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linux/arch/powerpc/kvm/booke_guest.c
Hollis Blanchard 49dd2c4928 KVM: powerpc: Map guest userspace with TID=0 mappings 
When we use TID=N userspace mappings, we must ensure that kernel mappings have
been destroyed when entering userspace. Using TID=1/TID=0 for kernel/user
mappings and running userspace with PID=0 means that userspace can't access the
kernel mappings, but the kernel can directly access userspace.

The net is that we don't need to flush the TLB on privilege switches, but we do
on guest context switches (which are far more infrequent). Guest boot time
performance improvement: about 30%.

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-10-15 10:15:16 +02:00

606 lines
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/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* Copyright IBM Corp. 2007
*
* Authors: Hollis Blanchard <hollisb@us.ibm.com>
* Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
*/
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kvm_host.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <asm/cputable.h>
#include <asm/uaccess.h>
#include <asm/kvm_ppc.h>
#include "44x_tlb.h"
#define VM_STAT(x) offsetof(struct kvm, stat.x), KVM_STAT_VM
#define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU
struct kvm_stats_debugfs_item debugfs_entries[] = {
{ "exits", VCPU_STAT(sum_exits) },
{ "mmio", VCPU_STAT(mmio_exits) },
{ "dcr", VCPU_STAT(dcr_exits) },
{ "sig", VCPU_STAT(signal_exits) },
{ "light", VCPU_STAT(light_exits) },
{ "itlb_r", VCPU_STAT(itlb_real_miss_exits) },
{ "itlb_v", VCPU_STAT(itlb_virt_miss_exits) },
{ "dtlb_r", VCPU_STAT(dtlb_real_miss_exits) },
{ "dtlb_v", VCPU_STAT(dtlb_virt_miss_exits) },
{ "sysc", VCPU_STAT(syscall_exits) },
{ "isi", VCPU_STAT(isi_exits) },
{ "dsi", VCPU_STAT(dsi_exits) },
{ "inst_emu", VCPU_STAT(emulated_inst_exits) },
{ "dec", VCPU_STAT(dec_exits) },
{ "ext_intr", VCPU_STAT(ext_intr_exits) },
{ "halt_wakeup", VCPU_STAT(halt_wakeup) },
{ NULL }
};
static const u32 interrupt_msr_mask[16] = {
[BOOKE_INTERRUPT_CRITICAL] = MSR_ME,
[BOOKE_INTERRUPT_MACHINE_CHECK] = 0,
[BOOKE_INTERRUPT_DATA_STORAGE] = MSR_CE|MSR_ME|MSR_DE,
[BOOKE_INTERRUPT_INST_STORAGE] = MSR_CE|MSR_ME|MSR_DE,
[BOOKE_INTERRUPT_EXTERNAL] = MSR_CE|MSR_ME|MSR_DE,
[BOOKE_INTERRUPT_ALIGNMENT] = MSR_CE|MSR_ME|MSR_DE,
[BOOKE_INTERRUPT_PROGRAM] = MSR_CE|MSR_ME|MSR_DE,
[BOOKE_INTERRUPT_FP_UNAVAIL] = MSR_CE|MSR_ME|MSR_DE,
[BOOKE_INTERRUPT_SYSCALL] = MSR_CE|MSR_ME|MSR_DE,
[BOOKE_INTERRUPT_AP_UNAVAIL] = MSR_CE|MSR_ME|MSR_DE,
[BOOKE_INTERRUPT_DECREMENTER] = MSR_CE|MSR_ME|MSR_DE,
[BOOKE_INTERRUPT_FIT] = MSR_CE|MSR_ME|MSR_DE,
[BOOKE_INTERRUPT_WATCHDOG] = MSR_ME,
[BOOKE_INTERRUPT_DTLB_MISS] = MSR_CE|MSR_ME|MSR_DE,
[BOOKE_INTERRUPT_ITLB_MISS] = MSR_CE|MSR_ME|MSR_DE,
[BOOKE_INTERRUPT_DEBUG] = MSR_ME,
};
const unsigned char exception_priority[] = {
[BOOKE_INTERRUPT_DATA_STORAGE] = 0,
[BOOKE_INTERRUPT_INST_STORAGE] = 1,
[BOOKE_INTERRUPT_ALIGNMENT] = 2,
[BOOKE_INTERRUPT_PROGRAM] = 3,
[BOOKE_INTERRUPT_FP_UNAVAIL] = 4,
[BOOKE_INTERRUPT_SYSCALL] = 5,
[BOOKE_INTERRUPT_AP_UNAVAIL] = 6,
[BOOKE_INTERRUPT_DTLB_MISS] = 7,
[BOOKE_INTERRUPT_ITLB_MISS] = 8,
[BOOKE_INTERRUPT_MACHINE_CHECK] = 9,
[BOOKE_INTERRUPT_DEBUG] = 10,
[BOOKE_INTERRUPT_CRITICAL] = 11,
[BOOKE_INTERRUPT_WATCHDOG] = 12,
[BOOKE_INTERRUPT_EXTERNAL] = 13,
[BOOKE_INTERRUPT_FIT] = 14,
[BOOKE_INTERRUPT_DECREMENTER] = 15,
};
const unsigned char priority_exception[] = {
BOOKE_INTERRUPT_DATA_STORAGE,
BOOKE_INTERRUPT_INST_STORAGE,
BOOKE_INTERRUPT_ALIGNMENT,
BOOKE_INTERRUPT_PROGRAM,
BOOKE_INTERRUPT_FP_UNAVAIL,
BOOKE_INTERRUPT_SYSCALL,
BOOKE_INTERRUPT_AP_UNAVAIL,
BOOKE_INTERRUPT_DTLB_MISS,
BOOKE_INTERRUPT_ITLB_MISS,
BOOKE_INTERRUPT_MACHINE_CHECK,
BOOKE_INTERRUPT_DEBUG,
BOOKE_INTERRUPT_CRITICAL,
BOOKE_INTERRUPT_WATCHDOG,
BOOKE_INTERRUPT_EXTERNAL,
BOOKE_INTERRUPT_FIT,
BOOKE_INTERRUPT_DECREMENTER,
};
void kvmppc_dump_tlbs(struct kvm_vcpu *vcpu)
{
struct tlbe *tlbe;
int i;
printk("vcpu %d TLB dump:\n", vcpu->vcpu_id);
printk("| %2s | %3s | %8s | %8s | %8s |\n",
"nr", "tid", "word0", "word1", "word2");
for (i = 0; i < PPC44x_TLB_SIZE; i++) {
tlbe = &vcpu->arch.guest_tlb[i];
if (tlbe->word0 & PPC44x_TLB_VALID)
printk(" G%2d | %02X | %08X | %08X | %08X |\n",
i, tlbe->tid, tlbe->word0, tlbe->word1,
tlbe->word2);
}
for (i = 0; i < PPC44x_TLB_SIZE; i++) {
tlbe = &vcpu->arch.shadow_tlb[i];
if (tlbe->word0 & PPC44x_TLB_VALID)
printk(" S%2d | %02X | %08X | %08X | %08X |\n",
i, tlbe->tid, tlbe->word0, tlbe->word1,
tlbe->word2);
}
}
/* TODO: use vcpu_printf() */
void kvmppc_dump_vcpu(struct kvm_vcpu *vcpu)
{
int i;
printk("pc: %08x msr: %08x\n", vcpu->arch.pc, vcpu->arch.msr);
printk("lr: %08x ctr: %08x\n", vcpu->arch.lr, vcpu->arch.ctr);
printk("srr0: %08x srr1: %08x\n", vcpu->arch.srr0, vcpu->arch.srr1);
printk("exceptions: %08lx\n", vcpu->arch.pending_exceptions);
for (i = 0; i < 32; i += 4) {
printk("gpr%02d: %08x %08x %08x %08x\n", i,
vcpu->arch.gpr[i],
vcpu->arch.gpr[i+1],
vcpu->arch.gpr[i+2],
vcpu->arch.gpr[i+3]);
}
}
/* Check if we are ready to deliver the interrupt */
static int kvmppc_can_deliver_interrupt(struct kvm_vcpu *vcpu, int interrupt)
{
int r;
switch (interrupt) {
case BOOKE_INTERRUPT_CRITICAL:
r = vcpu->arch.msr & MSR_CE;
break;
case BOOKE_INTERRUPT_MACHINE_CHECK:
r = vcpu->arch.msr & MSR_ME;
break;
case BOOKE_INTERRUPT_EXTERNAL:
r = vcpu->arch.msr & MSR_EE;
break;
case BOOKE_INTERRUPT_DECREMENTER:
r = vcpu->arch.msr & MSR_EE;
break;
case BOOKE_INTERRUPT_FIT:
r = vcpu->arch.msr & MSR_EE;
break;
case BOOKE_INTERRUPT_WATCHDOG:
r = vcpu->arch.msr & MSR_CE;
break;
case BOOKE_INTERRUPT_DEBUG:
r = vcpu->arch.msr & MSR_DE;
break;
default:
r = 1;
}
return r;
}
static void kvmppc_deliver_interrupt(struct kvm_vcpu *vcpu, int interrupt)
{
switch (interrupt) {
case BOOKE_INTERRUPT_DECREMENTER:
vcpu->arch.tsr |= TSR_DIS;
break;
}
vcpu->arch.srr0 = vcpu->arch.pc;
vcpu->arch.srr1 = vcpu->arch.msr;
vcpu->arch.pc = vcpu->arch.ivpr | vcpu->arch.ivor[interrupt];
kvmppc_set_msr(vcpu, vcpu->arch.msr & interrupt_msr_mask[interrupt]);
}
/* Check pending exceptions and deliver one, if possible. */
void kvmppc_check_and_deliver_interrupts(struct kvm_vcpu *vcpu)
{
unsigned long *pending = &vcpu->arch.pending_exceptions;
unsigned int exception;
unsigned int priority;
priority = find_first_bit(pending, BITS_PER_BYTE * sizeof(*pending));
while (priority <= BOOKE_MAX_INTERRUPT) {
exception = priority_exception[priority];
if (kvmppc_can_deliver_interrupt(vcpu, exception)) {
kvmppc_clear_exception(vcpu, exception);
kvmppc_deliver_interrupt(vcpu, exception);
break;
}
priority = find_next_bit(pending,
BITS_PER_BYTE * sizeof(*pending),
priority + 1);
}
}
/**
* kvmppc_handle_exit
*
* Return value is in the form (errcode<<2 | RESUME_FLAG_HOST | RESUME_FLAG_NV)
*/
int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
unsigned int exit_nr)
{
enum emulation_result er;
int r = RESUME_HOST;
local_irq_enable();
run->exit_reason = KVM_EXIT_UNKNOWN;
run->ready_for_interrupt_injection = 1;
switch (exit_nr) {
case BOOKE_INTERRUPT_MACHINE_CHECK:
printk("MACHINE CHECK: %lx\n", mfspr(SPRN_MCSR));
kvmppc_dump_vcpu(vcpu);
r = RESUME_HOST;
break;
case BOOKE_INTERRUPT_EXTERNAL:
case BOOKE_INTERRUPT_DECREMENTER:
/* Since we switched IVPR back to the host's value, the host
* handled this interrupt the moment we enabled interrupts.
* Now we just offer it a chance to reschedule the guest. */
/* XXX At this point the TLB still holds our shadow TLB, so if
* we do reschedule the host will fault over it. Perhaps we
* should politely restore the host's entries to minimize
* misses before ceding control. */
if (need_resched())
cond_resched();
if (exit_nr == BOOKE_INTERRUPT_DECREMENTER)
vcpu->stat.dec_exits++;
else
vcpu->stat.ext_intr_exits++;
r = RESUME_GUEST;
break;
case BOOKE_INTERRUPT_PROGRAM:
if (vcpu->arch.msr & MSR_PR) {
/* Program traps generated by user-level software must be handled
* by the guest kernel. */
vcpu->arch.esr = vcpu->arch.fault_esr;
kvmppc_queue_exception(vcpu, BOOKE_INTERRUPT_PROGRAM);
r = RESUME_GUEST;
break;
}
er = kvmppc_emulate_instruction(run, vcpu);
switch (er) {
case EMULATE_DONE:
/* Future optimization: only reload non-volatiles if
* they were actually modified by emulation. */
vcpu->stat.emulated_inst_exits++;
r = RESUME_GUEST_NV;
break;
case EMULATE_DO_DCR:
run->exit_reason = KVM_EXIT_DCR;
r = RESUME_HOST;
break;
case EMULATE_FAIL:
/* XXX Deliver Program interrupt to guest. */
printk(KERN_CRIT "%s: emulation at %x failed (%08x)\n",
__func__, vcpu->arch.pc, vcpu->arch.last_inst);
/* For debugging, encode the failing instruction and
* report it to userspace. */
run->hw.hardware_exit_reason = ~0ULL << 32;
run->hw.hardware_exit_reason |= vcpu->arch.last_inst;
r = RESUME_HOST;
break;
default:
BUG();
}
break;
case BOOKE_INTERRUPT_FP_UNAVAIL:
kvmppc_queue_exception(vcpu, exit_nr);
r = RESUME_GUEST;
break;
case BOOKE_INTERRUPT_DATA_STORAGE:
vcpu->arch.dear = vcpu->arch.fault_dear;
vcpu->arch.esr = vcpu->arch.fault_esr;
kvmppc_queue_exception(vcpu, exit_nr);
vcpu->stat.dsi_exits++;
r = RESUME_GUEST;
break;
case BOOKE_INTERRUPT_INST_STORAGE:
vcpu->arch.esr = vcpu->arch.fault_esr;
kvmppc_queue_exception(vcpu, exit_nr);
vcpu->stat.isi_exits++;
r = RESUME_GUEST;
break;
case BOOKE_INTERRUPT_SYSCALL:
kvmppc_queue_exception(vcpu, exit_nr);
vcpu->stat.syscall_exits++;
r = RESUME_GUEST;
break;
case BOOKE_INTERRUPT_DTLB_MISS: {
struct tlbe *gtlbe;
unsigned long eaddr = vcpu->arch.fault_dear;
gfn_t gfn;
/* Check the guest TLB. */
gtlbe = kvmppc_44x_dtlb_search(vcpu, eaddr);
if (!gtlbe) {
/* The guest didn't have a mapping for it. */
kvmppc_queue_exception(vcpu, exit_nr);
vcpu->arch.dear = vcpu->arch.fault_dear;
vcpu->arch.esr = vcpu->arch.fault_esr;
vcpu->stat.dtlb_real_miss_exits++;
r = RESUME_GUEST;
break;
}
vcpu->arch.paddr_accessed = tlb_xlate(gtlbe, eaddr);
gfn = vcpu->arch.paddr_accessed >> PAGE_SHIFT;
if (kvm_is_visible_gfn(vcpu->kvm, gfn)) {
/* The guest TLB had a mapping, but the shadow TLB
* didn't, and it is RAM. This could be because:
* a) the entry is mapping the host kernel, or
* b) the guest used a large mapping which we're faking
* Either way, we need to satisfy the fault without
* invoking the guest. */
kvmppc_mmu_map(vcpu, eaddr, gfn, gtlbe->tid,
gtlbe->word2);
vcpu->stat.dtlb_virt_miss_exits++;
r = RESUME_GUEST;
} else {
/* Guest has mapped and accessed a page which is not
* actually RAM. */
r = kvmppc_emulate_mmio(run, vcpu);
}
break;
}
case BOOKE_INTERRUPT_ITLB_MISS: {
struct tlbe *gtlbe;
unsigned long eaddr = vcpu->arch.pc;
gfn_t gfn;
r = RESUME_GUEST;
/* Check the guest TLB. */
gtlbe = kvmppc_44x_itlb_search(vcpu, eaddr);
if (!gtlbe) {
/* The guest didn't have a mapping for it. */
kvmppc_queue_exception(vcpu, exit_nr);
vcpu->stat.itlb_real_miss_exits++;
break;
}
vcpu->stat.itlb_virt_miss_exits++;
gfn = tlb_xlate(gtlbe, eaddr) >> PAGE_SHIFT;
if (kvm_is_visible_gfn(vcpu->kvm, gfn)) {
/* The guest TLB had a mapping, but the shadow TLB
* didn't. This could be because:
* a) the entry is mapping the host kernel, or
* b) the guest used a large mapping which we're faking
* Either way, we need to satisfy the fault without
* invoking the guest. */
kvmppc_mmu_map(vcpu, eaddr, gfn, gtlbe->tid,
gtlbe->word2);
} else {
/* Guest mapped and leaped at non-RAM! */
kvmppc_queue_exception(vcpu,
BOOKE_INTERRUPT_MACHINE_CHECK);
}
break;
}
case BOOKE_INTERRUPT_DEBUG: {
u32 dbsr;
vcpu->arch.pc = mfspr(SPRN_CSRR0);
/* clear IAC events in DBSR register */
dbsr = mfspr(SPRN_DBSR);
dbsr &= DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4;
mtspr(SPRN_DBSR, dbsr);
run->exit_reason = KVM_EXIT_DEBUG;
r = RESUME_HOST;
break;
}
default:
printk(KERN_EMERG "exit_nr %d\n", exit_nr);
BUG();
}
local_irq_disable();
kvmppc_check_and_deliver_interrupts(vcpu);
/* Do some exit accounting. */
vcpu->stat.sum_exits++;
if (!(r & RESUME_HOST)) {
/* To avoid clobbering exit_reason, only check for signals if
* we aren't already exiting to userspace for some other
* reason. */
if (signal_pending(current)) {
run->exit_reason = KVM_EXIT_INTR;
r = (-EINTR << 2) | RESUME_HOST | (r & RESUME_FLAG_NV);
vcpu->stat.signal_exits++;
} else {
vcpu->stat.light_exits++;
}
} else {
switch (run->exit_reason) {
case KVM_EXIT_MMIO:
vcpu->stat.mmio_exits++;
break;
case KVM_EXIT_DCR:
vcpu->stat.dcr_exits++;
break;
case KVM_EXIT_INTR:
vcpu->stat.signal_exits++;
break;
}
}
return r;
}
/* Initial guest state: 16MB mapping 0 -> 0, PC = 0, MSR = 0, R1 = 16MB */
int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
{
struct tlbe *tlbe = &vcpu->arch.guest_tlb[0];
tlbe->tid = 0;
tlbe->word0 = PPC44x_TLB_16M | PPC44x_TLB_VALID;
tlbe->word1 = 0;
tlbe->word2 = PPC44x_TLB_SX | PPC44x_TLB_SW | PPC44x_TLB_SR;
tlbe++;
tlbe->tid = 0;
tlbe->word0 = 0xef600000 | PPC44x_TLB_4K | PPC44x_TLB_VALID;
tlbe->word1 = 0xef600000;
tlbe->word2 = PPC44x_TLB_SX | PPC44x_TLB_SW | PPC44x_TLB_SR
| PPC44x_TLB_I | PPC44x_TLB_G;
vcpu->arch.pc = 0;
vcpu->arch.msr = 0;
vcpu->arch.gpr[1] = (16<<20) - 8; /* -8 for the callee-save LR slot */
vcpu->arch.shadow_pid = 1;
/* Eye-catching number so we know if the guest takes an interrupt
* before it's programmed its own IVPR. */
vcpu->arch.ivpr = 0x55550000;
/* Since the guest can directly access the timebase, it must know the
* real timebase frequency. Accordingly, it must see the state of
* CCR1[TCS]. */
vcpu->arch.ccr1 = mfspr(SPRN_CCR1);
return 0;
}
int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
{
int i;
regs->pc = vcpu->arch.pc;
regs->cr = vcpu->arch.cr;
regs->ctr = vcpu->arch.ctr;
regs->lr = vcpu->arch.lr;
regs->xer = vcpu->arch.xer;
regs->msr = vcpu->arch.msr;
regs->srr0 = vcpu->arch.srr0;
regs->srr1 = vcpu->arch.srr1;
regs->pid = vcpu->arch.pid;
regs->sprg0 = vcpu->arch.sprg0;
regs->sprg1 = vcpu->arch.sprg1;
regs->sprg2 = vcpu->arch.sprg2;
regs->sprg3 = vcpu->arch.sprg3;
regs->sprg5 = vcpu->arch.sprg4;
regs->sprg6 = vcpu->arch.sprg5;
regs->sprg7 = vcpu->arch.sprg6;
for (i = 0; i < ARRAY_SIZE(regs->gpr); i++)
regs->gpr[i] = vcpu->arch.gpr[i];
return 0;
}
int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
{
int i;
vcpu->arch.pc = regs->pc;
vcpu->arch.cr = regs->cr;
vcpu->arch.ctr = regs->ctr;
vcpu->arch.lr = regs->lr;
vcpu->arch.xer = regs->xer;
vcpu->arch.msr = regs->msr;
vcpu->arch.srr0 = regs->srr0;
vcpu->arch.srr1 = regs->srr1;
vcpu->arch.sprg0 = regs->sprg0;
vcpu->arch.sprg1 = regs->sprg1;
vcpu->arch.sprg2 = regs->sprg2;
vcpu->arch.sprg3 = regs->sprg3;
vcpu->arch.sprg5 = regs->sprg4;
vcpu->arch.sprg6 = regs->sprg5;
vcpu->arch.sprg7 = regs->sprg6;
for (i = 0; i < ARRAY_SIZE(vcpu->arch.gpr); i++)
vcpu->arch.gpr[i] = regs->gpr[i];
return 0;
}
int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
struct kvm_sregs *sregs)
{
return -ENOTSUPP;
}
int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
struct kvm_sregs *sregs)
{
return -ENOTSUPP;
}
int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
return -ENOTSUPP;
}
int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
return -ENOTSUPP;
}
/* 'linear_address' is actually an encoding of AS|PID|EADDR . */
int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
struct kvm_translation *tr)
{
struct tlbe *gtlbe;
int index;
gva_t eaddr;
u8 pid;
u8 as;
eaddr = tr->linear_address;
pid = (tr->linear_address >> 32) & 0xff;
as = (tr->linear_address >> 40) & 0x1;
index = kvmppc_44x_tlb_index(vcpu, eaddr, pid, as);
if (index == -1) {
tr->valid = 0;
return 0;
}
gtlbe = &vcpu->arch.guest_tlb[index];
tr->physical_address = tlb_xlate(gtlbe, eaddr);
/* XXX what does "writeable" and "usermode" even mean? */
tr->valid = 1;
return 0;
}
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