[PATCH v3 09/21] KVM: selftests: Move 0/initial value PERF_CAPS checks to dedicated sub-test

[Sean Christopherson]

Use a separate sub-test to verify userspace can clear PERF_CAPABILITIES
and restore it to the KVM-supported value, as the testcase isn't unique
to the LBR format.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
 .../selftests/kvm/x86_64/vmx_pmu_caps_test.c  | 25 ++++++++++++++-----
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c b/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c
index ac08c0fdd84d..c3b0738e361b 100644
--- a/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c
+++ b/tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c
@@ -41,6 +41,24 @@ static void guest_code(void)
 	wrmsr(MSR_IA32_PERF_CAPABILITIES, PMU_CAP_LBR_FMT);
 }
 
+/*
+ * Verify KVM allows writing PERF_CAPABILITIES with all KVM-supported features
+ * enabled, as well as '0' (to disable all features).
+ */
+static void test_basic_perf_capabilities(union perf_capabilities host_cap)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm = vm_create_with_one_vcpu(&vcpu, NULL);
+
+	vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, 0);
+	ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES), 0);
+
+	vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, host_cap.capabilities);
+	ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES), host_cap.capabilities);
+
+	kvm_vm_free(vm);
+}
+
 static void test_fungible_perf_capabilities(union perf_capabilities host_cap)
 {
 	struct kvm_vcpu *vcpu;
@@ -66,12 +84,6 @@ static void test_immutable_perf_capabilities(union perf_capabilities host_cap)
 	uint64_t val;
 	int ret;
 
-	vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, 0);
-	ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES), 0);
-
-	vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, host_cap.lbr_format);
-	ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES), (u64)host_cap.lbr_format);
-
 	/*
 	 * KVM only supports the host's native LBR format, as well as '0' (to
 	 * disable LBR support).  Verify KVM rejects all other LBR formats.
@@ -98,6 +110,7 @@ int main(int argc, char *argv[])
 	host_cap.capabilities = kvm_get_feature_msr(MSR_IA32_PERF_CAPABILITIES);
 	host_cap.capabilities &= (PMU_CAP_FW_WRITES | PMU_CAP_LBR_FMT);
 
+	test_basic_perf_capabilities(host_cap);
 	test_fungible_perf_capabilities(host_cap);
 	test_immutable_perf_capabilities(host_cap);
 
-- 
2.40.0.rc1.284.g88254d51c5-goog