[PATCH v2 16/21] KVM: selftests: Expand negative testing of guest writes to PERF_CAPABILITIES
From: Sean Christopherson
Date: Thu Feb 09 2023 - 19:33:57 EST
Test that the guest can't write 0 to PERF_CAPABILITIES, can't write the
current value, and can't toggle _any_ bits. There is no reason to special
case the LBR format.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
.../selftests/kvm/x86_64/vmx_pmu_caps_test.c | 61 ++++++++++++++++---
1 file changed, 54 insertions(+), 7 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 d91bf44a2e39..44fc6101a547 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
@@ -54,9 +54,59 @@ static const union perf_capabilities format_caps = {
.pebs_format = -1,
};
-static void guest_code(void)
+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();
+}
+
+/*
+ * 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_vcpu *vcpu;
+ struct kvm_vm *vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+ struct ucall uc;
+
+ vm_init_descriptor_tables(vm);
+ vcpu_init_descriptor_tables(vcpu);
+
+ vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, host_cap.capabilities);
+
+ vcpu_args_set(vcpu, 1, host_cap.capabilities);
+ vcpu_run(vcpu);
+
+ 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);
+ }
+
+ ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES), host_cap.capabilities);
+
+ kvm_vm_free(vm);
}
/*
@@ -79,7 +129,7 @@ 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);
+ struct kvm_vm *vm = vm_create_with_one_vcpu(&vcpu, NULL);
int bit;
for_each_set_bit(bit, &fungible_caps, 64) {
@@ -89,10 +139,6 @@ static void test_fungible_perf_capabilities(union perf_capabilities host_cap)
}
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), host_cap.capabilities);
-
kvm_vm_free(vm);
}
@@ -153,6 +199,7 @@ int main(int argc, char *argv[])
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);
printf("Completed perf capability tests.\n");
}
--
2.39.1.581.gbfd45094c4-goog