Re: [RFC PATCH 08/12] perf/x86: Add APX in extended regs

[Peter Zijlstra]

On Fri, Jun 13, 2025 at 06:49:39AM -0700, kan.liang@xxxxxxxxxxxxxxx wrote:
> From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> 
> Support APX as the extended registers. It can be configured in the
> sample_ext_regs_intr/user.
> 
> Only the PMU with PERF_PMU_CAP_EXTENDED_REGS2 supports the feature.
> The value can be retrieved via the XSAVES.
> 
> Define several macros to simplify the code.
> 
> Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>

Yuck.

How about reclaiming the current horrible XMM register space when the
new sample_simd_reg_words != 0 ?