From baa36dac6ca8ecd709dafb87a79d3bead40e48fe Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 10 Mar 2023 16:46:13 -0800 Subject: [PATCH] KVM: selftests: Expand negative testing of guest writes to PERF_CAPABILITIES 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. Link: https://lore.kernel.org/r/20230311004618.920745-17-seanjc@google.com Signed-off-by: Sean Christopherson --- .../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"); } -- 2.11.0