On Fri, 2024-05-17 at 10:38 -0700, Sean Christopherson wrote: > 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. > > 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 */ > Reviewed-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx> Best regards, Maxim Levitsky
