On 18/08/2025 12:23 pm, Jan Beulich wrote:
> On 15.08.2025 22:41, Andrew Cooper wrote:
>> ... in preparation to be able to use asm goto.
>>
>> Notably this mean that the value parameter must be taken by pointer rather
>> than by value.
>>
>> No functional change.
>>
>> Signed-off-by: Andrew Cooper <[email protected]>
> In principle
> Reviewed-by: Jan Beulich <[email protected]>
Thanks.
> However, having looked at patch 2 first, ...
>
>> @@ -879,14 +879,14 @@ static void intel_init_ppin(const struct cpuinfo_x86
>> *c)
>> case 0x8f: /* Sapphire Rapids X */
>>
>> if ( (c != &boot_cpu_data && !ppin_msr) ||
>> - rdmsr_safe(MSR_PPIN_CTL, val) )
>> + rdmsr_safe(MSR_PPIN_CTL, &val) )
>> return;
> ... with this, wouldn't we be better off using ...
>
>> /* If PPIN is disabled, but not locked, try to enable. */
>> if ( !(val & (PPIN_ENABLE | PPIN_LOCKOUT)) )
>> {
>> wrmsr_safe(MSR_PPIN_CTL, val | PPIN_ENABLE);
>> - rdmsr_safe(MSR_PPIN_CTL, val);
>> + rdmsr_safe(MSR_PPIN_CTL, &val);
> ... plain rdmsr() here, thus not leaving it open to the behavioral change
> patch 2 comes with?
Yeah, probably. At the point we've read it once, and written to it, a
subsequent read is not going fail.
I'll adjust, although it will have to be a rdmsrl().
~Andrew
