Re: [PATCH] perf test record user-regs: Fix mask for vg register

[Leo Yan <leo.yan@linaro.org>]

On Fri, Dec 01, 2023 at 08:46:17PM +0100, vmolnaro@redhat.com wrote:
> From: Veronika Molnarova <vmolnaro@redhat.com>
> 
> The 'vg' register for arm64 shows up in --user_regs as available when
> masking the variable AT_HWCAP with 1 << 22 returns '1' as done in
> perf_regs.c. However, in subtests for support of SVE, the check for
> the 'vg' register is done by masking the variable AT_HWCAP with the value
> 0x200000 which is equals to 1 << 21 instead of 1 << 22. This results in
> inconsistencies on certain systems where the test expects that the 'vg'
> register is not operational when it is, and vice-versa.
> 
> During the testing on a machine that the test expected not to have the
> 'vg' register available, the perf record with option --user-regs showed
> records for the 'vg' register together with all of the others, which
> means that the mask for the subtest of perf_event_attr is off by one.
> Change the value of the mask from 0x200000 to 0x400000 to correct it.
> 
> Signed-off-by: Veronika Molnarova <vmolnaro@redhat.com>

LGTM, except I think it's good to add fix tag:

  Fixes: 9440ebdc333d ("perf test arm64: Add attr tests for new VG register")

With above fix tag:

Reviewed-by: Leo Yan <leo.yan@linaro.org>