On Tue, May 30, 2023, Jinrong Liang wrote:
> From: Jinrong Liang <cloudliang@xxxxxxxxxxx>
>
> Add test to check if non-existent counters can be accessed in guest after
> determining the number of Intel generic performance counters by CPUID.
> Per SDM, fixed-function performance counter 'i' is supported if ECX[i] ||
> (EDX[4:0] > i). KVM doesn't emulate more counters than it can support.
>
> Co-developed-by: Like Xu <likexu@xxxxxxxxxxx>
> Signed-off-by: Like Xu <likexu@xxxxxxxxxxx>
> Signed-off-by: Jinrong Liang <cloudliang@xxxxxxxxxxx>
> ---
> .../kvm/x86_64/pmu_basic_functionality_test.c | 42 +++++++++++++++++++
> 1 file changed, 42 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/x86_64/pmu_basic_functionality_test.c b/tools/testing/selftests/kvm/x86_64/pmu_basic_functionality_test.c
> index 116437ac2095..e19f8c2774c5 100644
> --- a/tools/testing/selftests/kvm/x86_64/pmu_basic_functionality_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/pmu_basic_functionality_test.c
> @@ -228,10 +228,46 @@ static void test_oob_gp_counter(uint8_t eax_gp_num, uint8_t offset,
> kvm_vm_free(vm);
> }
>
> +static void intel_test_oob_fixed_ctr(uint8_t edx_fix_num,
> + uint32_t fixed_bitmask, uint64_t expected)
> +{
> + struct kvm_vm *vm;
> + struct kvm_vcpu *vcpu;
> + struct kvm_cpuid_entry2 *entry;
> + uint8_t idx = edx_fix_num;
> + bool visible;
> + uint64_t msr_val;
> +
> + vm = pmu_vm_create_with_one_vcpu(&vcpu, guest_wr_and_rd_msrs);
> +
> + entry = vcpu_get_cpuid_entry(vcpu, 0xa);
> + entry->ecx = fixed_bitmask;
> + entry->edx = (entry->edx & ~FIXED_CTR_NUM_MASK) | edx_fix_num;
> + vcpu_set_cpuid(vcpu);
> +
> + /* Per Intel SDM, FxCtr[i]_is_supported := ECX[i] || (EDX[4:0] > i). */
> + visible = (entry->ecx & BIT_ULL(idx) ||
> + ((entry->edx & FIXED_CTR_NUM_MASK) > idx));
Add a helper (in pmu.h) for this one too.
> + /* KVM doesn't emulate more fixed counters than it can support. */
> + if (idx >= X86_INTEL_MAX_FIXED_CTR_NUM)
> + visible = false;
> +
> + vcpu_args_set(vcpu, 4, MSR_CORE_PERF_FIXED_CTR0, 0xffff, idx, 1);
> + if (!visible)
Curly braces need around a multi-line statement.
> + while (run_vcpu(vcpu, &msr_val) != UCALL_DONE)
> + TEST_ASSERT(msr_val == expected,
> + "Unexpected when testing fixed counter num.");
ASSERT_EQ() will print the expected versus actually for you.
