From: Sean Christopherson Date: Wed, 26 Feb 2025 23:18:09 +0000 (-0800) Subject: KVM: selftests: Relax assertion on HLT exits if CPU supports Idle HLT X-Git-Tag: v6.15-rc1~195^2~8^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=62838fa5eade1b23d546e81e7aab6d4c92ec12f2;p=thirdparty%2Fkernel%2Flinux.git KVM: selftests: Relax assertion on HLT exits if CPU supports Idle HLT If the CPU supports Idle HLT, which elides HLT VM-Exits if the vCPU has an unmasked pending IRQ or NMI, relax the xAPIC IPI test's assertion on the number of HLT exits to only require that the number of exits is less than or equal to the number of HLT instructions that were executed. I.e. don't fail the test if Idle HLT does what it's supposed to do. Note, unfortunately there's no way to determine if *KVM* supports Idle HLT, as this_cpu_has() checks raw CPU support, and kvm_cpu_has() checks what can be exposed to L1, i.e. the latter would check if KVM supports nested Idle HLT. But, since the assert is purely bonus coverage, checking for CPU support is good enough. Cc: Manali Shukla Tested-by: Manali Shukla Link: https://lore.kernel.org/r/20250226231809.3183093-1-seanjc@google.com Signed-off-by: Sean Christopherson --- diff --git a/tools/testing/selftests/kvm/include/x86/processor.h b/tools/testing/selftests/kvm/include/x86/processor.h index 9d365144ac3ec..a968a56dcb6e7 100644 --- a/tools/testing/selftests/kvm/include/x86/processor.h +++ b/tools/testing/selftests/kvm/include/x86/processor.h @@ -197,6 +197,7 @@ struct kvm_x86_cpu_feature { #define X86_FEATURE_PAUSEFILTER KVM_X86_CPU_FEATURE(0x8000000A, 0, EDX, 10) #define X86_FEATURE_PFTHRESHOLD KVM_X86_CPU_FEATURE(0x8000000A, 0, EDX, 12) #define X86_FEATURE_VGIF KVM_X86_CPU_FEATURE(0x8000000A, 0, EDX, 16) +#define X86_FEATURE_IDLE_HLT KVM_X86_CPU_FEATURE(0x8000000A, 0, EDX, 30) #define X86_FEATURE_SEV KVM_X86_CPU_FEATURE(0x8000001F, 0, EAX, 1) #define X86_FEATURE_SEV_ES KVM_X86_CPU_FEATURE(0x8000001F, 0, EAX, 3) diff --git a/tools/testing/selftests/kvm/x86/xapic_ipi_test.c b/tools/testing/selftests/kvm/x86/xapic_ipi_test.c index 574a944763b79..58d5c132ed8e9 100644 --- a/tools/testing/selftests/kvm/x86/xapic_ipi_test.c +++ b/tools/testing/selftests/kvm/x86/xapic_ipi_test.c @@ -465,7 +465,18 @@ int main(int argc, char *argv[]) cancel_join_vcpu_thread(threads[0], params[0].vcpu); cancel_join_vcpu_thread(threads[1], params[1].vcpu); - TEST_ASSERT_EQ(data->hlt_count, vcpu_get_stat(params[0].vcpu, halt_exits)); + /* + * If the host support Idle HLT, i.e. KVM *might* be using Idle HLT, + * then the number of HLT exits may be less than the number of HLTs + * that were executed, as Idle HLT elides the exit if the vCPU has an + * unmasked, pending IRQ (or NMI). + */ + if (this_cpu_has(X86_FEATURE_IDLE_HLT)) + TEST_ASSERT(data->hlt_count >= vcpu_get_stat(params[0].vcpu, halt_exits), + "HLT insns = %lu, HLT exits = %lu", + data->hlt_count, vcpu_get_stat(params[0].vcpu, halt_exits)); + else + TEST_ASSERT_EQ(data->hlt_count, vcpu_get_stat(params[0].vcpu, halt_exits)); fprintf(stderr, "Test successful after running for %d seconds.\n"