[PATCH v14 11/11] selftests: kvm/x86: add test for pmu msr MSR_IA32_PERF_CAPABILITIES

Like Xu
2021-02-01T06:35:50Z

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>
---
tools/testing/selftests/kvm/.gitignore | 1 +
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/x86_64/vmx_pmu_msrs_test.c | 149 ++++++++++++++++++
3 files changed, 151 insertions(+)
create mode 100644 tools/testing/selftests/kvm/x86_64/vmx_pmu_msrs_test.c

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index ce8f4ad39684..28b71efe52a0 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -25,6 +25,7 @@
/x86_64/vmx_set_nested_state_test
/x86_64/vmx_tsc_adjust_test
/x86_64/xss_msr_test
+/x86_64/vmx_pmu_msrs_test
/demand_paging_test
/dirty_log_test
/dirty_log_perf_test
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index fe41c6a0fa67..cf8737828dd4 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -59,6 +59,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/vmx_tsc_adjust_test
TEST_GEN_PROGS_x86_64 += x86_64/xss_msr_test
TEST_GEN_PROGS_x86_64 += x86_64/debug_regs
TEST_GEN_PROGS_x86_64 += x86_64/tsc_msrs_test
+TEST_GEN_PROGS_x86_64 += x86_64/vmx_pmu_msrs_test
TEST_GEN_PROGS_x86_64 += demand_paging_test
TEST_GEN_PROGS_x86_64 += dirty_log_test
TEST_GEN_PROGS_x86_64 += dirty_log_perf_test
diff --git a/tools/testing/selftests/kvm/x86_64/vmx_pmu_msrs_test.c b/tools/testing/selftests/kvm/x86_64/vmx_pmu_msrs_test.c
new file mode 100644
index 000000000000..b3ad63e6ff12
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/vmx_pmu_msrs_test.c
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * VMX-pmu related msrs test
+ *
+ * Copyright (C) 2021 Intel Corporation
+ *
+ * Test to check the effect of various CPUID settings
+ * on the MSR_IA32_PERF_CAPABILITIES MSR, and check that
+ * whatever we write with KVM_SET_MSR is _not_ modified
+ * in the guest and test it can be retrieved with KVM_GET_MSR.
+ *
+ * Test to check that invalid LBR formats are rejected.
+ */
+
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <sys/ioctl.h>
+
+#include "kvm_util.h"
+#include "vmx.h"
+
+#define VCPU_ID 0
+
+#define X86_FEATURE_PDCM (1<<15)
+#define PMU_CAP_FW_WRITES (1ULL << 13)
+#define PMU_CAP_LBR_FMT 0x3f
+
+union cpuid10_eax {
+ struct {
+ unsigned int version_id:8;
+ unsigned int num_counters:8;
+ unsigned int bit_width:8;
+ unsigned int mask_length:8;
+ } split;
+ unsigned int full;
+};
+
+union perf_capabilities {
+ struct {
+ u64 lbr_format:6;
+ u64 pebs_trap:1;
+ u64 pebs_arch_reg:1;
+ u64 pebs_format:4;
+ u64 smm_freeze:1;
+ u64 full_width_write:1;
+ u64 pebs_baseline:1;
+ u64 perf_metrics:1;
+ u64 pebs_output_pt_available:1;
+ u64 anythread_deprecated:1;
+ };
+ u64 capabilities;
+};
+
+uint64_t rdmsr_on_cpu(uint32_t reg)
+{
+ uint64_t data;
+ int fd;
+ char msr_file[64];
+
+ sprintf(msr_file, "/dev/cpu/%d/msr", 0);
+ fd = open(msr_file, O_RDONLY);
+ if (fd < 0)
+ exit(KSFT_SKIP);
+
+ if (pread(fd, &data, sizeof(data), reg) != sizeof(data))
+ exit(KSFT_SKIP);
+
+ close(fd);
+ return data;
+}
+
+static void guest_code(void)
+{
+ wrmsr(MSR_IA32_PERF_CAPABILITIES, PMU_CAP_LBR_FMT);
+}
+
+int main(int argc, char *argv[])
+{
+ struct kvm_cpuid2 *cpuid;
+ struct kvm_cpuid_entry2 *entry_1_0;
+ struct kvm_cpuid_entry2 *entry_a_0;
+ bool pdcm_supported = false;
+ struct kvm_vm *vm;
+ int ret;
+ union cpuid10_eax eax;
+ union perf_capabilities host_cap;
+
+ host_cap.capabilities = rdmsr_on_cpu(MSR_IA32_PERF_CAPABILITIES);
+ host_cap.capabilities &= (PMU_CAP_FW_WRITES | PMU_CAP_LBR_FMT);
+
+ /* Create VM */
+ vm = vm_create_default(VCPU_ID, 0, guest_code);
+ cpuid = kvm_get_supported_cpuid();
+
+ if (kvm_get_cpuid_max_basic() >= 0xa) {
+ entry_1_0 = kvm_get_supported_cpuid_index(1, 0);
+ entry_a_0 = kvm_get_supported_cpuid_index(0xa, 0);
+ pdcm_supported = entry_1_0 && !!(entry_1_0->ecx & X86_FEATURE_PDCM);
+ eax.full = entry_a_0->eax;
+ }
+ if (!pdcm_supported) {
+ print_skip("MSR_IA32_PERF_CAPABILITIES is not supported by the vCPU");
+ exit(KSFT_SKIP);
+ }
+ if (!eax.split.version_id) {
+ print_skip("PMU is not supported by the vCPU");
+ exit(KSFT_SKIP);
+ }
+
+ /* testcase 1, set capabilities when we have PDCM bit */
+ vcpu_set_cpuid(vm, VCPU_ID, cpuid);
+ vcpu_set_msr(vm, 0, MSR_IA32_PERF_CAPABILITIES, PMU_CAP_FW_WRITES);
+
+ /* check capabilities can be retrieved with KVM_GET_MSR */
+ ASSERT_EQ(vcpu_get_msr(vm, VCPU_ID, MSR_IA32_PERF_CAPABILITIES), PMU_CAP_FW_WRITES);
+
+ /* check whatever we write with KVM_SET_MSR is _not_ modified */
+ vcpu_run(vm, VCPU_ID);
+ ASSERT_EQ(vcpu_get_msr(vm, VCPU_ID, MSR_IA32_PERF_CAPABILITIES), PMU_CAP_FW_WRITES);
+
+ /* testcase 2, check valid LBR formats are accepted */
+ vcpu_set_msr(vm, 0, MSR_IA32_PERF_CAPABILITIES, 0);
+ ASSERT_EQ(vcpu_get_msr(vm, VCPU_ID, MSR_IA32_PERF_CAPABILITIES), 0);
+
+ vcpu_set_msr(vm, 0, MSR_IA32_PERF_CAPABILITIES, host_cap.lbr_format);
+ ASSERT_EQ(vcpu_get_msr(vm, VCPU_ID, MSR_IA32_PERF_CAPABILITIES), (u64)host_cap.lbr_format);
+
+ /* testcase 3, check invalid LBR format is rejected */
+ ret = _vcpu_set_msr(vm, 0, MSR_IA32_PERF_CAPABILITIES, PMU_CAP_LBR_FMT);
+ TEST_ASSERT(ret == 0, "Bad PERF_CAPABILITIES didn't fail.");
+
+ /* testcase 4, set capabilities when we don't have PDCM bit */
+ entry_1_0->ecx &= ~X86_FEATURE_PDCM;
+ vcpu_set_cpuid(vm, VCPU_ID, cpuid);
+ ret = _vcpu_set_msr(vm, 0, MSR_IA32_PERF_CAPABILITIES, host_cap.capabilities);
+ TEST_ASSERT(ret == 0, "Bad PERF_CAPABILITIES didn't fail.");
+
+ /* testcase 5, set capabilities when we don't have PMU version bits */
+ entry_1_0->ecx |= X86_FEATURE_PDCM;
+ eax.split.version_id = 0;
+ entry_1_0->ecx = eax.full;
+ vcpu_set_cpuid(vm, VCPU_ID, cpuid);
+ ret = _vcpu_set_msr(vm, 0, MSR_IA32_PERF_CAPABILITIES, PMU_CAP_FW_WRITES);
+ TEST_ASSERT(ret == 0, "Bad PERF_CAPABILITIES didn't fail.");
+
+ vcpu_set_msr(vm, 0, MSR_IA32_PERF_CAPABILITIES, 0);
+ ASSERT_EQ(vcpu_get_msr(vm, VCPU_ID, MSR_IA32_PERF_CAPABILITIES), 0);
+
+ kvm_vm_free(vm);
+}
--
2.29.2