Rework x86's KVM PV features test to align with KVM's new, fixed behavior of not allowing userspace to disable HLT-exiting after vCPUs have been created. Rework the core testcase to disable HLT-exiting before creating a vCPU, and opportunistically modify keep the paired VM+vCPU creation to verify that KVM rejects KVM_CAP_X86_DISABLE_EXITS as expected. Reviewed-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> --- .../selftests/kvm/x86_64/kvm_pv_test.c | 33 +++++++++++++++++-- 1 file changed, 30 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/kvm/x86_64/kvm_pv_test.c b/tools/testing/selftests/kvm/x86_64/kvm_pv_test.c index 2aee93108a54..1b805cbdb47b 100644 --- a/tools/testing/selftests/kvm/x86_64/kvm_pv_test.c +++ b/tools/testing/selftests/kvm/x86_64/kvm_pv_test.c @@ -139,6 +139,7 @@ static void test_pv_unhalt(void) struct kvm_vm *vm; struct kvm_cpuid_entry2 *ent; u32 kvm_sig_old; + int r; if (!(kvm_check_cap(KVM_CAP_X86_DISABLE_EXITS) & KVM_X86_DISABLE_EXITS_HLT)) return; @@ -152,19 +153,45 @@ static void test_pv_unhalt(void) TEST_ASSERT(vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT), "Enabling X86_FEATURE_KVM_PV_UNHALT had no effect"); - /* Make sure KVM clears vcpu->arch.kvm_cpuid */ + /* Verify KVM disallows disabling exits after vCPU creation. */ + r = __vm_enable_cap(vm, KVM_CAP_X86_DISABLE_EXITS, KVM_X86_DISABLE_EXITS_HLT); + TEST_ASSERT(r && errno == EINVAL, + "Disabling exits after vCPU creation didn't fail as expected"); + + kvm_vm_free(vm); + + /* Verify that KVM clear PV_UNHALT from guest CPUID. */ + vm = vm_create(1); + vm_enable_cap(vm, KVM_CAP_X86_DISABLE_EXITS, KVM_X86_DISABLE_EXITS_HLT); + + vcpu = vm_vcpu_add(vm, 0, NULL); + TEST_ASSERT(!vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT), + "vCPU created with PV_UNHALT set by default"); + + vcpu_set_cpuid_feature(vcpu, X86_FEATURE_KVM_PV_UNHALT); + TEST_ASSERT(!vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT), + "PV_UNHALT set in guest CPUID when HLT-exiting is disabled"); + + /* + * Clobber the KVM PV signature and verify KVM does NOT clear PV_UNHALT + * when KVM PV is not present, and DOES clear PV_UNHALT when switching + * back to the correct signature.. + */ ent = vcpu_get_cpuid_entry(vcpu, KVM_CPUID_SIGNATURE); kvm_sig_old = ent->ebx; ent->ebx = 0xdeadbeef; vcpu_set_cpuid(vcpu); - vm_enable_cap(vm, KVM_CAP_X86_DISABLE_EXITS, KVM_X86_DISABLE_EXITS_HLT); + vcpu_set_cpuid_feature(vcpu, X86_FEATURE_KVM_PV_UNHALT); + TEST_ASSERT(vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT), + "PV_UNHALT cleared when using bogus KVM PV signature"); + ent = vcpu_get_cpuid_entry(vcpu, KVM_CPUID_SIGNATURE); ent->ebx = kvm_sig_old; vcpu_set_cpuid(vcpu); TEST_ASSERT(!vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT), - "KVM_FEATURE_PV_UNHALT is set with KVM_CAP_X86_DISABLE_EXITS"); + "PV_UNHALT set in guest CPUID when HLT-exiting is disabled"); /* FIXME: actually test KVM_FEATURE_PV_UNHALT feature */ -- 2.47.0.338.g60cca15819-goog
