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linux/arch/powerpc/kvm/emulate.c
Cédric Le Goater 736017752d KVM: PPC: Book3S: MMIO emulation support for little endian guests 
MMIO emulation reads the last instruction executed by the guest
and then emulates. If the guest is running in Little Endian order,
or more generally in a different endian order of the host, the
instruction needs to be byte-swapped before being emulated.

This patch adds a helper routine which tests the endian order of
the host and the guest in order to decide whether a byteswap is
needed or not. It is then used to byteswap the last instruction
of the guest in the endian order of the host before MMIO emulation
is performed.

Finally, kvmppc_handle_load() of kvmppc_handle_store() are modified
to reverse the endianness of the MMIO if required.

Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
[agraf: add booke handling]
Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-27 16:00:39 +01:00

487 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
* Copyright 2011 Freescale Semiconductor, Inc.
*
* Authors: Hollis Blanchard <hollisb@us.ibm.com>
*/
#include <linux/jiffies.h>
#include <linux/hrtimer.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kvm_host.h>
#include <linux/clockchips.h>
#include <asm/reg.h>
#include <asm/time.h>
#include <asm/byteorder.h>
#include <asm/kvm_ppc.h>
#include <asm/disassemble.h>
#include <asm/ppc-opcode.h>
#include "timing.h"
#include "trace.h"
void kvmppc_emulate_dec(struct kvm_vcpu *vcpu)
{
unsigned long dec_nsec;
unsigned long long dec_time;
pr_debug("mtDEC: %x\n", vcpu->arch.dec);
hrtimer_try_to_cancel(&vcpu->arch.dec_timer);
#ifdef CONFIG_PPC_BOOK3S
/* mtdec lowers the interrupt line when positive. */
kvmppc_core_dequeue_dec(vcpu);
/* POWER4+ triggers a dec interrupt if the value is < 0 */
if (vcpu->arch.dec & 0x80000000) {
kvmppc_core_queue_dec(vcpu);
return;
}
#endif
#ifdef CONFIG_BOOKE
/* On BOOKE, DEC = 0 is as good as decrementer not enabled */
if (vcpu->arch.dec == 0)
return;
#endif
/*
* The decrementer ticks at the same rate as the timebase, so
* that's how we convert the guest DEC value to the number of
* host ticks.
*/
dec_time = vcpu->arch.dec;
/*
* Guest timebase ticks at the same frequency as host decrementer.
* So use the host decrementer calculations for decrementer emulation.
*/
dec_time = dec_time << decrementer_clockevent.shift;
do_div(dec_time, decrementer_clockevent.mult);
dec_nsec = do_div(dec_time, NSEC_PER_SEC);
hrtimer_start(&vcpu->arch.dec_timer,
ktime_set(dec_time, dec_nsec), HRTIMER_MODE_REL);
vcpu->arch.dec_jiffies = get_tb();
}
u32 kvmppc_get_dec(struct kvm_vcpu *vcpu, u64 tb)
{
u64 jd = tb - vcpu->arch.dec_jiffies;
#ifdef CONFIG_BOOKE
if (vcpu->arch.dec < jd)
return 0;
#endif
return vcpu->arch.dec - jd;
}
static int kvmppc_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, int rs)
{
enum emulation_result emulated = EMULATE_DONE;
ulong spr_val = kvmppc_get_gpr(vcpu, rs);
switch (sprn) {
case SPRN_SRR0:
vcpu->arch.shared->srr0 = spr_val;
break;
case SPRN_SRR1:
vcpu->arch.shared->srr1 = spr_val;
break;
/* XXX We need to context-switch the timebase for
* watchdog and FIT. */
case SPRN_TBWL: break;
case SPRN_TBWU: break;
case SPRN_DEC:
vcpu->arch.dec = spr_val;
kvmppc_emulate_dec(vcpu);
break;
case SPRN_SPRG0:
vcpu->arch.shared->sprg0 = spr_val;
break;
case SPRN_SPRG1:
vcpu->arch.shared->sprg1 = spr_val;
break;
case SPRN_SPRG2:
vcpu->arch.shared->sprg2 = spr_val;
break;
case SPRN_SPRG3:
vcpu->arch.shared->sprg3 = spr_val;
break;
/* PIR can legally be written, but we ignore it */
case SPRN_PIR: break;
default:
emulated = vcpu->kvm->arch.kvm_ops->emulate_mtspr(vcpu, sprn,
spr_val);
if (emulated == EMULATE_FAIL)
printk(KERN_INFO "mtspr: unknown spr "
"0x%x\n", sprn);
break;
}
kvmppc_set_exit_type(vcpu, EMULATED_MTSPR_EXITS);
return emulated;
}
static int kvmppc_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, int rt)
{
enum emulation_result emulated = EMULATE_DONE;
ulong spr_val = 0;
switch (sprn) {
case SPRN_SRR0:
spr_val = vcpu->arch.shared->srr0;
break;
case SPRN_SRR1:
spr_val = vcpu->arch.shared->srr1;
break;
case SPRN_PVR:
spr_val = vcpu->arch.pvr;
break;
case SPRN_PIR:
spr_val = vcpu->vcpu_id;
break;
/* Note: mftb and TBRL/TBWL are user-accessible, so
* the guest can always access the real TB anyways.
* In fact, we probably will never see these traps. */
case SPRN_TBWL:
spr_val = get_tb() >> 32;
break;
case SPRN_TBWU:
spr_val = get_tb();
break;
case SPRN_SPRG0:
spr_val = vcpu->arch.shared->sprg0;
break;
case SPRN_SPRG1:
spr_val = vcpu->arch.shared->sprg1;
break;
case SPRN_SPRG2:
spr_val = vcpu->arch.shared->sprg2;
break;
case SPRN_SPRG3:
spr_val = vcpu->arch.shared->sprg3;
break;
/* Note: SPRG4-7 are user-readable, so we don't get
* a trap. */
case SPRN_DEC:
spr_val = kvmppc_get_dec(vcpu, get_tb());
break;
default:
emulated = vcpu->kvm->arch.kvm_ops->emulate_mfspr(vcpu, sprn,
&spr_val);
if (unlikely(emulated == EMULATE_FAIL)) {
printk(KERN_INFO "mfspr: unknown spr "
"0x%x\n", sprn);
}
break;
}
if (emulated == EMULATE_DONE)
kvmppc_set_gpr(vcpu, rt, spr_val);
kvmppc_set_exit_type(vcpu, EMULATED_MFSPR_EXITS);
return emulated;
}
/* XXX to do:
* lhax
* lhaux
* lswx
* lswi
* stswx
* stswi
* lha
* lhau
* lmw
* stmw
*
*/
/* XXX Should probably auto-generate instruction decoding for a particular core
* from opcode tables in the future. */
int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu)
{
u32 inst = kvmppc_get_last_inst(vcpu);
int ra = get_ra(inst);
int rs = get_rs(inst);
int rt = get_rt(inst);
int sprn = get_sprn(inst);
enum emulation_result emulated = EMULATE_DONE;
int advance = 1;
/* this default type might be overwritten by subcategories */
kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);
pr_debug("Emulating opcode %d / %d\n", get_op(inst), get_xop(inst));
switch (get_op(inst)) {
case OP_TRAP:
#ifdef CONFIG_PPC_BOOK3S
case OP_TRAP_64:
kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
#else
kvmppc_core_queue_program(vcpu,
vcpu->arch.shared->esr | ESR_PTR);
#endif
advance = 0;
break;
case 31:
switch (get_xop(inst)) {
case OP_31_XOP_TRAP:
#ifdef CONFIG_64BIT
case OP_31_XOP_TRAP_64:
#endif
#ifdef CONFIG_PPC_BOOK3S
kvmppc_core_queue_program(vcpu, SRR1_PROGTRAP);
#else
kvmppc_core_queue_program(vcpu,
vcpu->arch.shared->esr | ESR_PTR);
#endif
advance = 0;
break;
case OP_31_XOP_LWZX:
emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
break;
case OP_31_XOP_LBZX:
emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
break;
case OP_31_XOP_LBZUX:
emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_31_XOP_STWX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
4, 1);
break;
case OP_31_XOP_STBX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
1, 1);
break;
case OP_31_XOP_STBUX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
1, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_31_XOP_LHAX:
emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
break;
case OP_31_XOP_LHZX:
emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
break;
case OP_31_XOP_LHZUX:
emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_31_XOP_MFSPR:
emulated = kvmppc_emulate_mfspr(vcpu, sprn, rt);
break;
case OP_31_XOP_STHX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
2, 1);
break;
case OP_31_XOP_STHUX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
2, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_31_XOP_MTSPR:
emulated = kvmppc_emulate_mtspr(vcpu, sprn, rs);
break;
case OP_31_XOP_DCBST:
case OP_31_XOP_DCBF:
case OP_31_XOP_DCBI:
/* Do nothing. The guest is performing dcbi because
* hardware DMA is not snooped by the dcache, but
* emulated DMA either goes through the dcache as
* normal writes, or the host kernel has handled dcache
* coherence. */
break;
case OP_31_XOP_LWBRX:
emulated = kvmppc_handle_load(run, vcpu, rt, 4, 0);
break;
case OP_31_XOP_TLBSYNC:
break;
case OP_31_XOP_STWBRX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
4, 0);
break;
case OP_31_XOP_LHBRX:
emulated = kvmppc_handle_load(run, vcpu, rt, 2, 0);
break;
case OP_31_XOP_STHBRX:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
2, 0);
break;
default:
/* Attempt core-specific emulation below. */
emulated = EMULATE_FAIL;
}
break;
case OP_LWZ:
emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
break;
/* TBD: Add support for other 64 bit load variants like ldu, ldux, ldx etc. */
case OP_LD:
rt = get_rt(inst);
emulated = kvmppc_handle_load(run, vcpu, rt, 8, 1);
break;
case OP_LWZU:
emulated = kvmppc_handle_load(run, vcpu, rt, 4, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_LBZ:
emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
break;
case OP_LBZU:
emulated = kvmppc_handle_load(run, vcpu, rt, 1, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_STW:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
4, 1);
break;
/* TBD: Add support for other 64 bit store variants like stdu, stdux, stdx etc. */
case OP_STD:
rs = get_rs(inst);
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
8, 1);
break;
case OP_STWU:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
4, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_STB:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
1, 1);
break;
case OP_STBU:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
1, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_LHZ:
emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
break;
case OP_LHZU:
emulated = kvmppc_handle_load(run, vcpu, rt, 2, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_LHA:
emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
break;
case OP_LHAU:
emulated = kvmppc_handle_loads(run, vcpu, rt, 2, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
case OP_STH:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
2, 1);
break;
case OP_STHU:
emulated = kvmppc_handle_store(run, vcpu,
kvmppc_get_gpr(vcpu, rs),
2, 1);
kvmppc_set_gpr(vcpu, ra, vcpu->arch.vaddr_accessed);
break;
default:
emulated = EMULATE_FAIL;
}
if (emulated == EMULATE_FAIL) {
emulated = vcpu->kvm->arch.kvm_ops->emulate_op(run, vcpu, inst,
&advance);
if (emulated == EMULATE_AGAIN) {
advance = 0;
} else if (emulated == EMULATE_FAIL) {
advance = 0;
printk(KERN_ERR "Couldn't emulate instruction 0x%08x "
"(op %d xop %d)\n", inst, get_op(inst), get_xop(inst));
kvmppc_core_queue_program(vcpu, 0);
}
}
trace_kvm_ppc_instr(inst, kvmppc_get_pc(vcpu), emulated);
/* Advance past emulated instruction. */
if (advance)
kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
return emulated;
}
EXPORT_SYMBOL_GPL(kvmppc_emulate_instruction);
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