>>> On 25.11.15 at 00:53, <bgr...@netflix.com> wrote:
> --- a/xen/arch/x86/cpu/vpmu_intel.c
> +++ b/xen/arch/x86/cpu/vpmu_intel.c
> @@ -166,10 +166,10 @@ static int core2_get_arch_pmc_count(void)
> */
> static int core2_get_fixed_pmc_count(void)
> {
> - u32 eax;
> + u32 edx;
>
> - eax = cpuid_eax(0xa);
> - return MASK_EXTR(eax, PMU_FIXED_NR_MASK);
> + edx = cpuid_edx(0xa);
> + return MASK_EXTR(edx, PMU_FIXED_NR_MASK);
> }
>
> /* edx bits 5-12: Bit width of fixed-function performance counters */
I'll commit as is since it's an immediate improvement, but I don't think
this is sufficient: The SDM clearly says "if Version ID > 1", which isn't
being tested here or in the immediately following function.
Looking at this I'd also like to note that the triplets
PMU_*_{SHIFT,BITS,MASK} seem to be rather less readable than if
there were just PMU_*_MASK with a simple hex number on the right
side (the SHIFT and BITS ones aren't being used for other than
defining MASK afaics).
Jan
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