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@xxxxxxxxxxxxx>
---
v3:
- these changes compile on book3s, please validate the functionality and
do the necessary adaptations!
- rework patch description
- add common definition for kvmppc_get_last_inst()
- check return values in book3s code
v2:
- integrated kvmppc_get_last_inst() in book3s code and checked build
- addressed cosmetic feedback
arch/powerpc/include/asm/kvm_book3s.h | 28 ++------
arch/powerpc/include/asm/kvm_booke.h | 7 +-
arch/powerpc/include/asm/kvm_ppc.h | 16 +++++
arch/powerpc/kvm/book3s_64_mmu_hv.c | 16 ++---
arch/powerpc/kvm/book3s_paired_singles.c | 38 ++++++----
arch/powerpc/kvm/book3s_pr.c | 116 +++++++++++++++++--------------
arch/powerpc/kvm/booke.c | 3 +
arch/powerpc/kvm/e500_mmu_host.c | 5 ++
arch/powerpc/kvm/emulate.c | 18 +++--
arch/powerpc/kvm/powerpc.c | 10 ++-
10 files changed, 142 insertions(+), 115 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index f52f656..3409572 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -274,30 +274,14 @@ 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)
+static inline int kvmppc_load_last_inst(struct kvm_vcpu *vcpu, bool prev,
+ u32 *inst)
{
- /* 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);
+ ulong pc = kvmppc_get_pc(vcpu);
- 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);
+ if (prev)
+ pc -= 4;
+ return kvmppc_ld(vcpu, &pc, sizeof(u32), &vcpu->arch.last_inst, false);
}
static inline ulong kvmppc_get_fault_dar(struct kvm_vcpu *vcpu)
diff --git a/arch/powerpc/include/asm/kvm_booke.h b/arch/powerpc/include/asm/kvm_booke.h
index c7aed61..1e28371 100644
--- a/arch/powerpc/include/asm/kvm_booke.h
+++ b/arch/powerpc/include/asm/kvm_booke.h
@@ -33,6 +33,8 @@
#define KVMPPC_INST_EHPRIV_DEBUG (KVMPPC_INST_EHPRIV | \
(EHPRIV_OC_DEBUG << EHPRIV_OC_SHIFT))
+extern int kvmppc_load_last_inst(struct kvm_vcpu *vcpu, bool prev, u32 *inst);
+
static inline void kvmppc_set_gpr(struct kvm_vcpu *vcpu, int num, ulong val)
{
vcpu->arch.gpr[num] = val;
@@ -69,11 +71,6 @@ 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;
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 4a7cc45..619be2f 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -234,6 +234,22 @@ 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, bool prev,
+ u32 *inst)
+{
+ int ret = EMULATE_DONE;
+
+ /* 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, prev, &vcpu->arch.last_inst);
+
+ *inst = kvmppc_need_byteswap(vcpu) ? swab32(vcpu->arch.last_inst) :
+ vcpu->arch.last_inst;
+
+ return ret;
+}
+
static inline bool is_kvmppc_hv_enabled(struct kvm *kvm)
{
return kvm->arch.kvm_ops == kvmppc_hv_ops;
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 8056107..2ffb3dd 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -530,21 +530,13 @@ 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, false, &last_inst) != EMULATE_DONE)
+ return RESUME_GUEST;
/*
* WARNING: We do not know for sure whether the instruction we just
@@ -558,7 +550,7 @@ 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;
/*
diff --git a/arch/powerpc/kvm/book3s_paired_singles.c b/arch/powerpc/kvm/book3s_paired_singles.c
index 6c8011f..6362ad4 100644
--- a/arch/powerpc/kvm/book3s_paired_singles.c
+++ b/arch/powerpc/kvm/book3s_paired_singles.c
@@ -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, false, &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;
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 23367a7..48b633c 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -637,42 +637,6 @@ static void kvmppc_giveup_fac(struct kvm_vcpu *vcpu, ulong fac)
#endif
}
-static int kvmppc_read_inst(struct kvm_vcpu *vcpu)
-{
- ulong srr0 = kvmppc_get_pc(vcpu);
- u32 last_inst = kvmppc_get_last_inst(vcpu);
- int ret;
-
- ret = kvmppc_ld(vcpu, &srr0, sizeof(u32), &last_inst, false);
- if (ret == -ENOENT) {
- ulong msr = kvmppc_get_msr(vcpu);
-
- msr = kvmppc_set_field(msr, 33, 33, 1);
- msr = kvmppc_set_field(msr, 34, 36, 0);
- msr = kvmppc_set_field(msr, 42, 47, 0);
- kvmppc_set_msr_fast(vcpu, msr);
- kvmppc_book3s_queue_irqprio(vcpu, BOOK3S_INTERRUPT_INST_STORAGE);
- return EMULATE_AGAIN;
- }
-
- return EMULATE_DONE;
-}
-
-static int kvmppc_check_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr)
-{
-
- /* Need to do paired single emulation? */
- if (!(vcpu->arch.hflags & BOOK3S_HFLAG_PAIRED_SINGLE))
- return EMULATE_DONE;
-
- /* Read out the instruction */
- if (kvmppc_read_inst(vcpu) == EMULATE_DONE)
- /* Need to emulate */
- return EMULATE_FAIL;
-
- return EMULATE_AGAIN;
-}
-
/* Handle external providers (FPU, Altivec, VSX) */
static int kvmppc_handle_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr,
ulong msr)
@@ -977,15 +941,24 @@ 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, false, &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;
@@ -1004,7 +977,7 @@ 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;
@@ -1021,8 +994,25 @@ 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 sets SRR0 to point to the next inst
+ */
+ emul = kvmppc_get_last_inst(vcpu, true, &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);
@@ -1067,36 +1057,53 @@ 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;
+ u32 last_inst;
- switch (exit_nr) {
- case BOOK3S_INTERRUPT_FP_UNAVAIL: ext_msr = MSR_FP; break;
- case BOOK3S_INTERRUPT_ALTIVEC: ext_msr = MSR_VEC; break;
- case BOOK3S_INTERRUPT_VSX: ext_msr = MSR_VSX; break;
- }
+ if (!(vcpu->arch.hflags & BOOK3S_HFLAG_PAIRED_SINGLE)) {
+ /* Do paired single emulation */
+
+ switch (exit_nr) {
+ case BOOK3S_INTERRUPT_FP_UNAVAIL:
+ ext_msr = MSR_FP;
+ break;
+
+ case BOOK3S_INTERRUPT_ALTIVEC:
+ ext_msr = MSR_VEC;
+ break;
+
+ case BOOK3S_INTERRUPT_VSX:
+ ext_msr = MSR_VSX;
+ break;
+ }
- switch (kvmppc_check_ext(vcpu, exit_nr)) {
- case EMULATE_DONE:
- /* everything ok - let's enable the ext */
r = kvmppc_handle_ext(vcpu, exit_nr, ext_msr);
break;
- case EMULATE_FAIL:
+ }
+
+ emul = kvmppc_get_last_inst(vcpu, false, &last_inst);
+ if (emul == EMULATE_DONE) {
/* we need to emulate this instruction */
goto program_interrupt;
break;
- default:
- /* nothing to worry about - go again */
- break;
+ } else {
+ r = RESUME_GUEST;
}
+
break;
}
case BOOK3S_INTERRUPT_ALIGNMENT:
- if (kvmppc_read_inst(vcpu) == EMULATE_DONE) {
- u32 last_inst = kvmppc_get_last_inst(vcpu);
+ {
+ u32 last_inst;
+ int emul = kvmppc_get_last_inst(vcpu, false, &last_inst);
+
+ if (emul == EMULATE_DONE) {
u32 dsisr;
u64 dar;
@@ -1110,6 +1117,7 @@ program_interrupt:
}
r = RESUME_GUEST;
break;
+ }
#ifdef CONFIG_PPC_BOOK3S_64
case BOOK3S_INTERRUPT_FAC_UNAVAIL:
kvmppc_handle_fac(vcpu, vcpu->arch.shadow_fscr >> 56);
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index ab62109..34a42b9 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -752,6 +752,9 @@ 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;
diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
index dd2cc03..f692c12 100644
--- a/arch/powerpc/kvm/e500_mmu_host.c
+++ b/arch/powerpc/kvm/e500_mmu_host.c
@@ -606,6 +606,11 @@ void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 eaddr, gpa_t gpaddr,
}
}
+int kvmppc_load_last_inst(struct kvm_vcpu *vcpu, bool prev, u32 *instr)
+{
+ return EMULATE_FAIL;
+}
+
/************* MMU Notifiers *************/
int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
index da86d9b..c5c64b6 100644
--- a/arch/powerpc/kvm/emulate.c
+++ b/arch/powerpc/kvm/emulate.c
@@ -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
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index bab20f4..1dba84b 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -261,6 +261,9 @@ 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
@@ -270,11 +273,14 @@ 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;
--
1.7.11.7
--
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