Commit 37f4e79c authored by Sean Christopherson's avatar Sean Christopherson
Browse files

KVM: selftests: Test all fungible features in PERF_CAPABILITIES 

Verify that userspace can set all fungible features in PERF_CAPABILITIES.
Drop the now unused #define of the "full-width writes" flag.

Link: https://lore.kernel.org/r/20230311004618.920745-15-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 69713940

tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c

+24 −5
Original line number Diff line number Diff line
@@ -14,10 +14,11 @@ 
#define _GNU_SOURCE /* for program_invocation_short_name */

#include <sys/ioctl.h>



#include <linux/bitmap.h>



#include "kvm_util.h"

#include "vmx.h"



#define PMU_CAP_FW_WRITES	(1ULL << 13)

#define PMU_CAP_LBR_FMT		0x3f



union perf_capabilities {
@@ -36,6 +37,18 @@ union perf_capabilities { 
	u64	capabilities;

};



/*

 * The LBR format and most PEBS features are immutable, all other features are

 * fungible (if supported by the host and KVM).

 */

static const union perf_capabilities immutable_caps = {

	.lbr_format = -1,

	.pebs_trap  = 1,

	.pebs_arch_reg = 1,

	.pebs_format = -1,

	.pebs_baseline = 1,

};



static void guest_code(void)

{

	wrmsr(MSR_IA32_PERF_CAPABILITIES, PMU_CAP_LBR_FMT);
@@ -58,15 +71,22 @@ static void test_basic_perf_capabilities(union perf_capabilities host_cap) 


static void test_fungible_perf_capabilities(union perf_capabilities host_cap)

{

	const uint64_t fungible_caps = host_cap.capabilities & ~immutable_caps.capabilities;



	struct kvm_vcpu *vcpu;

	struct kvm_vm *vm = vm_create_with_one_vcpu(&vcpu, guest_code);

	int bit;



	/* testcase 1, set capabilities when we have PDCM bit */

	vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, PMU_CAP_FW_WRITES);

	for_each_set_bit(bit, &fungible_caps, 64) {

		vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, BIT_ULL(bit));

		vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES,

			     host_cap.capabilities & ~BIT_ULL(bit));

	}

	vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, host_cap.capabilities);



	/* check whatever we write with KVM_SET_MSR is _not_ modified */

	vcpu_run(vcpu);

	ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES), PMU_CAP_FW_WRITES);

	ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES), host_cap.capabilities);



	kvm_vm_free(vm);

}
@@ -102,7 +122,6 @@ int main(int argc, char *argv[]) 
	TEST_REQUIRE(kvm_cpu_property(X86_PROPERTY_PMU_VERSION) > 0);



	host_cap.capabilities = kvm_get_feature_msr(MSR_IA32_PERF_CAPABILITIES);

	host_cap.capabilities &= (PMU_CAP_FW_WRITES | PMU_CAP_LBR_FMT);



	TEST_ASSERT(host_cap.full_width_write,

		    "Full-width writes should always be supported");