From: Sean Christopherson Date: Thu, 28 Nov 2024 01:33:44 +0000 (-0800) Subject: KVM: selftests: Update x86's KVM PV test to match KVM's disabling exits behavior X-Git-Tag: v6.14-rc1~94^2~4^2~51 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=59cb3acdb316130c7247a3d3a20d7d6e75e2896a;p=thirdparty%2Flinux.git KVM: selftests: Update x86's KVM PV test to match KVM's disabling exits behavior 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 Reviewed-by: Binbin Wu Reviewed-by: Xiaoyao Li Link: https://lore.kernel.org/r/20241128013424.4096668-18-seanjc@google.com Signed-off-by: Sean Christopherson --- diff --git a/tools/testing/selftests/kvm/x86/kvm_pv_test.c b/tools/testing/selftests/kvm/x86/kvm_pv_test.c index 2aee93108a54c..1b805cbdb47bf 100644 --- a/tools/testing/selftests/kvm/x86/kvm_pv_test.c +++ b/tools/testing/selftests/kvm/x86/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 */