.rs] >= 0)
epc = epc + 4 + (insn.i_format.simmediate << 2);
else
epc += 8;
nextpc = epc;
break;
case bltzal_op:
case bltzall_op:
arch->gprs[31] = epc + 8;
if ((long)arch->gprs[insn.i_format.rs] < 0)
epc = epc + 4 + (insn.i_format.simmediate << 2);
else
epc += 8;
nextpc = epc;
break;
case bgezal_op:
case bgezall_op:
arch->gprs[31] = epc + 8;
if ((long)arch->gprs[insn.i_format.rs] >= 0)
epc = epc + 4 + (insn.i_format.simmediate << 2);
else
epc += 8;
nextpc = epc;
break;
case bposge32_op:
if (!cpu_has_dsp)
goto sigill;
dspcontrol = rddsp(0x01);
if (dspcontrol >= 32) {
epc = epc + 4 + (insn.i_format.simmediate << 2);
} else
epc += 8;
nextpc = epc;
break;
}
break;
/*
* These are unconditional and in j_format.
*/
case jal_op:
arch->gprs[31] = instpc + 8;
case j_op:
epc += 4;
epc >>= 28;
epc <<= 28;
epc |= (insn.j_format.target << 2);
nextpc = epc;
break;
/*
* These are conditional and in i_format.
*/
case beq_op:
case beql_op:
if (arch->gprs[insn.i_format.rs] ==
arch->gprs[insn.i_format.rt])
epc = epc + 4 + (insn.i_format.simmediate << 2);
else
epc += 8;
nextpc = epc;
break;
case bne_op:
case bnel_op:
if (arch->gprs[insn.i_format.rs] !=
arch->gprs[insn.i_format.rt])
epc = epc + 4 + (insn.i_format.simmediate << 2);
else
epc += 8;
nextpc = epc;
break;
case blez_op: /* not really i_format */
case blezl_op:
/* rt field assumed to be zero */
if ((long)arch->gprs[insn.i_format.rs] <= 0)
epc = epc + 4 + (insn.i_format.simmediate << 2);
else
epc += 8;
nextpc = epc;
break;
case bgtz_op:
case bgtzl_op:
/* rt field assumed to be zero */
if ((long)arch->gprs[insn.i_format.rs] > 0)
epc = epc + 4 + (insn.i_format.simmediate << 2);
else
epc += 8;
nextpc = epc;
break;
/*
* And now the FPA/cp1 branch instructions.
*/
case cop1_op:
printk("%s: unsupported cop1_op\n", __func__);
break;
}
return nextpc;
unaligned:
printk("%s: unaligned epc\n", __func__);
return nextpc;
sigill:
printk("%s: DSP branch but not DSP ASE\n", __func__);
return nextpc;
}
enum emulation_result update_pc(struct kvm_vcpu *vcpu, uint32_t cause)
{
unsigned long branch_pc;
enum emulation_result er = EMULATE_DONE;
if (cause & CAUSEF_BD) {
branch_pc = kvm_compute_return_epc(vcpu, vcpu->arch.pc);
if (branch_pc == KVM_INVALID_INST) {
er = EMULATE_FAIL;
} else {
vcpu->arch.pc = branch_pc;
kvm_debug("BD update_pc(): New PC: %#lx\n", vcpu->arch.pc);
}
} else
vcpu->arch.pc += 4;
kvm_debug("update_pc(): New PC: %#lx\n", vcpu->arch.pc);
return er;
}
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
/**
* kvm_mips_count_disabled() - Find whether the CP0_Count timer is disabled.
* @vcpu: Virtual CPU.
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
*
MIPS: KVM: Add master disable count interface Expose two new virtual registers to userland via the KVM_{GET,SET}_ONE_REG ioctls. KVM_REG_MIPS_COUNT_CTL is for timer configuration fields and just contains a master disable count bit. This can be used by userland to freeze the timer in order to read a consistent state from the timer count value and timer interrupt pending bit. This cannot be done with the CP0_Cause.DC bit because the timer interrupt pending bit (TI) is also in CP0_Cause so it would be impossible to stop the timer without also risking a race with an hrtimer interrupt and having to explicitly check whether an interrupt should have occurred. When the timer is re-enabled it resumes without losing time, i.e. the CP0_Count value jumps to what it would have been had the timer not been disabled, which would also be impossible to do from userland with CP0_Cause.DC. The timer interrupt also cannot be lost, i.e. if a timer interrupt would have occurred had the timer not been disabled it is queued when the timer is re-enabled. This works by storing the nanosecond monotonic time when the master disable is set, and using it for various operations instead of the current monotonic time (e.g. when recalculating the bias when the CP0_Count is set), until the master disable is cleared again, i.e. the timer state is read/written as it would have been at that time. This state is exposed to userland via the read-only KVM_REG_MIPS_COUNT_RESUME virtual register so that userland can determine the exact time the master disable took effect. This should allow userland to atomically save the state of the timer, and later restore it. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: David Daney <david.daney@cavium.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:37 +00:00
* Returns: 1 if the CP0_Count timer is disabled by either the guest
* CP0_Cause.DC bit or the count_ctl.DC bit.
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
* 0 otherwise (in which case CP0_Count timer is running).
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
*/
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
static inline int kvm_mips_count_disabled(struct kvm_vcpu *vcpu)
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
MIPS: KVM: Add master disable count interface Expose two new virtual registers to userland via the KVM_{GET,SET}_ONE_REG ioctls. KVM_REG_MIPS_COUNT_CTL is for timer configuration fields and just contains a master disable count bit. This can be used by userland to freeze the timer in order to read a consistent state from the timer count value and timer interrupt pending bit. This cannot be done with the CP0_Cause.DC bit because the timer interrupt pending bit (TI) is also in CP0_Cause so it would be impossible to stop the timer without also risking a race with an hrtimer interrupt and having to explicitly check whether an interrupt should have occurred. When the timer is re-enabled it resumes without losing time, i.e. the CP0_Count value jumps to what it would have been had the timer not been disabled, which would also be impossible to do from userland with CP0_Cause.DC. The timer interrupt also cannot be lost, i.e. if a timer interrupt would have occurred had the timer not been disabled it is queued when the timer is re-enabled. This works by storing the nanosecond monotonic time when the master disable is set, and using it for various operations instead of the current monotonic time (e.g. when recalculating the bias when the CP0_Count is set), until the master disable is cleared again, i.e. the timer state is read/written as it would have been at that time. This state is exposed to userland via the read-only KVM_REG_MIPS_COUNT_RESUME virtual register so that userland can determine the exact time the master disable took effect. This should allow userland to atomically save the state of the timer, and later restore it. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: David Daney <david.daney@cavium.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:37 +00:00
return (vcpu->arch.count_ctl & KVM_REG_MIPS_COUNT_CTL_DC) ||
(kvm_read_c0_guest_cause(cop0) & CAUSEF_DC);
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
}
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
/**
* kvm_mips_ktime_to_count() - Scale ktime_t to a 32-bit count.
*
* Caches the dynamic nanosecond bias in vcpu->arch.count_dyn_bias.
*
* Assumes !kvm_mips_count_disabled(@vcpu) (guest CP0_Count timer is running).
*/
static uint32_t kvm_mips_ktime_to_count(struct kvm_vcpu *vcpu, ktime_t now)
{
s64 now_ns, periods;
u64 delta;
now_ns = ktime_to_ns(now);
delta = now_ns + vcpu->arch.count_dyn_bias;
if (delta >= vcpu->arch.count_period) {
/* If delta is out of safe range the bias needs adjusting */
periods = div64_s64(now_ns, vcpu->arch.count_period);
vcpu->arch.count_dyn_bias = -periods * vcpu->arch.count_period;
/* Recalculate delta with new bias */
delta = now_ns + vcpu->arch.count_dyn_bias;
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
}
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
/*
* We've ensured that:
* delta < count_period
*
* Therefore the intermediate delta*count_hz will never overflow since
* at the boundary condition:
* delta = count_period
* delta = NSEC_PER_SEC * 2^32 / count_hz
* delta * count_hz = NSEC_PER_SEC * 2^32
*/
return div_u64(delta * vcpu->arch.count_hz, NSEC_PER_SEC);
}
MIPS: KVM: Add master disable count interface Expose two new virtual registers to userland via the KVM_{GET,SET}_ONE_REG ioctls. KVM_REG_MIPS_COUNT_CTL is for timer configuration fields and just contains a master disable count bit. This can be used by userland to freeze the timer in order to read a consistent state from the timer count value and timer interrupt pending bit. This cannot be done with the CP0_Cause.DC bit because the timer interrupt pending bit (TI) is also in CP0_Cause so it would be impossible to stop the timer without also risking a race with an hrtimer interrupt and having to explicitly check whether an interrupt should have occurred. When the timer is re-enabled it resumes without losing time, i.e. the CP0_Count value jumps to what it would have been had the timer not been disabled, which would also be impossible to do from userland with CP0_Cause.DC. The timer interrupt also cannot be lost, i.e. if a timer interrupt would have occurred had the timer not been disabled it is queued when the timer is re-enabled. This works by storing the nanosecond monotonic time when the master disable is set, and using it for various operations instead of the current monotonic time (e.g. when recalculating the bias when the CP0_Count is set), until the master disable is cleared again, i.e. the timer state is read/written as it would have been at that time. This state is exposed to userland via the read-only KVM_REG_MIPS_COUNT_RESUME virtual register so that userland can determine the exact time the master disable took effect. This should allow userland to atomically save the state of the timer, and later restore it. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: David Daney <david.daney@cavium.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:37 +00:00
/**
* kvm_mips_count_time() - Get effective current time.
* @vcpu: Virtual CPU.
*
* Get effective monotonic ktime. This is usually a straightforward ktime_get(),
* except when the master disable bit is set in count_ctl, in which case it is
* count_resume, i.e. the time that the count was disabled.
*
* Returns: Effective monotonic ktime for CP0_Count.
*/
static inline ktime_t kvm_mips_count_time(struct kvm_vcpu *vcpu)
{
if (unlikely(vcpu->arch.count_ctl & KVM_REG_MIPS_COUNT_CTL_DC))
return vcpu->arch.count_resume;
return ktime_get();
}
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
/**
* kvm_mips_read_count_running() - Read the current count value as if running.
* @vcpu: Virtual CPU.
* @now: Kernel time to read CP0_Count at.
*
* Returns the current guest CP0_Count register at time @now and handles if the
* timer interrupt is pending and hasn't been handled yet.
*
* Returns: The current value of the guest CP0_Count register.
*/
static uint32_t kvm_mips_read_count_running(struct kvm_vcpu *vcpu, ktime_t now)
{
ktime_t expires;
int running;
/* Is the hrtimer pending? */
expires = hrtimer_get_expires(&vcpu->arch.comparecount_timer);
if (ktime_compare(now, expires) >= 0) {
/*
* Cancel it while we handle it so there's no chance of
* interference with the timeout handler.
*/
running = hrtimer_cancel(&vcpu->arch.comparecount_timer);
/* Nothing should be waiting on the timeout */
kvm_mips_callbacks->queue_timer_int(vcpu);
/*
* Restart the timer if it was running based on the expiry time
* we read, so that we don't push it back 2 periods.
*/
if (running) {
expires = ktime_add_ns(expires,
vcpu->arch.count_period);
hrtimer_start(&vcpu->arch.comparecount_timer, expires,
HRTIMER_MODE_ABS);
}
}
/* Return the biased and scaled guest CP0_Count */
return vcpu->arch.count_bias + kvm_mips_ktime_to_count(vcpu, now);
}
/**
* kvm_mips_read_count() - Read the current count value.
* @vcpu: Virtual CPU.
*
* Read the current guest CP0_Count value, taking into account whether the timer
* is stopped.
*
* Returns: The current guest CP0_Count value.
*/
uint32_t kvm_mips_read_count(struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
/* If count disabled just read static copy of count */
if (kvm_mips_count_disabled(vcpu))
return kvm_read_c0_guest_count(cop0);
return kvm_mips_read_count_running(vcpu, ktime_get());
}
/**
* kvm_mips_freeze_hrtimer() - Safely stop the hrtimer.
* @vcpu: Virtual CPU.
* @count: Output pointer for CP0_Count value at point of freeze.
*
* Freeze the hrtimer safely and return both the ktime and the CP0_Count value
* at the point it was frozen. It is guaranteed that any pending interrupts at
* the point it was frozen are handled, and none after that point.
*
* This is useful where the time/CP0_Count is needed in the calculation of the
* new parameters.
*
* Assumes !kvm_mips_count_disabled(@vcpu) (guest CP0_Count timer is running).
*
* Returns: The ktime at the point of freeze.
*/
static ktime_t kvm_mips_freeze_hrtimer(struct kvm_vcpu *vcpu,
uint32_t *count)
{
ktime_t now;
/* stop hrtimer before finding time */
hrtimer_cancel(&vcpu->arch.comparecount_timer);
now = ktime_get();
/* find count at this point and handle pending hrtimer */
*count = kvm_mips_read_count_running(vcpu, now);
return now;
}
/**
* kvm_mips_resume_hrtimer() - Resume hrtimer, updating expiry.
* @vcpu: Virtual CPU.
* @now: ktime at point of resume.
* @count: CP0_Count at point of resume.
*
* Resumes the timer and updates the timer expiry based on @now and @count.
* This can be used in conjunction with kvm_mips_freeze_timer() when timer
* parameters need to be changed.
*
* It is guaranteed that a timer interrupt immediately after resume will be
* handled, but not if CP_Compare is exactly at @count. That case is already
* handled by kvm_mips_freeze_timer().
*
* Assumes !kvm_mips_count_disabled(@vcpu) (guest CP0_Count timer is running).
*/
static void kvm_mips_resume_hrtimer(struct kvm_vcpu *vcpu,
ktime_t now, uint32_t count)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
uint32_t compare;
u64 delta;
ktime_t expire;
/* Calculate timeout (wrap 0 to 2^32) */
compare = kvm_read_c0_guest_compare(cop0);
delta = (u64)(uint32_t)(compare - count - 1) + 1;
delta = div_u64(delta * NSEC_PER_SEC, vcpu->arch.count_hz);
expire = ktime_add_ns(now, delta);
/* Update hrtimer to use new timeout */
hrtimer_cancel(&vcpu->arch.comparecount_timer);
hrtimer_start(&vcpu->arch.comparecount_timer, expire, HRTIMER_MODE_ABS);
}
/**
* kvm_mips_update_hrtimer() - Update next expiry time of hrtimer.
* @vcpu: Virtual CPU.
*
* Recalculates and updates the expiry time of the hrtimer. This can be used
* after timer parameters have been altered which do not depend on the time that
* the change occurs (in those cases kvm_mips_freeze_hrtimer() and
* kvm_mips_resume_hrtimer() are used directly).
*
* It is guaranteed that no timer interrupts will be lost in the process.
*
* Assumes !kvm_mips_count_disabled(@vcpu) (guest CP0_Count timer is running).
*/
static void kvm_mips_update_hrtimer(struct kvm_vcpu *vcpu)
{
ktime_t now;
uint32_t count;
/*
* freeze_hrtimer takes care of a timer interrupts <= count, and
* resume_hrtimer the hrtimer takes care of a timer interrupts > count.
*/
now = kvm_mips_freeze_hrtimer(vcpu, &count);
kvm_mips_resume_hrtimer(vcpu, now, count);
}
/**
* kvm_mips_write_count() - Modify the count and update timer.
* @vcpu: Virtual CPU.
* @count: Guest CP0_Count value to set.
*
* Sets the CP0_Count value and updates the timer accordingly.
*/
void kvm_mips_write_count(struct kvm_vcpu *vcpu, uint32_t count)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
ktime_t now;
/* Calculate bias */
MIPS: KVM: Add master disable count interface Expose two new virtual registers to userland via the KVM_{GET,SET}_ONE_REG ioctls. KVM_REG_MIPS_COUNT_CTL is for timer configuration fields and just contains a master disable count bit. This can be used by userland to freeze the timer in order to read a consistent state from the timer count value and timer interrupt pending bit. This cannot be done with the CP0_Cause.DC bit because the timer interrupt pending bit (TI) is also in CP0_Cause so it would be impossible to stop the timer without also risking a race with an hrtimer interrupt and having to explicitly check whether an interrupt should have occurred. When the timer is re-enabled it resumes without losing time, i.e. the CP0_Count value jumps to what it would have been had the timer not been disabled, which would also be impossible to do from userland with CP0_Cause.DC. The timer interrupt also cannot be lost, i.e. if a timer interrupt would have occurred had the timer not been disabled it is queued when the timer is re-enabled. This works by storing the nanosecond monotonic time when the master disable is set, and using it for various operations instead of the current monotonic time (e.g. when recalculating the bias when the CP0_Count is set), until the master disable is cleared again, i.e. the timer state is read/written as it would have been at that time. This state is exposed to userland via the read-only KVM_REG_MIPS_COUNT_RESUME virtual register so that userland can determine the exact time the master disable took effect. This should allow userland to atomically save the state of the timer, and later restore it. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: David Daney <david.daney@cavium.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:37 +00:00
now = kvm_mips_count_time(vcpu);
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
vcpu->arch.count_bias = count - kvm_mips_ktime_to_count(vcpu, now);
if (kvm_mips_count_disabled(vcpu))
/* The timer's disabled, adjust the static count */
kvm_write_c0_guest_count(cop0, count);
else
/* Update timeout */
kvm_mips_resume_hrtimer(vcpu, now, count);
}
/**
* kvm_mips_init_count() - Initialise timer.
* @vcpu: Virtual CPU.
*
* Initialise the timer to a sensible frequency, namely 100MHz, zero it, and set
* it going if it's enabled.
*/
void kvm_mips_init_count(struct kvm_vcpu *vcpu)
{
/* 100 MHz */
vcpu->arch.count_hz = 100*1000*1000;
vcpu->arch.count_period = div_u64((u64)NSEC_PER_SEC << 32,
vcpu->arch.count_hz);
vcpu->arch.count_dyn_bias = 0;
/* Starting at 0 */
kvm_mips_write_count(vcpu, 0);
}
MIPS: KVM: Add count frequency KVM register Expose the KVM guest CP0_Count frequency to userland via a new KVM_REG_MIPS_COUNT_HZ register accessible with the KVM_{GET,SET}_ONE_REG ioctls. When the frequency is altered the bias is adjusted such that the guest CP0_Count doesn't jump discontinuously or lose any timer interrupts. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: David Daney <david.daney@cavium.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:38 +00:00
/**
* kvm_mips_set_count_hz() - Update the frequency of the timer.
* @vcpu: Virtual CPU.
* @count_hz: Frequency of CP0_Count timer in Hz.
*
* Change the frequency of the CP0_Count timer. This is done atomically so that
* CP0_Count is continuous and no timer interrupt is lost.
*
* Returns: -EINVAL if @count_hz is out of range.
* 0 on success.
*/
int kvm_mips_set_count_hz(struct kvm_vcpu *vcpu, s64 count_hz)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
int dc;
ktime_t now;
u32 count;
/* ensure the frequency is in a sensible range... */
if (count_hz <= 0 || count_hz > NSEC_PER_SEC)
return -EINVAL;
/* ... and has actually changed */
if (vcpu->arch.count_hz == count_hz)
return 0;
/* Safely freeze timer so we can keep it continuous */
dc = kvm_mips_count_disabled(vcpu);
if (dc) {
now = kvm_mips_count_time(vcpu);
count = kvm_read_c0_guest_count(cop0);
} else {
now = kvm_mips_freeze_hrtimer(vcpu, &count);
}
/* Update the frequency */
vcpu->arch.count_hz = count_hz;
vcpu->arch.count_period = div_u64((u64)NSEC_PER_SEC << 32, count_hz);
vcpu->arch.count_dyn_bias = 0;
/* Calculate adjusted bias so dynamic count is unchanged */
vcpu->arch.count_bias = count - kvm_mips_ktime_to_count(vcpu, now);
/* Update and resume hrtimer */
if (!dc)
kvm_mips_resume_hrtimer(vcpu, now, count);
return 0;
}
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
/**
* kvm_mips_write_compare() - Modify compare and update timer.
* @vcpu: Virtual CPU.
* @compare: New CP0_Compare value.
*
* Update CP0_Compare to a new value and update the timeout.
*/
void kvm_mips_write_compare(struct kvm_vcpu *vcpu, uint32_t compare)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
/* if unchanged, must just be an ack */
if (kvm_read_c0_guest_compare(cop0) == compare)
return;
/* Update compare */
kvm_write_c0_guest_compare(cop0, compare);
/* Update timeout if count enabled */
if (!kvm_mips_count_disabled(vcpu))
kvm_mips_update_hrtimer(vcpu);
}
/**
* kvm_mips_count_disable() - Disable count.
* @vcpu: Virtual CPU.
*
* Disable the CP0_Count timer. A timer interrupt on or before the final stop
* time will be handled but not after.
*
MIPS: KVM: Add master disable count interface Expose two new virtual registers to userland via the KVM_{GET,SET}_ONE_REG ioctls. KVM_REG_MIPS_COUNT_CTL is for timer configuration fields and just contains a master disable count bit. This can be used by userland to freeze the timer in order to read a consistent state from the timer count value and timer interrupt pending bit. This cannot be done with the CP0_Cause.DC bit because the timer interrupt pending bit (TI) is also in CP0_Cause so it would be impossible to stop the timer without also risking a race with an hrtimer interrupt and having to explicitly check whether an interrupt should have occurred. When the timer is re-enabled it resumes without losing time, i.e. the CP0_Count value jumps to what it would have been had the timer not been disabled, which would also be impossible to do from userland with CP0_Cause.DC. The timer interrupt also cannot be lost, i.e. if a timer interrupt would have occurred had the timer not been disabled it is queued when the timer is re-enabled. This works by storing the nanosecond monotonic time when the master disable is set, and using it for various operations instead of the current monotonic time (e.g. when recalculating the bias when the CP0_Count is set), until the master disable is cleared again, i.e. the timer state is read/written as it would have been at that time. This state is exposed to userland via the read-only KVM_REG_MIPS_COUNT_RESUME virtual register so that userland can determine the exact time the master disable took effect. This should allow userland to atomically save the state of the timer, and later restore it. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: David Daney <david.daney@cavium.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:37 +00:00
* Assumes CP0_Count was previously enabled but now Guest.CP0_Cause.DC or
* count_ctl.DC has been set (count disabled).
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
*
* Returns: The time that the timer was stopped.
*/
static ktime_t kvm_mips_count_disable(struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
uint32_t count;
ktime_t now;
/* Stop hrtimer */
hrtimer_cancel(&vcpu->arch.comparecount_timer);
/* Set the static count from the dynamic count, handling pending TI */
now = ktime_get();
count = kvm_mips_read_count_running(vcpu, now);
kvm_write_c0_guest_count(cop0, count);
return now;
}
/**
* kvm_mips_count_disable_cause() - Disable count using CP0_Cause.DC.
* @vcpu: Virtual CPU.
*
* Disable the CP0_Count timer and set CP0_Cause.DC. A timer interrupt on or
MIPS: KVM: Add master disable count interface Expose two new virtual registers to userland via the KVM_{GET,SET}_ONE_REG ioctls. KVM_REG_MIPS_COUNT_CTL is for timer configuration fields and just contains a master disable count bit. This can be used by userland to freeze the timer in order to read a consistent state from the timer count value and timer interrupt pending bit. This cannot be done with the CP0_Cause.DC bit because the timer interrupt pending bit (TI) is also in CP0_Cause so it would be impossible to stop the timer without also risking a race with an hrtimer interrupt and having to explicitly check whether an interrupt should have occurred. When the timer is re-enabled it resumes without losing time, i.e. the CP0_Count value jumps to what it would have been had the timer not been disabled, which would also be impossible to do from userland with CP0_Cause.DC. The timer interrupt also cannot be lost, i.e. if a timer interrupt would have occurred had the timer not been disabled it is queued when the timer is re-enabled. This works by storing the nanosecond monotonic time when the master disable is set, and using it for various operations instead of the current monotonic time (e.g. when recalculating the bias when the CP0_Count is set), until the master disable is cleared again, i.e. the timer state is read/written as it would have been at that time. This state is exposed to userland via the read-only KVM_REG_MIPS_COUNT_RESUME virtual register so that userland can determine the exact time the master disable took effect. This should allow userland to atomically save the state of the timer, and later restore it. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: David Daney <david.daney@cavium.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:37 +00:00
* before the final stop time will be handled if the timer isn't disabled by
* count_ctl.DC, but not after.
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
*
* Assumes CP0_Cause.DC is clear (count enabled).
*/
void kvm_mips_count_disable_cause(struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
kvm_set_c0_guest_cause(cop0, CAUSEF_DC);
MIPS: KVM: Add master disable count interface Expose two new virtual registers to userland via the KVM_{GET,SET}_ONE_REG ioctls. KVM_REG_MIPS_COUNT_CTL is for timer configuration fields and just contains a master disable count bit. This can be used by userland to freeze the timer in order to read a consistent state from the timer count value and timer interrupt pending bit. This cannot be done with the CP0_Cause.DC bit because the timer interrupt pending bit (TI) is also in CP0_Cause so it would be impossible to stop the timer without also risking a race with an hrtimer interrupt and having to explicitly check whether an interrupt should have occurred. When the timer is re-enabled it resumes without losing time, i.e. the CP0_Count value jumps to what it would have been had the timer not been disabled, which would also be impossible to do from userland with CP0_Cause.DC. The timer interrupt also cannot be lost, i.e. if a timer interrupt would have occurred had the timer not been disabled it is queued when the timer is re-enabled. This works by storing the nanosecond monotonic time when the master disable is set, and using it for various operations instead of the current monotonic time (e.g. when recalculating the bias when the CP0_Count is set), until the master disable is cleared again, i.e. the timer state is read/written as it would have been at that time. This state is exposed to userland via the read-only KVM_REG_MIPS_COUNT_RESUME virtual register so that userland can determine the exact time the master disable took effect. This should allow userland to atomically save the state of the timer, and later restore it. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: David Daney <david.daney@cavium.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:37 +00:00
if (!(vcpu->arch.count_ctl & KVM_REG_MIPS_COUNT_CTL_DC))
kvm_mips_count_disable(vcpu);
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
}
/**
* kvm_mips_count_enable_cause() - Enable count using CP0_Cause.DC.
* @vcpu: Virtual CPU.
*
* Enable the CP0_Count timer and clear CP0_Cause.DC. A timer interrupt after
MIPS: KVM: Add master disable count interface Expose two new virtual registers to userland via the KVM_{GET,SET}_ONE_REG ioctls. KVM_REG_MIPS_COUNT_CTL is for timer configuration fields and just contains a master disable count bit. This can be used by userland to freeze the timer in order to read a consistent state from the timer count value and timer interrupt pending bit. This cannot be done with the CP0_Cause.DC bit because the timer interrupt pending bit (TI) is also in CP0_Cause so it would be impossible to stop the timer without also risking a race with an hrtimer interrupt and having to explicitly check whether an interrupt should have occurred. When the timer is re-enabled it resumes without losing time, i.e. the CP0_Count value jumps to what it would have been had the timer not been disabled, which would also be impossible to do from userland with CP0_Cause.DC. The timer interrupt also cannot be lost, i.e. if a timer interrupt would have occurred had the timer not been disabled it is queued when the timer is re-enabled. This works by storing the nanosecond monotonic time when the master disable is set, and using it for various operations instead of the current monotonic time (e.g. when recalculating the bias when the CP0_Count is set), until the master disable is cleared again, i.e. the timer state is read/written as it would have been at that time. This state is exposed to userland via the read-only KVM_REG_MIPS_COUNT_RESUME virtual register so that userland can determine the exact time the master disable took effect. This should allow userland to atomically save the state of the timer, and later restore it. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: David Daney <david.daney@cavium.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:37 +00:00
* the start time will be handled if the timer isn't disabled by count_ctl.DC,
* potentially before even returning, so the caller should be careful with
* ordering of CP0_Cause modifications so as not to lose it.
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
*
* Assumes CP0_Cause.DC is set (count disabled).
*/
void kvm_mips_count_enable_cause(struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
uint32_t count;
kvm_clear_c0_guest_cause(cop0, CAUSEF_DC);
/*
* Set the dynamic count to match the static count.
MIPS: KVM: Add master disable count interface Expose two new virtual registers to userland via the KVM_{GET,SET}_ONE_REG ioctls. KVM_REG_MIPS_COUNT_CTL is for timer configuration fields and just contains a master disable count bit. This can be used by userland to freeze the timer in order to read a consistent state from the timer count value and timer interrupt pending bit. This cannot be done with the CP0_Cause.DC bit because the timer interrupt pending bit (TI) is also in CP0_Cause so it would be impossible to stop the timer without also risking a race with an hrtimer interrupt and having to explicitly check whether an interrupt should have occurred. When the timer is re-enabled it resumes without losing time, i.e. the CP0_Count value jumps to what it would have been had the timer not been disabled, which would also be impossible to do from userland with CP0_Cause.DC. The timer interrupt also cannot be lost, i.e. if a timer interrupt would have occurred had the timer not been disabled it is queued when the timer is re-enabled. This works by storing the nanosecond monotonic time when the master disable is set, and using it for various operations instead of the current monotonic time (e.g. when recalculating the bias when the CP0_Count is set), until the master disable is cleared again, i.e. the timer state is read/written as it would have been at that time. This state is exposed to userland via the read-only KVM_REG_MIPS_COUNT_RESUME virtual register so that userland can determine the exact time the master disable took effect. This should allow userland to atomically save the state of the timer, and later restore it. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: David Daney <david.daney@cavium.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:37 +00:00
* This starts the hrtimer if count_ctl.DC allows it.
* Otherwise it conveniently updates the biases.
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
*/
count = kvm_read_c0_guest_count(cop0);
kvm_mips_write_count(vcpu, count);
}
MIPS: KVM: Add master disable count interface Expose two new virtual registers to userland via the KVM_{GET,SET}_ONE_REG ioctls. KVM_REG_MIPS_COUNT_CTL is for timer configuration fields and just contains a master disable count bit. This can be used by userland to freeze the timer in order to read a consistent state from the timer count value and timer interrupt pending bit. This cannot be done with the CP0_Cause.DC bit because the timer interrupt pending bit (TI) is also in CP0_Cause so it would be impossible to stop the timer without also risking a race with an hrtimer interrupt and having to explicitly check whether an interrupt should have occurred. When the timer is re-enabled it resumes without losing time, i.e. the CP0_Count value jumps to what it would have been had the timer not been disabled, which would also be impossible to do from userland with CP0_Cause.DC. The timer interrupt also cannot be lost, i.e. if a timer interrupt would have occurred had the timer not been disabled it is queued when the timer is re-enabled. This works by storing the nanosecond monotonic time when the master disable is set, and using it for various operations instead of the current monotonic time (e.g. when recalculating the bias when the CP0_Count is set), until the master disable is cleared again, i.e. the timer state is read/written as it would have been at that time. This state is exposed to userland via the read-only KVM_REG_MIPS_COUNT_RESUME virtual register so that userland can determine the exact time the master disable took effect. This should allow userland to atomically save the state of the timer, and later restore it. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: David Daney <david.daney@cavium.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:37 +00:00
/**
* kvm_mips_set_count_ctl() - Update the count control KVM register.
* @vcpu: Virtual CPU.
* @count_ctl: Count control register new value.
*
* Set the count control KVM register. The timer is updated accordingly.
*
* Returns: -EINVAL if reserved bits are set.
* 0 on success.
*/
int kvm_mips_set_count_ctl(struct kvm_vcpu *vcpu, s64 count_ctl)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
s64 changed = count_ctl ^ vcpu->arch.count_ctl;
s64 delta;
ktime_t expire, now;
uint32_t count, compare;
/* Only allow defined bits to be changed */
if (changed & ~(s64)(KVM_REG_MIPS_COUNT_CTL_DC))
return -EINVAL;
/* Apply new value */
vcpu->arch.count_ctl = count_ctl;
/* Master CP0_Count disable */
if (changed & KVM_REG_MIPS_COUNT_CTL_DC) {
/* Is CP0_Cause.DC already disabling CP0_Count? */
if (kvm_read_c0_guest_cause(cop0) & CAUSEF_DC) {
if (count_ctl & KVM_REG_MIPS_COUNT_CTL_DC)
/* Just record the current time */
vcpu->arch.count_resume = ktime_get();
} else if (count_ctl & KVM_REG_MIPS_COUNT_CTL_DC) {
/* disable timer and record current time */
vcpu->arch.count_resume = kvm_mips_count_disable(vcpu);
} else {
/*
* Calculate timeout relative to static count at resume
* time (wrap 0 to 2^32).
*/
count = kvm_read_c0_guest_count(cop0);
compare = kvm_read_c0_guest_compare(cop0);
delta = (u64)(uint32_t)(compare - count - 1) + 1;
delta = div_u64(delta * NSEC_PER_SEC,
vcpu->arch.count_hz);
expire = ktime_add_ns(vcpu->arch.count_resume, delta);
/* Handle pending interrupt */
now = ktime_get();
if (ktime_compare(now, expire) >= 0)
/* Nothing should be waiting on the timeout */
kvm_mips_callbacks->queue_timer_int(vcpu);
/* Resume hrtimer without changing bias */
count = kvm_mips_read_count_running(vcpu, now);
kvm_mips_resume_hrtimer(vcpu, now, count);
}
}
return 0;
}
/**
* kvm_mips_set_count_resume() - Update the count resume KVM register.
* @vcpu: Virtual CPU.
* @count_resume: Count resume register new value.
*
* Set the count resume KVM register.
*
* Returns: -EINVAL if out of valid range (0..now).
* 0 on success.
*/
int kvm_mips_set_count_resume(struct kvm_vcpu *vcpu, s64 count_resume)
{
/*
* It doesn't make sense for the resume time to be in the future, as it
* would be possible for the next interrupt to be more than a full
* period in the future.
*/
if (count_resume < 0 || count_resume > ktime_to_ns(ktime_get()))
return -EINVAL;
vcpu->arch.count_resume = ns_to_ktime(count_resume);
return 0;
}
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
/**
* kvm_mips_count_timeout() - Push timer forward on timeout.
* @vcpu: Virtual CPU.
*
* Handle an hrtimer event by push the hrtimer forward a period.
*
* Returns: The hrtimer_restart value to return to the hrtimer subsystem.
*/
enum hrtimer_restart kvm_mips_count_timeout(struct kvm_vcpu *vcpu)
{
/* Add the Count period to the current expiry time */
hrtimer_add_expires_ns(&vcpu->arch.comparecount_timer,
vcpu->arch.count_period);
return HRTIMER_RESTART;
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
}
enum emulation_result kvm_mips_emul_eret(struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
enum emulation_result er = EMULATE_DONE;
if (kvm_read_c0_guest_status(cop0) & ST0_EXL) {
kvm_debug("[%#lx] ERET to %#lx\n", vcpu->arch.pc,
kvm_read_c0_guest_epc(cop0));
kvm_clear_c0_guest_status(cop0, ST0_EXL);
vcpu->arch.pc = kvm_read_c0_guest_epc(cop0);
} else if (kvm_read_c0_guest_status(cop0) & ST0_ERL) {
kvm_clear_c0_guest_status(cop0, ST0_ERL);
vcpu->arch.pc = kvm_read_c0_guest_errorepc(cop0);
} else {
printk("[%#lx] ERET when MIPS_SR_EXL|MIPS_SR_ERL == 0\n",
vcpu->arch.pc);
er = EMULATE_FAIL;
}
return er;
}
enum emulation_result kvm_mips_emul_wait(struct kvm_vcpu *vcpu)
{
enum emulation_result er = EMULATE_DONE;
kvm_debug("[%#lx] !!!WAIT!!! (%#lx)\n", vcpu->arch.pc,
vcpu->arch.pending_exceptions);
++vcpu->stat.wait_exits;
trace_kvm_exit(vcpu, WAIT_EXITS);
if (!vcpu->arch.pending_exceptions) {
vcpu->arch.wait = 1;
kvm_vcpu_block(vcpu);
/* We we are runnable, then definitely go off to user space to check if any
* I/O interrupts are pending.
*/
if (kvm_check_request(KVM_REQ_UNHALT, vcpu)) {
clear_bit(KVM_REQ_UNHALT, &vcpu->requests);
vcpu->run->exit_reason = KVM_EXIT_IRQ_WINDOW_OPEN;
}
}
return er;
}
/* XXXKYMA: Linux doesn't seem to use TLBR, return EMULATE_FAIL for now so that we can catch
* this, if things ever change
*/
enum emulation_result kvm_mips_emul_tlbr(struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
enum emulation_result er = EMULATE_FAIL;
uint32_t pc = vcpu->arch.pc;
printk("[%#x] COP0_TLBR [%ld]\n", pc, kvm_read_c0_guest_index(cop0));
return er;
}
/* Write Guest TLB Entry @ Index */
enum emulation_result kvm_mips_emul_tlbwi(struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
int index = kvm_read_c0_guest_index(cop0);
enum emulation_result er = EMULATE_DONE;
struct kvm_mips_tlb *tlb = NULL;
uint32_t pc = vcpu->arch.pc;
if (index < 0 || index >= KVM_MIPS_GUEST_TLB_SIZE) {
printk("%s: illegal index: %d\n", __func__, index);
printk
("[%#x] COP0_TLBWI [%d] (entryhi: %#lx, entrylo0: %#lx entrylo1: %#lx, mask: %#lx)\n",
pc, index, kvm_read_c0_guest_entryhi(cop0),
kvm_read_c0_guest_entrylo0(cop0),
kvm_read_c0_guest_entrylo1(cop0),
kvm_read_c0_guest_pagemask(cop0));
index = (index & ~0x80000000) % KVM_MIPS_GUEST_TLB_SIZE;
}
tlb = &vcpu->arch.guest_tlb[index];
#if 1
/* Probe the shadow host TLB for the entry being overwritten, if one matches, invalidate it */
kvm_mips_host_tlb_inv(vcpu, tlb->tlb_hi);
#endif
tlb->tlb_mask = kvm_read_c0_guest_pagemask(cop0);
tlb->tlb_hi = kvm_read_c0_guest_entryhi(cop0);
tlb->tlb_lo0 = kvm_read_c0_guest_entrylo0(cop0);
tlb->tlb_lo1 = kvm_read_c0_guest_entrylo1(cop0);
kvm_debug
("[%#x] COP0_TLBWI [%d] (entryhi: %#lx, entrylo0: %#lx entrylo1: %#lx, mask: %#lx)\n",
pc, index, kvm_read_c0_guest_entryhi(cop0),
kvm_read_c0_guest_entrylo0(cop0), kvm_read_c0_guest_entrylo1(cop0),
kvm_read_c0_guest_pagemask(cop0));
return er;
}
/* Write Guest TLB Entry @ Random Index */
enum emulation_result kvm_mips_emul_tlbwr(struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
enum emulation_result er = EMULATE_DONE;
struct kvm_mips_tlb *tlb = NULL;
uint32_t pc = vcpu->arch.pc;
int index;
#if 1
get_random_bytes(&index, sizeof(index));
index &= (KVM_MIPS_GUEST_TLB_SIZE - 1);
#else
index = jiffies % KVM_MIPS_GUEST_TLB_SIZE;
#endif
if (index < 0 || index >= KVM_MIPS_GUEST_TLB_SIZE) {
printk("%s: illegal index: %d\n", __func__, index);
return EMULATE_FAIL;
}
tlb = &vcpu->arch.guest_tlb[index];
#if 1
/* Probe the shadow host TLB for the entry being overwritten, if one matches, invalidate it */
kvm_mips_host_tlb_inv(vcpu, tlb->tlb_hi);
#endif
tlb->tlb_mask = kvm_read_c0_guest_pagemask(cop0);
tlb->tlb_hi = kvm_read_c0_guest_entryhi(cop0);
tlb->tlb_lo0 = kvm_read_c0_guest_entrylo0(cop0);
tlb->tlb_lo1 = kvm_read_c0_guest_entrylo1(cop0);
kvm_debug
("[%#x] COP0_TLBWR[%d] (entryhi: %#lx, entrylo0: %#lx entrylo1: %#lx)\n",
pc, index, kvm_read_c0_guest_entryhi(cop0),
kvm_read_c0_guest_entrylo0(cop0),
kvm_read_c0_guest_entrylo1(cop0));
return er;
}
enum emulation_result kvm_mips_emul_tlbp(struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
long entryhi = kvm_read_c0_guest_entryhi(cop0);
enum emulation_result er = EMULATE_DONE;
uint32_t pc = vcpu->arch.pc;
int index = -1;
index = kvm_mips_guest_tlb_lookup(vcpu, entryhi);
kvm_write_c0_guest_index(cop0, index);
kvm_debug("[%#x] COP0_TLBP (entryhi: %#lx), index: %d\n", pc, entryhi,
index);
return er;
}
enum emulation_result
kvm_mips_emulate_CP0(uint32_t inst, uint32_t *opc, uint32_t cause,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
enum emulation_result er = EMULATE_DONE;
int32_t rt, rd, copz, sel, co_bit, op;
uint32_t pc = vcpu->arch.pc;
unsigned long curr_pc;
/*
* Update PC and hold onto current PC in case there is
* an error and we want to rollback the PC
*/
curr_pc = vcpu->arch.pc;
er = update_pc(vcpu, cause);
if (er == EMULATE_FAIL) {
return er;
}
copz = (inst >> 21) & 0x1f;
rt = (inst >> 16) & 0x1f;
rd = (inst >> 11) & 0x1f;
sel = inst & 0x7;
co_bit = (inst >> 25) & 1;
if (co_bit) {
op = (inst) & 0xff;
switch (op) {
case tlbr_op: /* Read indexed TLB entry */
er = kvm_mips_emul_tlbr(vcpu);
break;
case tlbwi_op: /* Write indexed */
er = kvm_mips_emul_tlbwi(vcpu);
break;
case tlbwr_op: /* Write random */
er = kvm_mips_emul_tlbwr(vcpu);
break;
case tlbp_op: /* TLB Probe */
er = kvm_mips_emul_tlbp(vcpu);
break;
case rfe_op:
printk("!!!COP0_RFE!!!\n");
break;
case eret_op:
er = kvm_mips_emul_eret(vcpu);
goto dont_update_pc;
break;
case wait_op:
er = kvm_mips_emul_wait(vcpu);
break;
}
} else {
switch (copz) {
case mfc_op:
#ifdef CONFIG_KVM_MIPS_DEBUG_COP0_COUNTERS
cop0->stat[rd][sel]++;
#endif
/* Get reg */
if ((rd == MIPS_CP0_COUNT) && (sel == 0)) {
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
vcpu->arch.gprs[rt] = kvm_mips_read_count(vcpu);
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
} else if ((rd == MIPS_CP0_ERRCTL) && (sel == 0)) {
vcpu->arch.gprs[rt] = 0x0;
#ifdef CONFIG_KVM_MIPS_DYN_TRANS
kvm_mips_trans_mfc0(inst, opc, vcpu);
#endif
}
else {
vcpu->arch.gprs[rt] = cop0->reg[rd][sel];
#ifdef CONFIG_KVM_MIPS_DYN_TRANS
kvm_mips_trans_mfc0(inst, opc, vcpu);
#endif
}
kvm_debug
("[%#x] MFCz[%d][%d], vcpu->arch.gprs[%d]: %#lx\n",
pc, rd, sel, rt, vcpu->arch.gprs[rt]);
break;
case dmfc_op:
vcpu->arch.gprs[rt] = cop0->reg[rd][sel];
break;
case mtc_op:
#ifdef CONFIG_KVM_MIPS_DEBUG_COP0_COUNTERS
cop0->stat[rd][sel]++;
#endif
if ((rd == MIPS_CP0_TLB_INDEX)
&& (vcpu->arch.gprs[rt] >=
KVM_MIPS_GUEST_TLB_SIZE)) {
printk("Invalid TLB Index: %ld",
vcpu->arch.gprs[rt]);
er = EMULATE_FAIL;
break;
}
#define C0_EBASE_CORE_MASK 0xff
if ((rd == MIPS_CP0_PRID) && (sel == 1)) {
/* Preserve CORE number */
kvm_change_c0_guest_ebase(cop0,
~(C0_EBASE_CORE_MASK),
vcpu->arch.gprs[rt]);
printk("MTCz, cop0->reg[EBASE]: %#lx\n",
kvm_read_c0_guest_ebase(cop0));
} else if (rd == MIPS_CP0_TLB_HI && sel == 0) {
Revert "MIPS: Allow ASID size to be determined at boot time." This reverts commit d532f3d26716a39dfd4b88d687bd344fbe77e390. The original commit has several problems: 1) Doesn't work with 64-bit kernels. 2) Calls TLBMISS_HANDLER_SETUP() before the code is generated. 3) Calls TLBMISS_HANDLER_SETUP() twice in per_cpu_trap_init() when only one call is needed. [ralf@linux-mips.org: Also revert the bits of the ASID patch which were hidden in the KVM merge.] Signed-off-by: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: "Steven J. Hill" <Steven.Hill@imgtec.com> Cc: David Daney <david.daney@cavium.com> Patchwork: https://patchwork.linux-mips.org/patch/5242/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-05-13 20:56:44 +00:00
uint32_t nasid =
vcpu->arch.gprs[rt] & ASID_MASK;
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
if ((KSEGX(vcpu->arch.gprs[rt]) != CKSEG0)
&&
Revert "MIPS: Allow ASID size to be determined at boot time." This reverts commit d532f3d26716a39dfd4b88d687bd344fbe77e390. The original commit has several problems: 1) Doesn't work with 64-bit kernels. 2) Calls TLBMISS_HANDLER_SETUP() before the code is generated. 3) Calls TLBMISS_HANDLER_SETUP() twice in per_cpu_trap_init() when only one call is needed. [ralf@linux-mips.org: Also revert the bits of the ASID patch which were hidden in the KVM merge.] Signed-off-by: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: "Steven J. Hill" <Steven.Hill@imgtec.com> Cc: David Daney <david.daney@cavium.com> Patchwork: https://patchwork.linux-mips.org/patch/5242/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-05-13 20:56:44 +00:00
((kvm_read_c0_guest_entryhi(cop0) &
ASID_MASK) != nasid)) {
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
kvm_debug
("MTCz, change ASID from %#lx to %#lx\n",
Revert "MIPS: Allow ASID size to be determined at boot time." This reverts commit d532f3d26716a39dfd4b88d687bd344fbe77e390. The original commit has several problems: 1) Doesn't work with 64-bit kernels. 2) Calls TLBMISS_HANDLER_SETUP() before the code is generated. 3) Calls TLBMISS_HANDLER_SETUP() twice in per_cpu_trap_init() when only one call is needed. [ralf@linux-mips.org: Also revert the bits of the ASID patch which were hidden in the KVM merge.] Signed-off-by: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: "Steven J. Hill" <Steven.Hill@imgtec.com> Cc: David Daney <david.daney@cavium.com> Patchwork: https://patchwork.linux-mips.org/patch/5242/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-05-13 20:56:44 +00:00
kvm_read_c0_guest_entryhi(cop0) &
ASID_MASK,
vcpu->arch.gprs[rt] & ASID_MASK);
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
/* Blow away the shadow host TLBs */
kvm_mips_flush_host_tlb(1);
}
kvm_write_c0_guest_entryhi(cop0,
vcpu->arch.gprs[rt]);
}
/* Are we writing to COUNT */
else if ((rd == MIPS_CP0_COUNT) && (sel == 0)) {
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
kvm_mips_write_count(vcpu, vcpu->arch.gprs[rt]);
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
goto done;
} else if ((rd == MIPS_CP0_COMPARE) && (sel == 0)) {
kvm_debug("[%#x] MTCz, COMPARE %#lx <- %#lx\n",
pc, kvm_read_c0_guest_compare(cop0),
vcpu->arch.gprs[rt]);
/* If we are writing to COMPARE */
/* Clear pending timer interrupt, if any */
kvm_mips_callbacks->dequeue_timer_int(vcpu);
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
kvm_mips_write_compare(vcpu,
vcpu->arch.gprs[rt]);
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
} else if ((rd == MIPS_CP0_STATUS) && (sel == 0)) {
kvm_write_c0_guest_status(cop0,
vcpu->arch.gprs[rt]);
/* Make sure that CU1 and NMI bits are never set */
kvm_clear_c0_guest_status(cop0,
(ST0_CU1 | ST0_NMI));
#ifdef CONFIG_KVM_MIPS_DYN_TRANS
kvm_mips_trans_mtc0(inst, opc, vcpu);
#endif
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
} else if ((rd == MIPS_CP0_CAUSE) && (sel == 0)) {
uint32_t old_cause, new_cause;
old_cause = kvm_read_c0_guest_cause(cop0);
new_cause = vcpu->arch.gprs[rt];
/* Update R/W bits */
kvm_change_c0_guest_cause(cop0, 0x08800300,
new_cause);
/* DC bit enabling/disabling timer? */
if ((old_cause ^ new_cause) & CAUSEF_DC) {
if (new_cause & CAUSEF_DC)
kvm_mips_count_disable_cause(vcpu);
else
kvm_mips_count_enable_cause(vcpu);
}
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
} else {
cop0->reg[rd][sel] = vcpu->arch.gprs[rt];
#ifdef CONFIG_KVM_MIPS_DYN_TRANS
kvm_mips_trans_mtc0(inst, opc, vcpu);
#endif
}
kvm_debug("[%#x] MTCz, cop0->reg[%d][%d]: %#lx\n", pc,
rd, sel, cop0->reg[rd][sel]);
break;
case dmtc_op:
printk
("!!!!!!![%#lx]dmtc_op: rt: %d, rd: %d, sel: %d!!!!!!\n",
vcpu->arch.pc, rt, rd, sel);
er = EMULATE_FAIL;
break;
case mfmcz_op:
#ifdef KVM_MIPS_DEBUG_COP0_COUNTERS
cop0->stat[MIPS_CP0_STATUS][0]++;
#endif
if (rt != 0) {
vcpu->arch.gprs[rt] =
kvm_read_c0_guest_status(cop0);
}
/* EI */
if (inst & 0x20) {
kvm_debug("[%#lx] mfmcz_op: EI\n",
vcpu->arch.pc);
kvm_set_c0_guest_status(cop0, ST0_IE);
} else {
kvm_debug("[%#lx] mfmcz_op: DI\n",
vcpu->arch.pc);
kvm_clear_c0_guest_status(cop0, ST0_IE);
}
break;
case wrpgpr_op:
{
uint32_t css =
cop0->reg[MIPS_CP0_STATUS][2] & 0xf;
uint32_t pss =
(cop0->reg[MIPS_CP0_STATUS][2] >> 6) & 0xf;
/* We don't support any shadow register sets, so SRSCtl[PSS] == SRSCtl[CSS] = 0 */
if (css || pss) {
er = EMULATE_FAIL;
break;
}
kvm_debug("WRPGPR[%d][%d] = %#lx\n", pss, rd,
vcpu->arch.gprs[rt]);
vcpu->arch.gprs[rd] = vcpu->arch.gprs[rt];
}
break;
default:
printk
("[%#lx]MachEmulateCP0: unsupported COP0, copz: 0x%x\n",
vcpu->arch.pc, copz);
er = EMULATE_FAIL;
break;
}
}
done:
/*
* Rollback PC only if emulation was unsuccessful
*/
if (er == EMULATE_FAIL) {
vcpu->arch.pc = curr_pc;
}
dont_update_pc:
/*
* This is for special instructions whose emulation
* updates the PC, so do not overwrite the PC under
* any circumstances
*/
return er;
}
enum emulation_result
kvm_mips_emulate_store(uint32_t inst, uint32_t cause,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
enum emulation_result er = EMULATE_DO_MMIO;
int32_t op, base, rt, offset;
uint32_t bytes;
void *data = run->mmio.data;
unsigned long curr_pc;
/*
* Update PC and hold onto current PC in case there is
* an error and we want to rollback the PC
*/
curr_pc = vcpu->arch.pc;
er = update_pc(vcpu, cause);
if (er == EMULATE_FAIL)
return er;
rt = (inst >> 16) & 0x1f;
base = (inst >> 21) & 0x1f;
offset = inst & 0xffff;
op = (inst >> 26) & 0x3f;
switch (op) {
case sb_op:
bytes = 1;
if (bytes > sizeof(run->mmio.data)) {
kvm_err("%s: bad MMIO length: %d\n", __func__,
run->mmio.len);
}
run->mmio.phys_addr =
kvm_mips_callbacks->gva_to_gpa(vcpu->arch.
host_cp0_badvaddr);
if (run->mmio.phys_addr == KVM_INVALID_ADDR) {
er = EMULATE_FAIL;
break;
}
run->mmio.len = bytes;
run->mmio.is_write = 1;
vcpu->mmio_needed = 1;
vcpu->mmio_is_write = 1;
*(u8 *) data = vcpu->arch.gprs[rt];
kvm_debug("OP_SB: eaddr: %#lx, gpr: %#lx, data: %#x\n",
vcpu->arch.host_cp0_badvaddr, vcpu->arch.gprs[rt],
*(uint8_t *) data);
break;
case sw_op:
bytes = 4;
if (bytes > sizeof(run->mmio.data)) {
kvm_err("%s: bad MMIO length: %d\n", __func__,
run->mmio.len);
}
run->mmio.phys_addr =
kvm_mips_callbacks->gva_to_gpa(vcpu->arch.
host_cp0_badvaddr);
if (run->mmio.phys_addr == KVM_INVALID_ADDR) {
er = EMULATE_FAIL;
break;
}
run->mmio.len = bytes;
run->mmio.is_write = 1;
vcpu->mmio_needed = 1;
vcpu->mmio_is_write = 1;
*(uint32_t *) data = vcpu->arch.gprs[rt];
kvm_debug("[%#lx] OP_SW: eaddr: %#lx, gpr: %#lx, data: %#x\n",
vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
vcpu->arch.gprs[rt], *(uint32_t *) data);
break;
case sh_op:
bytes = 2;
if (bytes > sizeof(run->mmio.data)) {
kvm_err("%s: bad MMIO length: %d\n", __func__,
run->mmio.len);
}
run->mmio.phys_addr =
kvm_mips_callbacks->gva_to_gpa(vcpu->arch.
host_cp0_badvaddr);
if (run->mmio.phys_addr == KVM_INVALID_ADDR) {
er = EMULATE_FAIL;
break;
}
run->mmio.len = bytes;
run->mmio.is_write = 1;
vcpu->mmio_needed = 1;
vcpu->mmio_is_write = 1;
*(uint16_t *) data = vcpu->arch.gprs[rt];
kvm_debug("[%#lx] OP_SH: eaddr: %#lx, gpr: %#lx, data: %#x\n",
vcpu->arch.pc, vcpu->arch.host_cp0_badvaddr,
vcpu->arch.gprs[rt], *(uint32_t *) data);
break;
default:
printk("Store not yet supported");
er = EMULATE_FAIL;
break;
}
/*
* Rollback PC if emulation was unsuccessful
*/
if (er == EMULATE_FAIL) {
vcpu->arch.pc = curr_pc;
}
return er;
}
enum emulation_result
kvm_mips_emulate_load(uint32_t inst, uint32_t cause,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
enum emulation_result er = EMULATE_DO_MMIO;
int32_t op, base, rt, offset;
uint32_t bytes;
rt = (inst >> 16) & 0x1f;
base = (inst >> 21) & 0x1f;
offset = inst & 0xffff;
op = (inst >> 26) & 0x3f;
vcpu->arch.pending_load_cause = cause;
vcpu->arch.io_gpr = rt;
switch (op) {
case lw_op:
bytes = 4;
if (bytes > sizeof(run->mmio.data)) {
kvm_err("%s: bad MMIO length: %d\n", __func__,
run->mmio.len);
er = EMULATE_FAIL;
break;
}
run->mmio.phys_addr =
kvm_mips_callbacks->gva_to_gpa(vcpu->arch.
host_cp0_badvaddr);
if (run->mmio.phys_addr == KVM_INVALID_ADDR) {
er = EMULATE_FAIL;
break;
}
run->mmio.len = bytes;
run->mmio.is_write = 0;
vcpu->mmio_needed = 1;
vcpu->mmio_is_write = 0;
break;
case lh_op:
case lhu_op:
bytes = 2;
if (bytes > sizeof(run->mmio.data)) {
kvm_err("%s: bad MMIO length: %d\n", __func__,
run->mmio.len);
er = EMULATE_FAIL;
break;
}
run->mmio.phys_addr =
kvm_mips_callbacks->gva_to_gpa(vcpu->arch.
host_cp0_badvaddr);
if (run->mmio.phys_addr == KVM_INVALID_ADDR) {
er = EMULATE_FAIL;
break;
}
run->mmio.len = bytes;
run->mmio.is_write = 0;
vcpu->mmio_needed = 1;
vcpu->mmio_is_write = 0;
if (op == lh_op)
vcpu->mmio_needed = 2;
else
vcpu->mmio_needed = 1;
break;
case lbu_op:
case lb_op:
bytes = 1;
if (bytes > sizeof(run->mmio.data)) {
kvm_err("%s: bad MMIO length: %d\n", __func__,
run->mmio.len);
er = EMULATE_FAIL;
break;
}
run->mmio.phys_addr =
kvm_mips_callbacks->gva_to_gpa(vcpu->arch.
host_cp0_badvaddr);
if (run->mmio.phys_addr == KVM_INVALID_ADDR) {
er = EMULATE_FAIL;
break;
}
run->mmio.len = bytes;
run->mmio.is_write = 0;
vcpu->mmio_is_write = 0;
if (op == lb_op)
vcpu->mmio_needed = 2;
else
vcpu->mmio_needed = 1;
break;
default:
printk("Load not yet supported");
er = EMULATE_FAIL;
break;
}
return er;
}
int kvm_mips_sync_icache(unsigned long va, struct kvm_vcpu *vcpu)
{
unsigned long offset = (va & ~PAGE_MASK);
struct kvm *kvm = vcpu->kvm;
unsigned long pa;
gfn_t gfn;
pfn_t pfn;
gfn = va >> PAGE_SHIFT;
if (gfn >= kvm->arch.guest_pmap_npages) {
printk("%s: Invalid gfn: %#llx\n", __func__, gfn);
kvm_mips_dump_host_tlbs();
kvm_arch_vcpu_dump_regs(vcpu);
return -1;
}
pfn = kvm->arch.guest_pmap[gfn];
pa = (pfn << PAGE_SHIFT) | offset;
printk("%s: va: %#lx, unmapped: %#x\n", __func__, va, CKSEG0ADDR(pa));
MIPS: KVM: Use local_flush_icache_range to fix RI on XBurst MIPS KVM uses mips32_SyncICache to synchronise the icache with the dcache after dynamically modifying guest instructions or writing guest exception vector. However this uses rdhwr to get the SYNCI step, which causes a reserved instruction exception on Ingenic XBurst cores. It would seem to make more sense to use local_flush_icache_range() instead which does the same thing but is more portable. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:25 +00:00
local_flush_icache_range(CKSEG0ADDR(pa), 32);
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
return 0;
}
#define MIPS_CACHE_OP_INDEX_INV 0x0
#define MIPS_CACHE_OP_INDEX_LD_TAG 0x1
#define MIPS_CACHE_OP_INDEX_ST_TAG 0x2
#define MIPS_CACHE_OP_IMP 0x3
#define MIPS_CACHE_OP_HIT_INV 0x4
#define MIPS_CACHE_OP_FILL_WB_INV 0x5
#define MIPS_CACHE_OP_HIT_HB 0x6
#define MIPS_CACHE_OP_FETCH_LOCK 0x7
#define MIPS_CACHE_ICACHE 0x0
#define MIPS_CACHE_DCACHE 0x1
#define MIPS_CACHE_SEC 0x3
enum emulation_result
kvm_mips_emulate_cache(uint32_t inst, uint32_t *opc, uint32_t cause,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
extern void (*r4k_blast_dcache) (void);
extern void (*r4k_blast_icache) (void);
enum emulation_result er = EMULATE_DONE;
int32_t offset, cache, op_inst, op, base;
struct kvm_vcpu_arch *arch = &vcpu->arch;
unsigned long va;
unsigned long curr_pc;
/*
* Update PC and hold onto current PC in case there is
* an error and we want to rollback the PC
*/
curr_pc = vcpu->arch.pc;
er = update_pc(vcpu, cause);
if (er == EMULATE_FAIL)
return er;
base = (inst >> 21) & 0x1f;
op_inst = (inst >> 16) & 0x1f;
offset = inst & 0xffff;
cache = (inst >> 16) & 0x3;
op = (inst >> 18) & 0x7;
va = arch->gprs[base] + offset;
kvm_debug("CACHE (cache: %#x, op: %#x, base[%d]: %#lx, offset: %#x\n",
cache, op, base, arch->gprs[base], offset);
/* Treat INDEX_INV as a nop, basically issued by Linux on startup to invalidate
* the caches entirely by stepping through all the ways/indexes
*/
if (op == MIPS_CACHE_OP_INDEX_INV) {
kvm_debug
("@ %#lx/%#lx CACHE (cache: %#x, op: %#x, base[%d]: %#lx, offset: %#x\n",
vcpu->arch.pc, vcpu->arch.gprs[31], cache, op, base,
arch->gprs[base], offset);
if (cache == MIPS_CACHE_DCACHE)
r4k_blast_dcache();
else if (cache == MIPS_CACHE_ICACHE)
r4k_blast_icache();
else {
printk("%s: unsupported CACHE INDEX operation\n",
__func__);
return EMULATE_FAIL;
}
#ifdef CONFIG_KVM_MIPS_DYN_TRANS
kvm_mips_trans_cache_index(inst, opc, vcpu);
#endif
goto done;
}
preempt_disable();
if (KVM_GUEST_KSEGX(va) == KVM_GUEST_KSEG0) {
if (kvm_mips_host_tlb_lookup(vcpu, va) < 0) {
kvm_mips_handle_kseg0_tlb_fault(va, vcpu);
}
} else if ((KVM_GUEST_KSEGX(va) < KVM_GUEST_KSEG0) ||
KVM_GUEST_KSEGX(va) == KVM_GUEST_KSEG23) {
int index;
/* If an entry already exists then skip */
if (kvm_mips_host_tlb_lookup(vcpu, va) >= 0) {
goto skip_fault;
}
/* If address not in the guest TLB, then give the guest a fault, the
* resulting handler will do the right thing
*/
index = kvm_mips_guest_tlb_lookup(vcpu, (va & VPN2_MASK) |
Revert "MIPS: Allow ASID size to be determined at boot time." This reverts commit d532f3d26716a39dfd4b88d687bd344fbe77e390. The original commit has several problems: 1) Doesn't work with 64-bit kernels. 2) Calls TLBMISS_HANDLER_SETUP() before the code is generated. 3) Calls TLBMISS_HANDLER_SETUP() twice in per_cpu_trap_init() when only one call is needed. [ralf@linux-mips.org: Also revert the bits of the ASID patch which were hidden in the KVM merge.] Signed-off-by: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: "Steven J. Hill" <Steven.Hill@imgtec.com> Cc: David Daney <david.daney@cavium.com> Patchwork: https://patchwork.linux-mips.org/patch/5242/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-05-13 20:56:44 +00:00
(kvm_read_c0_guest_entryhi
(cop0) & ASID_MASK));
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
if (index < 0) {
vcpu->arch.host_cp0_entryhi = (va & VPN2_MASK);
vcpu->arch.host_cp0_badvaddr = va;
er = kvm_mips_emulate_tlbmiss_ld(cause, NULL, run,
vcpu);
preempt_enable();
goto dont_update_pc;
} else {
struct kvm_mips_tlb *tlb = &vcpu->arch.guest_tlb[index];
/* Check if the entry is valid, if not then setup a TLB invalid exception to the guest */
if (!TLB_IS_VALID(*tlb, va)) {
er = kvm_mips_emulate_tlbinv_ld(cause, NULL,
run, vcpu);
preempt_enable();
goto dont_update_pc;
} else {
/* We fault an entry from the guest tlb to the shadow host TLB */
kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb,
NULL,
NULL);
}
}
} else {
printk
("INVALID CACHE INDEX/ADDRESS (cache: %#x, op: %#x, base[%d]: %#lx, offset: %#x\n",
cache, op, base, arch->gprs[base], offset);
er = EMULATE_FAIL;
preempt_enable();
goto dont_update_pc;
}
skip_fault:
/* XXXKYMA: Only a subset of cache ops are supported, used by Linux */
if (cache == MIPS_CACHE_DCACHE
&& (op == MIPS_CACHE_OP_FILL_WB_INV
|| op == MIPS_CACHE_OP_HIT_INV)) {
flush_dcache_line(va);
#ifdef CONFIG_KVM_MIPS_DYN_TRANS
/* Replace the CACHE instruction, with a SYNCI, not the same, but avoids a trap */
kvm_mips_trans_cache_va(inst, opc, vcpu);
#endif
} else if (op == MIPS_CACHE_OP_HIT_INV && cache == MIPS_CACHE_ICACHE) {
flush_dcache_line(va);
flush_icache_line(va);
#ifdef CONFIG_KVM_MIPS_DYN_TRANS
/* Replace the CACHE instruction, with a SYNCI */
kvm_mips_trans_cache_va(inst, opc, vcpu);
#endif
} else {
printk
("NO-OP CACHE (cache: %#x, op: %#x, base[%d]: %#lx, offset: %#x\n",
cache, op, base, arch->gprs[base], offset);
er = EMULATE_FAIL;
preempt_enable();
goto dont_update_pc;
}
preempt_enable();
dont_update_pc:
/*
* Rollback PC
*/
vcpu->arch.pc = curr_pc;
done:
return er;
}
enum emulation_result
kvm_mips_emulate_inst(unsigned long cause, uint32_t *opc,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
enum emulation_result er = EMULATE_DONE;
uint32_t inst;
/*
* Fetch the instruction.
*/
if (cause & CAUSEF_BD) {
opc += 1;
}
inst = kvm_get_inst(opc, vcpu);
switch (((union mips_instruction)inst).r_format.opcode) {
case cop0_op:
er = kvm_mips_emulate_CP0(inst, opc, cause, run, vcpu);
break;
case sb_op:
case sh_op:
case sw_op:
er = kvm_mips_emulate_store(inst, cause, run, vcpu);
break;
case lb_op:
case lbu_op:
case lhu_op:
case lh_op:
case lw_op:
er = kvm_mips_emulate_load(inst, cause, run, vcpu);
break;
case cache_op:
++vcpu->stat.cache_exits;
trace_kvm_exit(vcpu, CACHE_EXITS);
er = kvm_mips_emulate_cache(inst, opc, cause, run, vcpu);
break;
default:
printk("Instruction emulation not supported (%p/%#x)\n", opc,
inst);
kvm_arch_vcpu_dump_regs(vcpu);
er = EMULATE_FAIL;
break;
}
return er;
}
enum emulation_result
kvm_mips_emulate_syscall(unsigned long cause, uint32_t *opc,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
struct kvm_vcpu_arch *arch = &vcpu->arch;
enum emulation_result er = EMULATE_DONE;
if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
/* save old pc */
kvm_write_c0_guest_epc(cop0, arch->pc);
kvm_set_c0_guest_status(cop0, ST0_EXL);
if (cause & CAUSEF_BD)
kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
else
kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
kvm_debug("Delivering SYSCALL @ pc %#lx\n", arch->pc);
kvm_change_c0_guest_cause(cop0, (0xff),
(T_SYSCALL << CAUSEB_EXCCODE));
/* Set PC to the exception entry point */
arch->pc = KVM_GUEST_KSEG0 + 0x180;
} else {
printk("Trying to deliver SYSCALL when EXL is already set\n");
er = EMULATE_FAIL;
}
return er;
}
enum emulation_result
kvm_mips_emulate_tlbmiss_ld(unsigned long cause, uint32_t *opc,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
struct kvm_vcpu_arch *arch = &vcpu->arch;
enum emulation_result er = EMULATE_DONE;
unsigned long entryhi = (vcpu->arch. host_cp0_badvaddr & VPN2_MASK) |
Revert "MIPS: Allow ASID size to be determined at boot time." This reverts commit d532f3d26716a39dfd4b88d687bd344fbe77e390. The original commit has several problems: 1) Doesn't work with 64-bit kernels. 2) Calls TLBMISS_HANDLER_SETUP() before the code is generated. 3) Calls TLBMISS_HANDLER_SETUP() twice in per_cpu_trap_init() when only one call is needed. [ralf@linux-mips.org: Also revert the bits of the ASID patch which were hidden in the KVM merge.] Signed-off-by: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: "Steven J. Hill" <Steven.Hill@imgtec.com> Cc: David Daney <david.daney@cavium.com> Patchwork: https://patchwork.linux-mips.org/patch/5242/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-05-13 20:56:44 +00:00
(kvm_read_c0_guest_entryhi(cop0) & ASID_MASK);
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
/* save old pc */
kvm_write_c0_guest_epc(cop0, arch->pc);
kvm_set_c0_guest_status(cop0, ST0_EXL);
if (cause & CAUSEF_BD)
kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
else
kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
kvm_debug("[EXL == 0] delivering TLB MISS @ pc %#lx\n",
arch->pc);
/* set pc to the exception entry point */
arch->pc = KVM_GUEST_KSEG0 + 0x0;
} else {
kvm_debug("[EXL == 1] delivering TLB MISS @ pc %#lx\n",
arch->pc);
arch->pc = KVM_GUEST_KSEG0 + 0x180;
}
kvm_change_c0_guest_cause(cop0, (0xff),
(T_TLB_LD_MISS << CAUSEB_EXCCODE));
/* setup badvaddr, context and entryhi registers for the guest */
kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
/* XXXKYMA: is the context register used by linux??? */
kvm_write_c0_guest_entryhi(cop0, entryhi);
/* Blow away the shadow host TLBs */
kvm_mips_flush_host_tlb(1);
return er;
}
enum emulation_result
kvm_mips_emulate_tlbinv_ld(unsigned long cause, uint32_t *opc,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
struct kvm_vcpu_arch *arch = &vcpu->arch;
enum emulation_result er = EMULATE_DONE;
unsigned long entryhi =
(vcpu->arch.host_cp0_badvaddr & VPN2_MASK) |
Revert "MIPS: Allow ASID size to be determined at boot time." This reverts commit d532f3d26716a39dfd4b88d687bd344fbe77e390. The original commit has several problems: 1) Doesn't work with 64-bit kernels. 2) Calls TLBMISS_HANDLER_SETUP() before the code is generated. 3) Calls TLBMISS_HANDLER_SETUP() twice in per_cpu_trap_init() when only one call is needed. [ralf@linux-mips.org: Also revert the bits of the ASID patch which were hidden in the KVM merge.] Signed-off-by: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: "Steven J. Hill" <Steven.Hill@imgtec.com> Cc: David Daney <david.daney@cavium.com> Patchwork: https://patchwork.linux-mips.org/patch/5242/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-05-13 20:56:44 +00:00
(kvm_read_c0_guest_entryhi(cop0) & ASID_MASK);
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
/* save old pc */
kvm_write_c0_guest_epc(cop0, arch->pc);
kvm_set_c0_guest_status(cop0, ST0_EXL);
if (cause & CAUSEF_BD)
kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
else
kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
kvm_debug("[EXL == 0] delivering TLB INV @ pc %#lx\n",
arch->pc);
/* set pc to the exception entry point */
arch->pc = KVM_GUEST_KSEG0 + 0x180;
} else {
kvm_debug("[EXL == 1] delivering TLB MISS @ pc %#lx\n",
arch->pc);
arch->pc = KVM_GUEST_KSEG0 + 0x180;
}
kvm_change_c0_guest_cause(cop0, (0xff),
(T_TLB_LD_MISS << CAUSEB_EXCCODE));
/* setup badvaddr, context and entryhi registers for the guest */
kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
/* XXXKYMA: is the context register used by linux??? */
kvm_write_c0_guest_entryhi(cop0, entryhi);
/* Blow away the shadow host TLBs */
kvm_mips_flush_host_tlb(1);
return er;
}
enum emulation_result
kvm_mips_emulate_tlbmiss_st(unsigned long cause, uint32_t *opc,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
struct kvm_vcpu_arch *arch = &vcpu->arch;
enum emulation_result er = EMULATE_DONE;
unsigned long entryhi = (vcpu->arch.host_cp0_badvaddr & VPN2_MASK) |
Revert "MIPS: Allow ASID size to be determined at boot time." This reverts commit d532f3d26716a39dfd4b88d687bd344fbe77e390. The original commit has several problems: 1) Doesn't work with 64-bit kernels. 2) Calls TLBMISS_HANDLER_SETUP() before the code is generated. 3) Calls TLBMISS_HANDLER_SETUP() twice in per_cpu_trap_init() when only one call is needed. [ralf@linux-mips.org: Also revert the bits of the ASID patch which were hidden in the KVM merge.] Signed-off-by: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: "Steven J. Hill" <Steven.Hill@imgtec.com> Cc: David Daney <david.daney@cavium.com> Patchwork: https://patchwork.linux-mips.org/patch/5242/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-05-13 20:56:44 +00:00
(kvm_read_c0_guest_entryhi(cop0) & ASID_MASK);
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
/* save old pc */
kvm_write_c0_guest_epc(cop0, arch->pc);
kvm_set_c0_guest_status(cop0, ST0_EXL);
if (cause & CAUSEF_BD)
kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
else
kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
kvm_debug("[EXL == 0] Delivering TLB MISS @ pc %#lx\n",
arch->pc);
/* Set PC to the exception entry point */
arch->pc = KVM_GUEST_KSEG0 + 0x0;
} else {
kvm_debug("[EXL == 1] Delivering TLB MISS @ pc %#lx\n",
arch->pc);
arch->pc = KVM_GUEST_KSEG0 + 0x180;
}
kvm_change_c0_guest_cause(cop0, (0xff),
(T_TLB_ST_MISS << CAUSEB_EXCCODE));
/* setup badvaddr, context and entryhi registers for the guest */
kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
/* XXXKYMA: is the context register used by linux??? */
kvm_write_c0_guest_entryhi(cop0, entryhi);
/* Blow away the shadow host TLBs */
kvm_mips_flush_host_tlb(1);
return er;
}
enum emulation_result
kvm_mips_emulate_tlbinv_st(unsigned long cause, uint32_t *opc,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
struct kvm_vcpu_arch *arch = &vcpu->arch;
enum emulation_result er = EMULATE_DONE;
unsigned long entryhi = (vcpu->arch.host_cp0_badvaddr & VPN2_MASK) |
Revert "MIPS: Allow ASID size to be determined at boot time." This reverts commit d532f3d26716a39dfd4b88d687bd344fbe77e390. The original commit has several problems: 1) Doesn't work with 64-bit kernels. 2) Calls TLBMISS_HANDLER_SETUP() before the code is generated. 3) Calls TLBMISS_HANDLER_SETUP() twice in per_cpu_trap_init() when only one call is needed. [ralf@linux-mips.org: Also revert the bits of the ASID patch which were hidden in the KVM merge.] Signed-off-by: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: "Steven J. Hill" <Steven.Hill@imgtec.com> Cc: David Daney <david.daney@cavium.com> Patchwork: https://patchwork.linux-mips.org/patch/5242/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-05-13 20:56:44 +00:00
(kvm_read_c0_guest_entryhi(cop0) & ASID_MASK);
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
/* save old pc */
kvm_write_c0_guest_epc(cop0, arch->pc);
kvm_set_c0_guest_status(cop0, ST0_EXL);
if (cause & CAUSEF_BD)
kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
else
kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
kvm_debug("[EXL == 0] Delivering TLB MISS @ pc %#lx\n",
arch->pc);
/* Set PC to the exception entry point */
arch->pc = KVM_GUEST_KSEG0 + 0x180;
} else {
kvm_debug("[EXL == 1] Delivering TLB MISS @ pc %#lx\n",
arch->pc);
arch->pc = KVM_GUEST_KSEG0 + 0x180;
}
kvm_change_c0_guest_cause(cop0, (0xff),
(T_TLB_ST_MISS << CAUSEB_EXCCODE));
/* setup badvaddr, context and entryhi registers for the guest */
kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
/* XXXKYMA: is the context register used by linux??? */
kvm_write_c0_guest_entryhi(cop0, entryhi);
/* Blow away the shadow host TLBs */
kvm_mips_flush_host_tlb(1);
return er;
}
/* TLBMOD: store into address matching TLB with Dirty bit off */
enum emulation_result
kvm_mips_handle_tlbmod(unsigned long cause, uint32_t *opc,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
enum emulation_result er = EMULATE_DONE;
#ifdef DEBUG
/*
* If address not in the guest TLB, then we are in trouble
*/
index = kvm_mips_guest_tlb_lookup(vcpu, entryhi);
if (index < 0) {
/* XXXKYMA Invalidate and retry */
kvm_mips_host_tlb_inv(vcpu, vcpu->arch.host_cp0_badvaddr);
kvm_err("%s: host got TLBMOD for %#lx but entry not present in Guest TLB\n",
__func__, entryhi);
kvm_mips_dump_guest_tlbs(vcpu);
kvm_mips_dump_host_tlbs();
return EMULATE_FAIL;
}
#endif
er = kvm_mips_emulate_tlbmod(cause, opc, run, vcpu);
return er;
}
enum emulation_result
kvm_mips_emulate_tlbmod(unsigned long cause, uint32_t *opc,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
unsigned long entryhi = (vcpu->arch.host_cp0_badvaddr & VPN2_MASK) |
Revert "MIPS: Allow ASID size to be determined at boot time." This reverts commit d532f3d26716a39dfd4b88d687bd344fbe77e390. The original commit has several problems: 1) Doesn't work with 64-bit kernels. 2) Calls TLBMISS_HANDLER_SETUP() before the code is generated. 3) Calls TLBMISS_HANDLER_SETUP() twice in per_cpu_trap_init() when only one call is needed. [ralf@linux-mips.org: Also revert the bits of the ASID patch which were hidden in the KVM merge.] Signed-off-by: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: "Steven J. Hill" <Steven.Hill@imgtec.com> Cc: David Daney <david.daney@cavium.com> Patchwork: https://patchwork.linux-mips.org/patch/5242/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-05-13 20:56:44 +00:00
(kvm_read_c0_guest_entryhi(cop0) & ASID_MASK);
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
struct kvm_vcpu_arch *arch = &vcpu->arch;
enum emulation_result er = EMULATE_DONE;
if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
/* save old pc */
kvm_write_c0_guest_epc(cop0, arch->pc);
kvm_set_c0_guest_status(cop0, ST0_EXL);
if (cause & CAUSEF_BD)
kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
else
kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
kvm_debug("[EXL == 0] Delivering TLB MOD @ pc %#lx\n",
arch->pc);
arch->pc = KVM_GUEST_KSEG0 + 0x180;
} else {
kvm_debug("[EXL == 1] Delivering TLB MOD @ pc %#lx\n",
arch->pc);
arch->pc = KVM_GUEST_KSEG0 + 0x180;
}
kvm_change_c0_guest_cause(cop0, (0xff), (T_TLB_MOD << CAUSEB_EXCCODE));
/* setup badvaddr, context and entryhi registers for the guest */
kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
/* XXXKYMA: is the context register used by linux??? */
kvm_write_c0_guest_entryhi(cop0, entryhi);
/* Blow away the shadow host TLBs */
kvm_mips_flush_host_tlb(1);
return er;
}
enum emulation_result
kvm_mips_emulate_fpu_exc(unsigned long cause, uint32_t *opc,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
struct kvm_vcpu_arch *arch = &vcpu->arch;
enum emulation_result er = EMULATE_DONE;
if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
/* save old pc */
kvm_write_c0_guest_epc(cop0, arch->pc);
kvm_set_c0_guest_status(cop0, ST0_EXL);
if (cause & CAUSEF_BD)
kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
else
kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
}
arch->pc = KVM_GUEST_KSEG0 + 0x180;
kvm_change_c0_guest_cause(cop0, (0xff),
(T_COP_UNUSABLE << CAUSEB_EXCCODE));
kvm_change_c0_guest_cause(cop0, (CAUSEF_CE), (0x1 << CAUSEB_CE));
return er;
}
enum emulation_result
kvm_mips_emulate_ri_exc(unsigned long cause, uint32_t *opc,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
struct kvm_vcpu_arch *arch = &vcpu->arch;
enum emulation_result er = EMULATE_DONE;
if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
/* save old pc */
kvm_write_c0_guest_epc(cop0, arch->pc);
kvm_set_c0_guest_status(cop0, ST0_EXL);
if (cause & CAUSEF_BD)
kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
else
kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
kvm_debug("Delivering RI @ pc %#lx\n", arch->pc);
kvm_change_c0_guest_cause(cop0, (0xff),
(T_RES_INST << CAUSEB_EXCCODE));
/* Set PC to the exception entry point */
arch->pc = KVM_GUEST_KSEG0 + 0x180;
} else {
kvm_err("Trying to deliver RI when EXL is already set\n");
er = EMULATE_FAIL;
}
return er;
}
enum emulation_result
kvm_mips_emulate_bp_exc(unsigned long cause, uint32_t *opc,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
struct kvm_vcpu_arch *arch = &vcpu->arch;
enum emulation_result er = EMULATE_DONE;
if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
/* save old pc */
kvm_write_c0_guest_epc(cop0, arch->pc);
kvm_set_c0_guest_status(cop0, ST0_EXL);
if (cause & CAUSEF_BD)
kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
else
kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
kvm_debug("Delivering BP @ pc %#lx\n", arch->pc);
kvm_change_c0_guest_cause(cop0, (0xff),
(T_BREAK << CAUSEB_EXCCODE));
/* Set PC to the exception entry point */
arch->pc = KVM_GUEST_KSEG0 + 0x180;
} else {
printk("Trying to deliver BP when EXL is already set\n");
er = EMULATE_FAIL;
}
return er;
}
/*
* ll/sc, rdhwr, sync emulation
*/
#define OPCODE 0xfc000000
#define BASE 0x03e00000
#define RT 0x001f0000
#define OFFSET 0x0000ffff
#define LL 0xc0000000
#define SC 0xe0000000
#define SPEC0 0x00000000
#define SPEC3 0x7c000000
#define RD 0x0000f800
#define FUNC 0x0000003f
#define SYNC 0x0000000f
#define RDHWR 0x0000003b
enum emulation_result
kvm_mips_handle_ri(unsigned long cause, uint32_t *opc,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
struct kvm_vcpu_arch *arch = &vcpu->arch;
enum emulation_result er = EMULATE_DONE;
unsigned long curr_pc;
uint32_t inst;
/*
* Update PC and hold onto current PC in case there is
* an error and we want to rollback the PC
*/
curr_pc = vcpu->arch.pc;
er = update_pc(vcpu, cause);
if (er == EMULATE_FAIL)
return er;
/*
* Fetch the instruction.
*/
if (cause & CAUSEF_BD)
opc += 1;
inst = kvm_get_inst(opc, vcpu);
if (inst == KVM_INVALID_INST) {
printk("%s: Cannot get inst @ %p\n", __func__, opc);
return EMULATE_FAIL;
}
if ((inst & OPCODE) == SPEC3 && (inst & FUNC) == RDHWR) {
MIPS: KVM: Consult HWREna before emulating RDHWR The ability to read hardware registers from userland with the RDHWR instruction should depend upon the corresponding bit of the HWREna register being set, otherwise a reserved instruction exception should be generated. However KVM's current emulation ignores the guest's HWREna and always emulates RDHWR instructions even if the guest OS has disallowed them. Therefore rework the RDHWR emulation code to check for privilege or the corresponding bit in the guest HWREna bit. Also remove the #if 0 case for the UserLocal register. I presume it was there for debug purposes but it seems unnecessary now that the guest can control whether it causes a guest exception. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-03-14 13:06:09 +00:00
int usermode = !KVM_GUEST_KERNEL_MODE(vcpu);
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
int rd = (inst & RD) >> 11;
int rt = (inst & RT) >> 16;
MIPS: KVM: Consult HWREna before emulating RDHWR The ability to read hardware registers from userland with the RDHWR instruction should depend upon the corresponding bit of the HWREna register being set, otherwise a reserved instruction exception should be generated. However KVM's current emulation ignores the guest's HWREna and always emulates RDHWR instructions even if the guest OS has disallowed them. Therefore rework the RDHWR emulation code to check for privilege or the corresponding bit in the guest HWREna bit. Also remove the #if 0 case for the UserLocal register. I presume it was there for debug purposes but it seems unnecessary now that the guest can control whether it causes a guest exception. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-03-14 13:06:09 +00:00
/* If usermode, check RDHWR rd is allowed by guest HWREna */
if (usermode && !(kvm_read_c0_guest_hwrena(cop0) & BIT(rd))) {
kvm_debug("RDHWR %#x disallowed by HWREna @ %p\n",
rd, opc);
goto emulate_ri;
}
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
switch (rd) {
case 0: /* CPU number */
arch->gprs[rt] = 0;
break;
case 1: /* SYNCI length */
arch->gprs[rt] = min(current_cpu_data.dcache.linesz,
current_cpu_data.icache.linesz);
break;
case 2: /* Read count register */
MIPS: KVM: Rewrite count/compare timer emulation Previously the emulation of the CPU timer was just enough to get a Linux guest running but some shortcuts were taken: - The guest timer interrupt was hard coded to always happen every 10 ms rather than being timed to when CP0_Count would match CP0_Compare. - The guest's CP0_Count register was based on the host's CP0_Count register. This isn't very portable and fails on cores without a CP_Count register implemented such as Ingenic XBurst. It also meant that the guest's CP0_Cause.DC bit to disable the CP0_Count register took no effect. - The guest's CP0_Count register was emulated by just dividing the host's CP0_Count register by 4. This resulted in continuity problems when used as a clock source, since when the host CP0_Count overflows from 0x7fffffff to 0x80000000, the guest CP0_Count transitions discontinuously from 0x1fffffff to 0xe0000000. Therefore rewrite & fix emulation of the guest timer based on the monotonic kernel time (i.e. ktime_get()). Internally a 32-bit count_bias value is added to the frequency scaled nanosecond monotonic time to get the guest's CP0_Count. The frequency of the timer is initialised to 100MHz and cannot yet be changed, but a later patch will allow the frequency to be configured via the KVM_{GET,SET}_ONE_REG ioctl interface. The timer can now be stopped via the CP0_Cause.DC bit (by the guest or via the KVM_SET_ONE_REG ioctl interface), at which point the current CP0_Count is stored and can be read directly. When it is restarted the bias is recalculated such that the CP0_Count value is continuous. Due to the nature of hrtimer interrupts any read of the guest's CP0_Count register while it is running triggers a check for whether the hrtimer has expired, so that the guest/userland cannot observe the CP0_Count passing CP0_Compare without queuing a timer interrupt. This is also taken advantage of when stopping the timer to ensure that a pending timer interrupt is queued. This replaces the implementation of: - Guest read of CP0_Count - Guest write of CP0_Count - Guest write of CP0_Compare - Guest write of CP0_Cause - Guest read of HWR 2 (CC) with RDHWR - Host read of CP0_Count via KVM_GET_ONE_REG ioctl interface - Host write of CP0_Count via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Compare via KVM_SET_ONE_REG ioctl interface - Host write of CP0_Cause via KVM_SET_ONE_REG ioctl interface Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Sanjay Lal <sanjayl@kymasys.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-05-29 09:16:35 +00:00
arch->gprs[rt] = kvm_mips_read_count(vcpu);
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
break;
case 3: /* Count register resolution */
switch (current_cpu_data.cputype) {
case CPU_20KC:
case CPU_25KF:
arch->gprs[rt] = 1;
break;
default:
arch->gprs[rt] = 2;
}
break;
case 29:
arch->gprs[rt] = kvm_read_c0_guest_userlocal(cop0);
break;
default:
MIPS: KVM: Pass reserved instruction exceptions to guest Previously a reserved instruction exception while in guest code would cause a KVM internal error if kvm_mips_handle_ri() didn't recognise the instruction (including a RDHWR from an unrecognised hardware register). However the guest OS should really have the opportunity to catch the exception so that it can take the appropriate actions such as sending a SIGILL to the guest user process or emulating the instruction itself. Therefore in these cases emulate a guest RI exception and only return EMULATE_FAIL if that fails, being careful to revert the PC first in case the exception occurred in a branch delay slot in which case the PC will already point to the branch target. Also turn the printk messages relating to these cases into kvm_debug messages so that they aren't usually visible. This allows crashme to run in the guest without killing the entire VM. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-03-14 13:06:07 +00:00
kvm_debug("RDHWR %#x not supported @ %p\n", rd, opc);
MIPS: KVM: Consult HWREna before emulating RDHWR The ability to read hardware registers from userland with the RDHWR instruction should depend upon the corresponding bit of the HWREna register being set, otherwise a reserved instruction exception should be generated. However KVM's current emulation ignores the guest's HWREna and always emulates RDHWR instructions even if the guest OS has disallowed them. Therefore rework the RDHWR emulation code to check for privilege or the corresponding bit in the guest HWREna bit. Also remove the #if 0 case for the UserLocal register. I presume it was there for debug purposes but it seems unnecessary now that the guest can control whether it causes a guest exception. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-03-14 13:06:09 +00:00
goto emulate_ri;
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
}
} else {
MIPS: KVM: Pass reserved instruction exceptions to guest Previously a reserved instruction exception while in guest code would cause a KVM internal error if kvm_mips_handle_ri() didn't recognise the instruction (including a RDHWR from an unrecognised hardware register). However the guest OS should really have the opportunity to catch the exception so that it can take the appropriate actions such as sending a SIGILL to the guest user process or emulating the instruction itself. Therefore in these cases emulate a guest RI exception and only return EMULATE_FAIL if that fails, being careful to revert the PC first in case the exception occurred in a branch delay slot in which case the PC will already point to the branch target. Also turn the printk messages relating to these cases into kvm_debug messages so that they aren't usually visible. This allows crashme to run in the guest without killing the entire VM. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-03-14 13:06:07 +00:00
kvm_debug("Emulate RI not supported @ %p: %#x\n", opc, inst);
MIPS: KVM: Consult HWREna before emulating RDHWR The ability to read hardware registers from userland with the RDHWR instruction should depend upon the corresponding bit of the HWREna register being set, otherwise a reserved instruction exception should be generated. However KVM's current emulation ignores the guest's HWREna and always emulates RDHWR instructions even if the guest OS has disallowed them. Therefore rework the RDHWR emulation code to check for privilege or the corresponding bit in the guest HWREna bit. Also remove the #if 0 case for the UserLocal register. I presume it was there for debug purposes but it seems unnecessary now that the guest can control whether it causes a guest exception. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-03-14 13:06:09 +00:00
goto emulate_ri;
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
}
MIPS: KVM: Consult HWREna before emulating RDHWR The ability to read hardware registers from userland with the RDHWR instruction should depend upon the corresponding bit of the HWREna register being set, otherwise a reserved instruction exception should be generated. However KVM's current emulation ignores the guest's HWREna and always emulates RDHWR instructions even if the guest OS has disallowed them. Therefore rework the RDHWR emulation code to check for privilege or the corresponding bit in the guest HWREna bit. Also remove the #if 0 case for the UserLocal register. I presume it was there for debug purposes but it seems unnecessary now that the guest can control whether it causes a guest exception. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-03-14 13:06:09 +00:00
return EMULATE_DONE;
emulate_ri:
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
/*
MIPS: KVM: Consult HWREna before emulating RDHWR The ability to read hardware registers from userland with the RDHWR instruction should depend upon the corresponding bit of the HWREna register being set, otherwise a reserved instruction exception should be generated. However KVM's current emulation ignores the guest's HWREna and always emulates RDHWR instructions even if the guest OS has disallowed them. Therefore rework the RDHWR emulation code to check for privilege or the corresponding bit in the guest HWREna bit. Also remove the #if 0 case for the UserLocal register. I presume it was there for debug purposes but it seems unnecessary now that the guest can control whether it causes a guest exception. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-03-14 13:06:09 +00:00
* Rollback PC (if in branch delay slot then the PC already points to
* branch target), and pass the RI exception to the guest OS.
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
*/
MIPS: KVM: Consult HWREna before emulating RDHWR The ability to read hardware registers from userland with the RDHWR instruction should depend upon the corresponding bit of the HWREna register being set, otherwise a reserved instruction exception should be generated. However KVM's current emulation ignores the guest's HWREna and always emulates RDHWR instructions even if the guest OS has disallowed them. Therefore rework the RDHWR emulation code to check for privilege or the corresponding bit in the guest HWREna bit. Also remove the #if 0 case for the UserLocal register. I presume it was there for debug purposes but it seems unnecessary now that the guest can control whether it causes a guest exception. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sanjay Lal <sanjayl@kymasys.com> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-03-14 13:06:09 +00:00
vcpu->arch.pc = curr_pc;
return kvm_mips_emulate_ri_exc(cause, opc, run, vcpu);
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
}
enum emulation_result
kvm_mips_complete_mmio_load(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
unsigned long *gpr = &vcpu->arch.gprs[vcpu->arch.io_gpr];
enum emulation_result er = EMULATE_DONE;
unsigned long curr_pc;
if (run->mmio.len > sizeof(*gpr)) {
printk("Bad MMIO length: %d", run->mmio.len);
er = EMULATE_FAIL;
goto done;
}
/*
* Update PC and hold onto current PC in case there is
* an error and we want to rollback the PC
*/
curr_pc = vcpu->arch.pc;
er = update_pc(vcpu, vcpu->arch.pending_load_cause);
if (er == EMULATE_FAIL)
return er;
switch (run->mmio.len) {
case 4:
*gpr = *(int32_t *) run->mmio.data;
break;
case 2:
if (vcpu->mmio_needed == 2)
*gpr = *(int16_t *) run->mmio.data;
else
*gpr = *(int16_t *) run->mmio.data;
break;
case 1:
if (vcpu->mmio_needed == 2)
*gpr = *(int8_t *) run->mmio.data;
else
*gpr = *(u8 *) run->mmio.data;
break;
}
if (vcpu->arch.pending_load_cause & CAUSEF_BD)
kvm_debug
("[%#lx] Completing %d byte BD Load to gpr %d (0x%08lx) type %d\n",
vcpu->arch.pc, run->mmio.len, vcpu->arch.io_gpr, *gpr,
vcpu->mmio_needed);
done:
return er;
}
static enum emulation_result
kvm_mips_emulate_exc(unsigned long cause, uint32_t *opc,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
uint32_t exccode = (cause >> CAUSEB_EXCCODE) & 0x1f;
struct mips_coproc *cop0 = vcpu->arch.cop0;
struct kvm_vcpu_arch *arch = &vcpu->arch;
enum emulation_result er = EMULATE_DONE;
if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
/* save old pc */
kvm_write_c0_guest_epc(cop0, arch->pc);
kvm_set_c0_guest_status(cop0, ST0_EXL);
if (cause & CAUSEF_BD)
kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
else
kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
kvm_change_c0_guest_cause(cop0, (0xff),
(exccode << CAUSEB_EXCCODE));
/* Set PC to the exception entry point */
arch->pc = KVM_GUEST_KSEG0 + 0x180;
kvm_write_c0_guest_badvaddr(cop0, vcpu->arch.host_cp0_badvaddr);
kvm_debug("Delivering EXC %d @ pc %#lx, badVaddr: %#lx\n",
exccode, kvm_read_c0_guest_epc(cop0),
kvm_read_c0_guest_badvaddr(cop0));
} else {
printk("Trying to deliver EXC when EXL is already set\n");
er = EMULATE_FAIL;
}
return er;
}
enum emulation_result
kvm_mips_check_privilege(unsigned long cause, uint32_t *opc,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
enum emulation_result er = EMULATE_DONE;
uint32_t exccode = (cause >> CAUSEB_EXCCODE) & 0x1f;
unsigned long badvaddr = vcpu->arch.host_cp0_badvaddr;
int usermode = !KVM_GUEST_KERNEL_MODE(vcpu);
if (usermode) {
switch (exccode) {
case T_INT:
case T_SYSCALL:
case T_BREAK:
case T_RES_INST:
break;
case T_COP_UNUSABLE:
if (((cause & CAUSEF_CE) >> CAUSEB_CE) == 0)
er = EMULATE_PRIV_FAIL;
break;
case T_TLB_MOD:
break;
case T_TLB_LD_MISS:
/* We we are accessing Guest kernel space, then send an address error exception to the guest */
if (badvaddr >= (unsigned long) KVM_GUEST_KSEG0) {
printk("%s: LD MISS @ %#lx\n", __func__,
badvaddr);
cause &= ~0xff;
cause |= (T_ADDR_ERR_LD << CAUSEB_EXCCODE);
er = EMULATE_PRIV_FAIL;
}
break;
case T_TLB_ST_MISS:
/* We we are accessing Guest kernel space, then send an address error exception to the guest */
if (badvaddr >= (unsigned long) KVM_GUEST_KSEG0) {
printk("%s: ST MISS @ %#lx\n", __func__,
badvaddr);
cause &= ~0xff;
cause |= (T_ADDR_ERR_ST << CAUSEB_EXCCODE);
er = EMULATE_PRIV_FAIL;
}
break;
case T_ADDR_ERR_ST:
printk("%s: address error ST @ %#lx\n", __func__,
badvaddr);
if ((badvaddr & PAGE_MASK) == KVM_GUEST_COMMPAGE_ADDR) {
cause &= ~0xff;
cause |= (T_TLB_ST_MISS << CAUSEB_EXCCODE);
}
er = EMULATE_PRIV_FAIL;
break;
case T_ADDR_ERR_LD:
printk("%s: address error LD @ %#lx\n", __func__,
badvaddr);
if ((badvaddr & PAGE_MASK) == KVM_GUEST_COMMPAGE_ADDR) {
cause &= ~0xff;
cause |= (T_TLB_LD_MISS << CAUSEB_EXCCODE);
}
er = EMULATE_PRIV_FAIL;
break;
default:
er = EMULATE_PRIV_FAIL;
break;
}
}
if (er == EMULATE_PRIV_FAIL) {
kvm_mips_emulate_exc(cause, opc, run, vcpu);
}
return er;
}
/* User Address (UA) fault, this could happen if
* (1) TLB entry not present/valid in both Guest and shadow host TLBs, in this
* case we pass on the fault to the guest kernel and let it handle it.
* (2) TLB entry is present in the Guest TLB but not in the shadow, in this
* case we inject the TLB from the Guest TLB into the shadow host TLB
*/
enum emulation_result
kvm_mips_handle_tlbmiss(unsigned long cause, uint32_t *opc,
struct kvm_run *run, struct kvm_vcpu *vcpu)
{
enum emulation_result er = EMULATE_DONE;
uint32_t exccode = (cause >> CAUSEB_EXCCODE) & 0x1f;
unsigned long va = vcpu->arch.host_cp0_badvaddr;
int index;
kvm_debug("kvm_mips_handle_tlbmiss: badvaddr: %#lx, entryhi: %#lx\n",
vcpu->arch.host_cp0_badvaddr, vcpu->arch.host_cp0_entryhi);
/* KVM would not have got the exception if this entry was valid in the shadow host TLB
* Check the Guest TLB, if the entry is not there then send the guest an
* exception. The guest exc handler should then inject an entry into the
* guest TLB
*/
index = kvm_mips_guest_tlb_lookup(vcpu,
(va & VPN2_MASK) |
Revert "MIPS: Allow ASID size to be determined at boot time." This reverts commit d532f3d26716a39dfd4b88d687bd344fbe77e390. The original commit has several problems: 1) Doesn't work with 64-bit kernels. 2) Calls TLBMISS_HANDLER_SETUP() before the code is generated. 3) Calls TLBMISS_HANDLER_SETUP() twice in per_cpu_trap_init() when only one call is needed. [ralf@linux-mips.org: Also revert the bits of the ASID patch which were hidden in the KVM merge.] Signed-off-by: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Cc: "Steven J. Hill" <Steven.Hill@imgtec.com> Cc: David Daney <david.daney@cavium.com> Patchwork: https://patchwork.linux-mips.org/patch/5242/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-05-13 20:56:44 +00:00
(kvm_read_c0_guest_entryhi
(vcpu->arch.cop0) & ASID_MASK));
KVM/MIPS32: Privileged instruction/target branch emulation. - The Guest kernel is run in UM and privileged instructions cause a trap. - If the instruction causing the trap is in a branch delay slot, the branch needs to be emulated to figure out the PC @ which the guest will resume execution. Signed-off-by: Sanjay Lal <sanjayl@kymasys.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-11-22 02:34:04 +00:00
if (index < 0) {
if (exccode == T_TLB_LD_MISS) {
er = kvm_mips_emulate_tlbmiss_ld(cause, opc, run, vcpu);
} else if (exccode == T_TLB_ST_MISS) {
er = kvm_mips_emulate_tlbmiss_st(cause, opc, run, vcpu);
} else {
printk("%s: invalid exc code: %d\n", __func__, exccode);
er = EMULATE_FAIL;
}
} else {
struct kvm_mips_tlb *tlb = &vcpu->arch.guest_tlb[index];
/* Check if the entry is valid, if not then setup a TLB invalid exception to the guest */
if (!TLB_IS_VALID(*tlb, va)) {
if (exccode == T_TLB_LD_MISS) {
er = kvm_mips_emulate_tlbinv_ld(cause, opc, run,
vcpu);
} else if (exccode == T_TLB_ST_MISS) {
er = kvm_mips_emulate_tlbinv_st(cause, opc, run,
vcpu);
} else {
printk("%s: invalid exc code: %d\n", __func__,
exccode);
er = EMULATE_FAIL;
}
} else {
#ifdef DEBUG
kvm_debug
("Injecting hi: %#lx, lo0: %#lx, lo1: %#lx into shadow host TLB\n",
tlb->tlb_hi, tlb->tlb_lo0, tlb->tlb_lo1);
#endif
/* OK we have a Guest TLB entry, now inject it into the shadow host TLB */
kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb, NULL,
NULL);
}
}
return er;
}
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