RFR: 8329031: CPUID feature detection for Advanced Performance Extensions (Intel® APX) [v3]

[Vladimir Kozlov]

On Fri, 7 Jun 2024 02:16:27 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Summary of changes include with the patch:-
>> 
>> 1) CPUID based feature detection check for Intel APX extension (https://www.intel.com/content/www/us/en/developer/articles/technical/advanced-performance-extensions-apx.html)
>> 2) Validation during VM initialization for extended GPRs state save / restoration by OS across context switches of java application threads executing JIT compiled code with new APX ISA.
>> 
>> Kindly review and share your feedback.
>> 
>> Best Regards,
>> Jatin
>
> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Review comments addressed.

src/hotspot/cpu/x86/vm_version_x86.cpp line 443:

> 441: 
> 442:     /* FIXME: Uncomment while integrating JDK-8329032
> 443:     bool save_apx = UseAPX;

What are you missing to uncomment this code?
8329032 is about `.ad` file changes. It should not affect execution of this code. 
You need changes in `register_x86.*` files and may be somewhere else but you don't need C2 changes for this code to work.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18562#discussion_r1630559908