Re: [PATCH v2] selftests: x86: skip the tests if prerequisites aren't fulfilled

["Chang S. Bae" <chang.seok.bae@xxxxxxxxx>]

On 3/14/2024 4:44 AM, Muhammad Usama Anjum wrote:
> Skip instead of failing when prerequisite conditions aren't fulfilled,
> such as invalid xstate values etc. This patch would make the tests show
> as skip when run by:
>    make -C tools/testing/selftests/ TARGETS=x86 run_tests
>
>    ...
>    # timeout set to 45
>    # selftests: x86: amx_64
>    # # xstate cpuid: invalid tile data size/offset: 0/0
>    ok 42 selftests: x86: amx_64 # SKIP
>    # timeout set to 45
>    # selftests: x86: lam_64
>    # # Unsupported LAM feature!
>    ok 43 selftests: x86: lam_64 # SKIP
>    ...
>
> Cc: Chang S. Bae <chang.seok.bae@xxxxxxxxx>
> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Reviewed-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>
> Signed-off-by: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx>
> ---
> Changes since v1:
> - Use arch_prctl to check if amx is supported
> ---
>   tools/testing/selftests/x86/amx.c | 27 ++++++++++-----------------
>   tools/testing/selftests/x86/lam.c |  2 +-
>   2 files changed, 11 insertions(+), 18 deletions(-)
>
> diff --git a/tools/testing/selftests/x86/amx.c b/tools/testing/selftests/x86/amx.c
> index d884fd69dd510..95aad6d8849be 100644
> --- a/tools/testing/selftests/x86/amx.c
> +++ b/tools/testing/selftests/x86/amx.c
> @@ -103,21 +103,6 @@ static void clearhandler(int sig)
>   
>   #define CPUID_LEAF1_ECX_XSAVE_MASK	(1 << 26)
>   #define CPUID_LEAF1_ECX_OSXSAVE_MASK	(1 << 27)
> -static inline void check_cpuid_xsave(void)
> -{
> -	uint32_t eax, ebx, ecx, edx;
> -
> -	/*
> -	 * CPUID.1:ECX.XSAVE[bit 26] enumerates general
> -	 * support for the XSAVE feature set, including
> -	 * XGETBV.
> -	 */
> -	__cpuid_count(1, 0, eax, ebx, ecx, edx);
> -	if (!(ecx & CPUID_LEAF1_ECX_XSAVE_MASK))
> -		fatal_error("cpuid: no CPU xsave support");
> -	if (!(ecx & CPUID_LEAF1_ECX_OSXSAVE_MASK))
> -		fatal_error("cpuid: no OS xsave support");
> -}
>   
>   static uint32_t xbuf_size;
>   
> @@ -350,6 +335,7 @@ enum expected_result { FAIL_EXPECTED, SUCCESS_EXPECTED };
>   
>   /* arch_prctl() and sigaltstack() test */
>   
> +#define ARCH_GET_XCOMP_SUPP	0x1021
>   #define ARCH_GET_XCOMP_PERM	0x1022
>   #define ARCH_REQ_XCOMP_PERM	0x1023
>   
> @@ -928,8 +914,15 @@ static void test_ptrace(void)
>   
>   int main(void)
>   {
> -	/* Check hardware availability at first */
> -	check_cpuid_xsave();
> +	unsigned long features;
> +	long rc;
> +
> +	rc = syscall(SYS_arch_prctl, ARCH_GET_XCOMP_SUPP, &features);
> +	if (rc || (features & XFEATURE_MASK_XTILE) != XFEATURE_MASK_XTILE) {
> +		ksft_print_msg("no AMX support\n");
> +		return KSFT_SKIP;
> +	}
> +

Reviewed-by: Chang S. Bae <chang.seok.bae@xxxxxxxxx>

Thanks,
Chang