1 files changed, 196 insertions, 35 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 c280ba1e6572..4c90f76930f9 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
@@ -14,12 +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 {
 	struct {
 		u64	lbr_format:6;
@@ -36,59 +35,221 @@ union perf_capabilities {
 	u64	capabilities;
 };
 
-static void guest_code(void)
+/*
+ * 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 const union perf_capabilities format_caps = {
+	.lbr_format = -1,
+	.pebs_format = -1,
+};
+
+static void guest_code(uint64_t current_val)
 {
-	wrmsr(MSR_IA32_PERF_CAPABILITIES, PMU_CAP_LBR_FMT);
+	uint8_t vector;
+	int i;
+
+	vector = wrmsr_safe(MSR_IA32_PERF_CAPABILITIES, current_val);
+	GUEST_ASSERT_2(vector == GP_VECTOR, current_val, vector);
+
+	vector = wrmsr_safe(MSR_IA32_PERF_CAPABILITIES, 0);
+	GUEST_ASSERT_2(vector == GP_VECTOR, 0, vector);
+
+	for (i = 0; i < 64; i++) {
+		vector = wrmsr_safe(MSR_IA32_PERF_CAPABILITIES,
+				    current_val ^ BIT_ULL(i));
+		GUEST_ASSERT_2(vector == GP_VECTOR,
+			       current_val ^ BIT_ULL(i), vector);
+	}
+
+	GUEST_DONE();
 }
 
-int main(int argc, char *argv[])
+/*
+ * Verify that guest WRMSRs to PERF_CAPABILITIES #GP regardless of the value
+ * written, that the guest always sees the userspace controlled value, and that
+ * PERF_CAPABILITIES is immutable after KVM_RUN.
+ */
+static void test_guest_wrmsr_perf_capabilities(union perf_capabilities host_cap)
 {
-	struct kvm_vm *vm;
 	struct kvm_vcpu *vcpu;
-	int ret;
-	union perf_capabilities host_cap;
-	uint64_t val;
+	struct kvm_vm *vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+	struct ucall uc;
+	int r, i;
 
-	host_cap.capabilities = kvm_get_feature_msr(MSR_IA32_PERF_CAPABILITIES);
-	host_cap.capabilities &= (PMU_CAP_FW_WRITES | PMU_CAP_LBR_FMT);
+	vm_init_descriptor_tables(vm);
+	vcpu_init_descriptor_tables(vcpu);
 
-	/* Create VM */
-	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+	vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, host_cap.capabilities);
 
-	TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_PDCM));
+	vcpu_args_set(vcpu, 1, host_cap.capabilities);
+	vcpu_run(vcpu);
 
-	TEST_REQUIRE(kvm_cpu_has_p(X86_PROPERTY_PMU_VERSION));
-	TEST_REQUIRE(kvm_cpu_property(X86_PROPERTY_PMU_VERSION) > 0);
+	switch (get_ucall(vcpu, &uc)) {
+	case UCALL_ABORT:
+		REPORT_GUEST_ASSERT_2(uc, "val = 0x%lx, vector = %lu");
+		break;
+	case UCALL_DONE:
+		break;
+	default:
+		TEST_FAIL("Unexpected ucall: %lu", uc.cmd);
+	}
 
-	/* testcase 1, set capabilities when we have PDCM bit */
-	vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, PMU_CAP_FW_WRITES);
+	ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES), host_cap.capabilities);
 
-	/* check capabilities can be retrieved with KVM_GET_MSR */
-	ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES), PMU_CAP_FW_WRITES);
+	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);
+	r = _vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, 0);
+	TEST_ASSERT(!r, "Post-KVM_RUN write '0' didn't fail");
+
+	for (i = 0; i < 64; i++) {
+		r = _vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES,
+				  host_cap.capabilities ^ BIT_ULL(i));
+		TEST_ASSERT(!r, "Post-KVM_RUN write '0x%llx'didn't fail",
+			    host_cap.capabilities ^ BIT_ULL(i));
+	}
+
+	kvm_vm_free(vm);
+}
+
+/*
+ * 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);
 
-	/* testcase 2, check valid LBR formats are accepted */
 	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);
+
+	kvm_vm_free(vm);
+}
 
-	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);
+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, NULL);
+	int bit;
+
+	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);
+
+	kvm_vm_free(vm);
+}
+
+/*
+ * Verify KVM rejects attempts to set unsupported and/or immutable features in
+ * PERF_CAPABILITIES.  Note, LBR format and PEBS format need to be validated
+ * separately as they are multi-bit values, e.g. toggling or setting a single
+ * bit can generate a false positive without dedicated safeguards.
+ */
+static void test_immutable_perf_capabilities(union perf_capabilities host_cap)
+{
+	const uint64_t reserved_caps = (~host_cap.capabilities |
+					immutable_caps.capabilities) &
+				       ~format_caps.capabilities;
+
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm = vm_create_with_one_vcpu(&vcpu, NULL);
+	union perf_capabilities val = host_cap;
+	int r, bit;
+
+	for_each_set_bit(bit, &reserved_caps, 64) {
+		r = _vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES,
+				  host_cap.capabilities ^ BIT_ULL(bit));
+		TEST_ASSERT(!r, "%s immutable feature 0x%llx (bit %d) didn't fail",
+			    host_cap.capabilities & BIT_ULL(bit) ? "Setting" : "Clearing",
+			    BIT_ULL(bit), bit);
+	}
 
 	/*
-	 * Testcase 3, check that an "invalid" LBR format is rejected.  Only an
-	 * exact match of the host's format (and 0/disabled) is allowed.
+	 * KVM only supports the host's native LBR format, as well as '0' (to
+	 * disable LBR support).  Verify KVM rejects all other LBR formats.
 	 */
-	for (val = 1; val <= PMU_CAP_LBR_FMT; val++) {
-		if (val == (host_cap.capabilities & PMU_CAP_LBR_FMT))
+	for (val.lbr_format = 1; val.lbr_format; val.lbr_format++) {
+		if (val.lbr_format == host_cap.lbr_format)
 			continue;
 
-		ret = _vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, val);
-		TEST_ASSERT(!ret, "Bad LBR FMT = 0x%lx didn't fail", val);
+		r = _vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, val.capabilities);
+		TEST_ASSERT(!r, "Bad LBR FMT = 0x%x didn't fail, host = 0x%x",
+			    val.lbr_format, host_cap.lbr_format);
 	}
 
-	printf("Completed perf capability tests.\n");
+	/* Ditto for the PEBS format. */
+	for (val.pebs_format = 1; val.pebs_format; val.pebs_format++) {
+		if (val.pebs_format == host_cap.pebs_format)
+			continue;
+
+		r = _vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, val.capabilities);
+		TEST_ASSERT(!r, "Bad PEBS FMT = 0x%x didn't fail, host = 0x%x",
+			    val.pebs_format, host_cap.pebs_format);
+	}
+
+	kvm_vm_free(vm);
+}
+
+/*
+ * Test that LBR MSRs are writable when LBRs are enabled, and then verify that
+ * disabling the vPMU via CPUID also disables LBR support.  Set bits 2:0 of
+ * LBR_TOS as those bits are writable across all uarch implementations (arch
+ * LBRs will need to poke a different MSR).
+ */
+static void test_lbr_perf_capabilities(union perf_capabilities host_cap)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	int r;
+
+	if (!host_cap.lbr_format)
+		return;
+
+	vm = vm_create_with_one_vcpu(&vcpu, NULL);
+
+	vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, host_cap.capabilities);
+	vcpu_set_msr(vcpu, MSR_LBR_TOS, 7);
+
+	vcpu_clear_cpuid_entry(vcpu, X86_PROPERTY_PMU_VERSION.function);
+
+	r = _vcpu_set_msr(vcpu, MSR_LBR_TOS, 7);
+	TEST_ASSERT(!r, "Writing LBR_TOS should fail after disabling vPMU");
+
 	kvm_vm_free(vm);
 }
+
+int main(int argc, char *argv[])
+{
+	union perf_capabilities host_cap;
+
+	TEST_REQUIRE(get_kvm_param_bool("enable_pmu"));
+	TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_PDCM));
+
+	TEST_REQUIRE(kvm_cpu_has_p(X86_PROPERTY_PMU_VERSION));
+	TEST_REQUIRE(kvm_cpu_property(X86_PROPERTY_PMU_VERSION) > 0);
+
+	host_cap.capabilities = kvm_get_feature_msr(MSR_IA32_PERF_CAPABILITIES);
+
+	TEST_ASSERT(host_cap.full_width_write,
+		    "Full-width writes should always be supported");
+
+	test_basic_perf_capabilities(host_cap);
+	test_fungible_perf_capabilities(host_cap);
+	test_immutable_perf_capabilities(host_cap);
+	test_guest_wrmsr_perf_capabilities(host_cap);
+	test_lbr_perf_capabilities(host_cap);
+}