selftests: kvm/x86: add test for pmu msr MSR_IA32_PERF_CAPABILITIES

This test will check the effect of various CPUID settings on the
MSR_IA32_PERF_CAPABILITIES MSR, check that whatever user space writes
with KVM_SET_MSR is _not_ modified from the guest and can be retrieved
with KVM_GET_MSR, and check that invalid LBR formats are rejected.

Signed-off-by: Like Xu <like.xu@linux.intel.com>
Message-Id: <20210201051039.255478-12-like.xu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index 95e1a757c629..66926a7f29cc 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -670,6 +670,40 @@ struct kvm_cpuid2 *kvm_get_supported_cpuid(void)
 }
 
 /*
+ * KVM Get MSR
+ *
+ * Input Args:
+ *   msr_index - Index of MSR
+ *
+ * Output Args: None
+ *
+ * Return: On success, value of the MSR. On failure a TEST_ASSERT is produced.
+ *
+ * Get value of MSR for VCPU.
+ */
+uint64_t kvm_get_feature_msr(uint64_t msr_index)
+{
+	struct {
+		struct kvm_msrs header;
+		struct kvm_msr_entry entry;
+	} buffer = {};
+	int r, kvm_fd;
+
+	buffer.header.nmsrs = 1;
+	buffer.entry.index = msr_index;
+	kvm_fd = open(KVM_DEV_PATH, O_RDONLY);
+	if (kvm_fd < 0)
+		exit(KSFT_SKIP);
+
+	r = ioctl(kvm_fd, KVM_GET_MSRS, &buffer.header);
+	TEST_ASSERT(r == 1, "KVM_GET_MSRS IOCTL failed,\n"
+		"  rc: %i errno: %i", r, errno);
+
+	close(kvm_fd);
+	return buffer.entry.data;
+}
+
+/*
  * Locate a cpuid entry.
  *
  * Input Args: