On 24/01/2024 3:37 pm, Jan Beulich wrote:
> On 23.01.2024 21:59, Andrew Cooper wrote:
>> Always run microcode_update_helper() on the BSP, so the the updated Raw CPU
>> policy doesn't get non-BSP topology details included.
> Wouldn't it be better (and consistent with ...
>
>> Have calculate_raw_cpu_policy() clear the instantanious XSTATE sizes. The
>> value XCR0 | MSR_XSS had when we scanned the policy isn't terribly
>> interesting
>> to report.
> ... this) to purge these details from the raw policy as well then?
I did spend some time considering this.
Rerunning on the same CPU is more resilient to new topology leaves, so
we'd want to be doing that irrespective.
The XCR0/XSS state really is transient, and the useful information is
everywhere else in leaf 0xd.
>
>> When CPUID Masking is active, it affects CPUID instructions issued by Xen
>> too. Transiently disable masking to get a clean scan.
>>
>> Fixes: 694d79ed5aac ("x86/ucode: Refresh raw CPU policy after microcode
>> load")
>> Signed-off-by: Andrew Cooper <[email protected]>
> Irrespective of the question above, I'm also okay with the change as is:
> Reviewed-by: Jan Beulich <[email protected]>
Thanks.
~Andrew
