linux-kernel - Re: [PATCH v2 3/3] selftests/resctrl: Fix non-contiguous CBM check for Hygon

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Message-ID: <86ee2c6d-476e-495d-b36a-6a72a1c98b69@nvidia.com>
Date: Fri, 5 Dec 2025 11:39:06 -0800
From: Fenghua Yu <fenghuay@...dia.com>
To: Xiaochen Shen <shenxiaochen@...n-hieco.net>, tony.luck@...el.com,
 reinette.chatre@...el.com, bp@...en8.de, shuah@...nel.org,
 skhan@...uxfoundation.org
Cc: babu.moger@....com, james.morse@....com, Dave.Martin@....com,
 x86@...nel.org, linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v2 3/3] selftests/resctrl: Fix non-contiguous CBM check
 for Hygon



On 12/5/25 01:25, Xiaochen Shen wrote:
> The resctrl selftest currently fails on Hygon CPUs that always supports
> non-contiguous CBM, printing the error:
> 
>    "# Hardware and kernel differ on non-contiguous CBM support!"
> 
> This occurs because the arch_supports_noncont_cat() function lacks
> vendor detection for Hygon CPUs, preventing proper identification of
> their non-contiguous CBM capability.
> 
> Fix this by adding Hygon vendor ID detection to
> arch_supports_noncont_cat().
> 
> Signed-off-by: Xiaochen Shen <shenxiaochen@...n-hieco.net>
> Reviewed-by: Reinette Chatre <reinette.chatre@...el.com>
> ---
> Maintainer note:
> Even though this is a fix it is not a candidate for backport since it is
> based on another patch series (x86/resctrl: Fix Platform QoS issues for
> Hygon) which is in process of being added to resctrl.
> 
>   tools/testing/selftests/resctrl/cat_test.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c
> index 94cfdba5308d..59a0f80fdc5a 100644
> --- a/tools/testing/selftests/resctrl/cat_test.c
> +++ b/tools/testing/selftests/resctrl/cat_test.c
> @@ -290,8 +290,8 @@ static int cat_run_test(const struct resctrl_test *test, const struct user_param
>   
>   static bool arch_supports_noncont_cat(const struct resctrl_test *test)
>   {
> -	/* AMD always supports non-contiguous CBM. */
> -	if (get_vendor() == ARCH_AMD)
> +	/* AMD and Hygon always supports non-contiguous CBM. */
> +	if (get_vendor() == ARCH_AMD || get_vendor() == ARCH_HYGON)

nit. Better to avoid call get_vendor() twice (or even more in the future)?

unsigned int vendor_id = get_vendor();

if (vendor_id == ARCH_AMD || vendor_id == ARCH_HYGON)


>   		return true;
>   
>   #if defined(__i386__) || defined(__x86_64__) /* arch */
Reviewed-by: Fenghua Yu <fenghuay@...dia.com>

Thanks.

-Fenghua