Remove the IsBranch flag from ENTER and LEAVE in KVM's emulator, as ENTER and LEAVE are stack operations, not branches. Add forced emulation of said instructions to the PMU counters test to prove that KVM diverges from hardware, and to guard against regressions. Fixes: 018d70ffcfec ("KVM: x86: Update vPMCs when retiring branch instructions") Cc: Jim Mattson Signed-off-by: Sean Christopherson --- arch/x86/kvm/emulate.c | 4 ++-- tools/testing/selftests/kvm/x86/pmu_counters_test.c | 8 +++++--- 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 542d3664afa3..23929151a5b8 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -4330,8 +4330,8 @@ static const struct opcode opcode_table[256] = { I(DstReg | SrcMemFAddr | ModRM | No64 | Src2DS, em_lseg), G(ByteOp, group11), G(0, group11), /* 0xC8 - 0xCF */ - I(Stack | SrcImmU16 | Src2ImmByte | IsBranch, em_enter), - I(Stack | IsBranch, em_leave), + I(Stack | SrcImmU16 | Src2ImmByte, em_enter), + I(Stack, em_leave), I(ImplicitOps | SrcImmU16 | IsBranch, em_ret_far_imm), I(ImplicitOps | IsBranch, em_ret_far), D(ImplicitOps | IsBranch), DI(SrcImmByte | IsBranch, intn), diff --git a/tools/testing/selftests/kvm/x86/pmu_counters_test.c b/tools/testing/selftests/kvm/x86/pmu_counters_test.c index 8aaaf25b6111..89c1e462cd1c 100644 --- a/tools/testing/selftests/kvm/x86/pmu_counters_test.c +++ b/tools/testing/selftests/kvm/x86/pmu_counters_test.c @@ -14,10 +14,10 @@ #define NUM_BRANCH_INSNS_RETIRED (NUM_LOOPS) /* - * Number of instructions in each loop. 1 CLFLUSH/CLFLUSHOPT/NOP, 1 MFENCE, - * 1 LOOP. + * Number of instructions in each loop. 1 ENTER, 1 CLFLUSH/CLFLUSHOPT/NOP, + * 1 MFENCE, 1 LEAVE, 1 LOOP. */ -#define NUM_INSNS_PER_LOOP 4 +#define NUM_INSNS_PER_LOOP 6 /* * Number of "extra" instructions that will be counted, i.e. the number of @@ -210,9 +210,11 @@ do { \ __asm__ __volatile__("wrmsr\n\t" \ " mov $" __stringify(NUM_LOOPS) ", %%ecx\n\t" \ "1:\n\t" \ + FEP "enter $0, $0\n\t" \ clflush "\n\t" \ "mfence\n\t" \ "mov %[m], %%eax\n\t" \ + FEP "leave\n\t" \ FEP "loop 1b\n\t" \ FEP "mov %%edi, %%ecx\n\t" \ FEP "xor %%eax, %%eax\n\t" \ base-commit: c8fbf7ceb2ae3f64b0c377c8c21f6df577a13eb4 -- 2.51.0.470.ga7dc726c21-goog