[PATCH 3/4 v3] KVM: PPC: Alow kvmppc_get_last_inst() to fail
Mihai Caraman
mihai.caraman at freescale.com
Tue Jun 3 01:50:15 EST 2014
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 at freescale.com>
---
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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