iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

KVM: PPC: Allow kvmppc_get_last_inst() to fail

Browse Source 
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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

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;

17
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)
return RESUME_GUEST;
vcpu->arch.last_inst = last_inst;
}
if (kvmppc_get_last_inst(vcpu, INST_GENERIC, &last_inst) !=
EMULATE_DONE)
return RESUME_GUEST;
/*
* 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;