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KVM: PPC: Allow kvmppc_get_last_inst() to fail 

On book3e, guest last instruction is read on the exit path using load
external pid (lwepx) dedicated instruction. This load operation may fail
due to TLB eviction and execute-but-not-read entries.

This patch lay down the path for an alternative solution to read the guest
last instruction, by allowing kvmppc_get_lat_inst() function to fail.
Architecture specific implmentations of kvmppc_load_last_inst() may read
last guest instruction and instruct the emulation layer to re-execute the
guest in case of failure.

Make kvmppc_get_last_inst() definition common between architectures.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This commit is contained in:
Mihai Caraman 2014-07-23 19:06:21 +03:00 committed by Alexander Graf
parent 9a26af64d6
commit 51f047261e
11 changed files with 140 additions and 77 deletions
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26
arch/powerpc/include/asm/kvm_book3s.h
View File

@ -276,32 +276,6 @@ static inline bool kvmppc_need_byteswap(struct kvm_vcpu *vcpu)
return (kvmppc_get_msr(vcpu) & MSR_LE) != (MSR_KERNEL & MSR_LE);
}
static inline u32 kvmppc_get_last_inst_internal(struct kvm_vcpu *vcpu, ulong pc)
{
/* Load the instruction manually if it failed to do so in the
* exit path */
if (vcpu->arch.last_inst == KVM_INST_FETCH_FAILED)
kvmppc_ld(vcpu, &pc, sizeof(u32), &vcpu->arch.last_inst, false);
return kvmppc_need_byteswap(vcpu) ? swab32(vcpu->arch.last_inst) :
vcpu->arch.last_inst;
}
static inline u32 kvmppc_get_last_inst(struct kvm_vcpu *vcpu)
{
return kvmppc_get_last_inst_internal(vcpu, kvmppc_get_pc(vcpu));
}
/*
* Like kvmppc_get_last_inst(), but for fetching a sc instruction.
* Because the sc instruction sets SRR0 to point to the following
* instruction, we have to fetch from pc - 4.
*/
static inline u32 kvmppc_get_last_sc(struct kvm_vcpu *vcpu)
{
return kvmppc_get_last_inst_internal(vcpu, kvmppc_get_pc(vcpu) - 4);
}
static inline ulong kvmppc_get_fault_dar(struct kvm_vcpu *vcpu)
{
return vcpu->arch.fault_dar;

5
arch/powerpc/include/asm/kvm_booke.h
View File

@ -69,11 +69,6 @@ static inline bool kvmppc_need_byteswap(struct kvm_vcpu *vcpu)
return false;
}
static inline u32 kvmppc_get_last_inst(struct kvm_vcpu *vcpu)
{
return vcpu->arch.last_inst;
}
static inline void kvmppc_set_ctr(struct kvm_vcpu *vcpu, ulong val)
{
vcpu->arch.ctr = val;

31
arch/powerpc/include/asm/kvm_ppc.h
View File

@ -47,6 +47,11 @@ enum emulation_result {
EMULATE_EXIT_USER, /* emulation requires exit to user-space */
};
enum instruction_type {
INST_GENERIC,
INST_SC, /* system call */
};
extern int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu);
extern int __kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu);
extern void kvmppc_handler_highmem(void);
@ -62,6 +67,9 @@ extern int kvmppc_handle_store(struct kvm_run *run, struct kvm_vcpu *vcpu,
u64 val, unsigned int bytes,
int is_default_endian);
extern int kvmppc_load_last_inst(struct kvm_vcpu *vcpu,
enum instruction_type type, u32 *inst);
extern int kvmppc_emulate_instruction(struct kvm_run *run,
struct kvm_vcpu *vcpu);
extern int kvmppc_emulate_mmio(struct kvm_run *run, struct kvm_vcpu *vcpu);
@ -234,6 +242,29 @@ struct kvmppc_ops {
extern struct kvmppc_ops *kvmppc_hv_ops;
extern struct kvmppc_ops *kvmppc_pr_ops;
static inline int kvmppc_get_last_inst(struct kvm_vcpu *vcpu,
enum instruction_type type, u32 *inst)
{
int ret = EMULATE_DONE;
u32 fetched_inst;
/* Load the instruction manually if it failed to do so in the
* exit path */
if (vcpu->arch.last_inst == KVM_INST_FETCH_FAILED)
ret = kvmppc_load_last_inst(vcpu, type, &vcpu->arch.last_inst);
/* Write fetch_failed unswapped if the fetch failed */
if (ret == EMULATE_DONE)
fetched_inst = kvmppc_need_byteswap(vcpu) ?
swab32(vcpu->arch.last_inst) :
vcpu->arch.last_inst;
else
fetched_inst = vcpu->arch.last_inst;
*inst = fetched_inst;
return ret;
}
static inline bool is_kvmppc_hv_enabled(struct kvm *kvm)
{
return kvm->arch.kvm_ops == kvmppc_hv_ops;

17
arch/powerpc/kvm/book3s.c
View File

@ -488,6 +488,23 @@ mmio:
}
EXPORT_SYMBOL_GPL(kvmppc_ld);
int kvmppc_load_last_inst(struct kvm_vcpu *vcpu, enum instruction_type type,
u32 *inst)
{
ulong pc = kvmppc_get_pc(vcpu);
int r;
if (type == INST_SC)
pc -= 4;
r = kvmppc_ld(vcpu, &pc, sizeof(u32), inst, false);
if (r == EMULATE_DONE)
return r;
else
return EMULATE_AGAIN;
}
EXPORT_SYMBOL_GPL(kvmppc_load_last_inst);
int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
{
return 0;

15
arch/powerpc/kvm/book3s_64_mmu_hv.c
View File

@ -530,21 +530,14 @@ static int instruction_is_store(unsigned int instr)
static int kvmppc_hv_emulate_mmio(struct kvm_run *run, struct kvm_vcpu *vcpu,
unsigned long gpa, gva_t ea, int is_store)
{
int ret;
u32 last_inst;
unsigned long srr0 = kvmppc_get_pc(vcpu);
/* We try to load the last instruction. We don't let
* emulate_instruction do it as it doesn't check what
* kvmppc_ld returns.
/*
* If we fail, we just return to the guest and try executing it again.
*/
if (vcpu->arch.last_inst == KVM_INST_FETCH_FAILED) {
ret = kvmppc_ld(vcpu, &srr0, sizeof(u32), &last_inst, false);
if (ret != EMULATE_DONE || last_inst == KVM_INST_FETCH_FAILED)
if (kvmppc_get_last_inst(vcpu, INST_GENERIC, &last_inst) !=
EMULATE_DONE)
return RESUME_GUEST;
vcpu->arch.last_inst = last_inst;
}
/*
* WARNING: We do not know for sure whether the instruction we just
@ -558,7 +551,7 @@ static int kvmppc_hv_emulate_mmio(struct kvm_run *run, struct kvm_vcpu *vcpu,
* we just return and retry the instruction.
*/
if (instruction_is_store(kvmppc_get_last_inst(vcpu)) != !!is_store)
if (instruction_is_store(last_inst) != !!is_store)
return RESUME_GUEST;
/*

38
arch/powerpc/kvm/book3s_paired_singles.c
View File

@ -639,26 +639,36 @@ static int kvmppc_ps_one_in(struct kvm_vcpu *vcpu, bool rc,
int kvmppc_emulate_paired_single(struct kvm_run *run, struct kvm_vcpu *vcpu)
{
u32 inst = kvmppc_get_last_inst(vcpu);
u32 inst;
enum emulation_result emulated = EMULATE_DONE;
int ax_rd, ax_ra, ax_rb, ax_rc;
short full_d;
u64 *fpr_d, *fpr_a, *fpr_b, *fpr_c;
int ax_rd = inst_get_field(inst, 6, 10);
int ax_ra = inst_get_field(inst, 11, 15);
int ax_rb = inst_get_field(inst, 16, 20);
int ax_rc = inst_get_field(inst, 21, 25);
short full_d = inst_get_field(inst, 16, 31);
u64 *fpr_d = &VCPU_FPR(vcpu, ax_rd);
u64 *fpr_a = &VCPU_FPR(vcpu, ax_ra);
u64 *fpr_b = &VCPU_FPR(vcpu, ax_rb);
u64 *fpr_c = &VCPU_FPR(vcpu, ax_rc);
bool rcomp = (inst & 1) ? true : false;
u32 cr = kvmppc_get_cr(vcpu);
bool rcomp;
u32 cr;
#ifdef DEBUG
int i;
#endif
emulated = kvmppc_get_last_inst(vcpu, INST_GENERIC, &inst);
if (emulated != EMULATE_DONE)
return emulated;
ax_rd = inst_get_field(inst, 6, 10);
ax_ra = inst_get_field(inst, 11, 15);
ax_rb = inst_get_field(inst, 16, 20);
ax_rc = inst_get_field(inst, 21, 25);
full_d = inst_get_field(inst, 16, 31);
fpr_d = &VCPU_FPR(vcpu, ax_rd);
fpr_a = &VCPU_FPR(vcpu, ax_ra);
fpr_b = &VCPU_FPR(vcpu, ax_rb);
fpr_c = &VCPU_FPR(vcpu, ax_rc);
rcomp = (inst & 1) ? true : false;
cr = kvmppc_get_cr(vcpu);
if (!kvmppc_inst_is_paired_single(vcpu, inst))
return EMULATE_FAIL;

45
arch/powerpc/kvm/book3s_pr.c
View File

@ -1018,15 +1018,24 @@ int kvmppc_handle_exit_pr(struct kvm_run *run, struct kvm_vcpu *vcpu,
{
enum emulation_result er;
ulong flags;
u32 last_inst;
int emul;
program_interrupt:
flags = vcpu->arch.shadow_srr1 & 0x1f0000ull;
emul = kvmppc_get_last_inst(vcpu, INST_GENERIC, &last_inst);
if (emul != EMULATE_DONE) {
r = RESUME_GUEST;
break;
}
if (kvmppc_get_msr(vcpu) & MSR_PR) {
#ifdef EXIT_DEBUG
printk(KERN_INFO "Userspace triggered 0x700 exception at 0x%lx (0x%x)\n", kvmppc_get_pc(vcpu), kvmppc_get_last_inst(vcpu));
pr_info("Userspace triggered 0x700 exception at\n 0x%lx (0x%x)\n",
kvmppc_get_pc(vcpu), last_inst);
#endif
if ((kvmppc_get_last_inst(vcpu) & 0xff0007ff) !=
if ((last_inst & 0xff0007ff) !=
(INS_DCBZ & 0xfffffff7)) {
kvmppc_core_queue_program(vcpu, flags);
r = RESUME_GUEST;
@ -1045,7 +1054,7 @@ program_interrupt:
break;
case EMULATE_FAIL:
printk(KERN_CRIT "%s: emulation at %lx failed (%08x)\n",
__func__, kvmppc_get_pc(vcpu), kvmppc_get_last_inst(vcpu));
__func__, kvmppc_get_pc(vcpu), last_inst);
kvmppc_core_queue_program(vcpu, flags);
r = RESUME_GUEST;
break;
@ -1062,8 +1071,23 @@ program_interrupt:
break;
}
case BOOK3S_INTERRUPT_SYSCALL:
{
u32 last_sc;
int emul;
/* Get last sc for papr */
if (vcpu->arch.papr_enabled) {
/* The sc instuction points SRR0 to the next inst */
emul = kvmppc_get_last_inst(vcpu, INST_SC, &last_sc);
if (emul != EMULATE_DONE) {
kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) - 4);
r = RESUME_GUEST;
break;
}
}
if (vcpu->arch.papr_enabled &&
(kvmppc_get_last_sc(vcpu) == 0x44000022) &&
(last_sc == 0x44000022) &&
!(kvmppc_get_msr(vcpu) & MSR_PR)) {
/* SC 1 papr hypercalls */
ulong cmd = kvmppc_get_gpr(vcpu, 3);
@ -1108,21 +1132,19 @@ program_interrupt:
r = RESUME_GUEST;
}
break;
}
case BOOK3S_INTERRUPT_FP_UNAVAIL:
case BOOK3S_INTERRUPT_ALTIVEC:
case BOOK3S_INTERRUPT_VSX:
{
int ext_msr = 0;
int emul;
ulong pc;
u32 last_inst;
if (vcpu->arch.hflags & BOOK3S_HFLAG_PAIRED_SINGLE) {
/* Do paired single instruction emulation */
pc = kvmppc_get_pc(vcpu);
last_inst = kvmppc_get_last_inst(vcpu);
emul = kvmppc_ld(vcpu, &pc, sizeof(u32), &last_inst,
false);
emul = kvmppc_get_last_inst(vcpu, INST_GENERIC,
&last_inst);
if (emul == EMULATE_DONE)
goto program_interrupt;
else
@ -1151,9 +1173,8 @@ program_interrupt:
}
case BOOK3S_INTERRUPT_ALIGNMENT:
{
ulong pc = kvmppc_get_pc(vcpu);
u32 last_inst = kvmppc_get_last_inst(vcpu);
int emul = kvmppc_ld(vcpu, &pc, sizeof(u32), &last_inst, false);
u32 last_inst;
int emul = kvmppc_get_last_inst(vcpu, INST_GENERIC, &last_inst);
if (emul == EMULATE_DONE) {
u32 dsisr;

3
arch/powerpc/kvm/booke.c
View File

@ -702,6 +702,9 @@ static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
* they were actually modified by emulation. */
return RESUME_GUEST_NV;
case EMULATE_AGAIN:
return RESUME_GUEST;
case EMULATE_DO_DCR:
run->exit_reason = KVM_EXIT_DCR;
return RESUME_HOST;

6
arch/powerpc/kvm/e500_mmu_host.c
View File

@ -610,6 +610,12 @@ void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 eaddr, gpa_t gpaddr,
}
}
int kvmppc_load_last_inst(struct kvm_vcpu *vcpu, enum instruction_type type,
u32 *instr)
{
return EMULATE_AGAIN;
}
/************* MMU Notifiers *************/
int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)

18
arch/powerpc/kvm/emulate.c
View File

@ -224,19 +224,25 @@ static int kvmppc_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, int rt)
* 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;
u32 inst;
int ra, rs, rt, sprn;
enum emulation_result emulated;
int advance = 1;
/* this default type might be overwritten by subcategories */
kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);
emulated = kvmppc_get_last_inst(vcpu, false, &inst);
if (emulated != EMULATE_DONE)
return emulated;
pr_debug("Emulating opcode %d / %d\n", get_op(inst), get_xop(inst));
ra = get_ra(inst);
rs = get_rs(inst);
rt = get_rt(inst);
sprn = get_sprn(inst);
switch (get_op(inst)) {
case OP_TRAP:
#ifdef CONFIG_PPC_BOOK3S

11
arch/powerpc/kvm/powerpc.c
View File

@ -280,6 +280,9 @@ int kvmppc_emulate_mmio(struct kvm_run *run, struct kvm_vcpu *vcpu)
* actually modified. */
r = RESUME_GUEST_NV;
break;
case EMULATE_AGAIN:
r = RESUME_GUEST;
break;
case EMULATE_DO_MMIO:
run->exit_reason = KVM_EXIT_MMIO;
/* We must reload nonvolatiles because "update" load/store
@ -289,11 +292,15 @@ int kvmppc_emulate_mmio(struct kvm_run *run, struct kvm_vcpu *vcpu)
r = RESUME_HOST_NV;
break;
case EMULATE_FAIL:
{
u32 last_inst;
kvmppc_get_last_inst(vcpu, false, &last_inst);
/* XXX Deliver Program interrupt to guest. */
printk(KERN_EMERG "%s: emulation failed (%08x)\n", __func__,
kvmppc_get_last_inst(vcpu));
pr_emerg("%s: emulation failed (%08x)\n", __func__, last_inst);
r = RESUME_HOST;
break;
}
default:
WARN_ON(1);
r = RESUME_GUEST;