On Fri, Jun 24, 2022, Yang Weijiang wrote:
> Add helpers to check whether MSR_CORE_PERF_GLOBAL_CTRL and rdpmc
> are supported in KVM. When pmu is disabled with enable_pmu=0,
> reading MSR_CORE_PERF_GLOBAL_CTRL or executing rdpmc leads to #GP,
> so skip related tests in this case to avoid test failure.
>
> Signed-off-by: Yang Weijiang <weijiang.yang@xxxxxxxxx>
> ---
> lib/x86/processor.h | 10 ++++++++++
> x86/vmx_tests.c | 18 ++++++++++++++++++
> 2 files changed, 28 insertions(+)
>
> diff --git a/lib/x86/processor.h b/lib/x86/processor.h
> index 9a0dad6..70b9193 100644
> --- a/lib/x86/processor.h
> +++ b/lib/x86/processor.h
> @@ -690,4 +690,14 @@ static inline bool cpuid_osxsave(void)
> return cpuid(1).c & (1 << (X86_FEATURE_OSXSAVE % 32));
> }
>
> +static inline u8 pmu_version(void)
> +{
> + return cpuid(10).a & 0xff;
> +}
> +
> +static inline bool has_perf_global_ctrl(void)
Slight preference for this_cpu_has_perf_global_ctrl() or cpu_has_perf_global_ctrl().
> +{
> + return pmu_version() > 1;
> +}
> +
> #endif
> diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
> index 4d581e7..3cf0776 100644
> --- a/x86/vmx_tests.c
> +++ b/x86/vmx_tests.c
> @@ -944,6 +944,14 @@ static void insn_intercept_main(void)
> continue;
> }
>
> + if (insn_table[cur_insn].flag == CPU_RDPMC) {
> + if (!!pmu_version()) {
> + printf("\tFeature required for %s is not supported.\n",
> + insn_table[cur_insn].name);
> + continue;
> + }
> + }
There's no need to copy+paste a bunch of code plus a one-off check, just add
another helper that plays nice with supported_fn().
static inline bool this_cpu_has_pmu(void)
{
return !!pmu_version();
}
> +
> if (insn_table[cur_insn].disabled) {
> printf("\tFeature required for %s is not supported.\n",
> insn_table[cur_insn].name);
> @@ -7490,6 +7498,11 @@ static void test_perf_global_ctrl(u32 nr, const char *name, u32 ctrl_nr,
>
> static void test_load_host_perf_global_ctrl(void)
> {
> + if (!has_perf_global_ctrl()) {
> + report_skip("test_load_host_perf_global_ctrl");
If you're going to print just the function name, then
report_skip(__func__);
will suffice. I'd still prefer a more helpful message, especially since there's
another "skip" in this function.
> + return;
> + }
> +
> if (!(ctrl_exit_rev.clr & EXI_LOAD_PERF)) {
> printf("\"load IA32_PERF_GLOBAL_CTRL\" exit control not supported\n");
> return;
Speaking of said skip, can you clean up the existing code to use report_skip()?
> @@ -7502,6 +7515,11 @@ static void test_load_host_perf_global_ctrl(void)
>
> static void test_load_guest_perf_global_ctrl(void)
> {
> + if (!has_perf_global_ctrl()) {
> + report_skip("test_load_guest_perf_global_ctrl");
> + return;
> + }
> +
> if (!(ctrl_enter_rev.clr & ENT_LOAD_PERF)) {
> printf("\"load IA32_PERF_GLOBAL_CTRL\" entry control not supported\n");
> return;
> --
> 2.27.0
>
