From: Like Xu <likexu@xxxxxxxxxxx>
User space only enable guest LBR feature when the exactly supported
LBR format value is initialized to the MSR_IA32_PERF_CAPABILITIES.
The input is also invalid if only partially supported bits are set.
Note for PEBS feature, the PEBS_FORMAT bit field is the primary concern,
thus if the PEBS_FORMAT input is empty, the other bits check about PEBS
(like PEBS_TRAP or ARCH_REG) will be ignored.
Signed-off-by: Like Xu <likexu@xxxxxxxxxxx>
---
tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
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 6ec901dab61e..98483947f921 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
@@ -13,6 +13,7 @@
#define _GNU_SOURCE /* for program_invocation_short_name */
#include <sys/ioctl.h>
+#include <linux/bitmap.h>
#include "kvm_util.h"
#include "vmx.h"
@@ -56,7 +57,7 @@ int main(int argc, char *argv[])
const struct kvm_cpuid_entry2 *entry_a_0;
struct kvm_vm *vm;
struct kvm_vcpu *vcpu;
- int ret;
+ int ret, bit;
union cpuid10_eax eax;
union perf_capabilities host_cap;
@@ -97,6 +98,12 @@ int main(int argc, char *argv[])
ret = _vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, 0x30);
TEST_ASSERT(ret == 0, "Bad PERF_CAPABILITIES didn't fail.");
+ /* testcase 4, reject LBR_FMT if only partially supported bits are set */
+ for_each_set_bit(bit, (unsigned long *)&host_cap.capabilities, 6) {
+ ret = _vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, BIT_ULL(bit));
+ TEST_ASSERT(ret == 0, "Bad PERF_CAPABILITIES didn't fail.");
+ }
+
printf("Completed perf capability tests.\n");
kvm_vm_free(vm);
}
--
2.37.1
