On Tue, Dec 27, 2022 at 10:38 AM Aaron Lewis <aaronlewis@xxxxxxxxxx> wrote:
>
> The instructions XGETBV and XSETBV are useful to other tests. Move
> them to processor.h to make them available to be used more broadly.
>
> No functional change intended.
>
> Signed-off-by: Aaron Lewis <aaronlewis@xxxxxxxxxx>
> ---
> .../selftests/kvm/include/x86_64/processor.h | 19 +++++++++++++++
> tools/testing/selftests/kvm/x86_64/amx_test.c | 24 +++----------------
> 2 files changed, 22 insertions(+), 21 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
> index b1a31de7108ac..34957137be375 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/processor.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
> @@ -492,6 +492,25 @@ static inline void set_cr4(uint64_t val)
> __asm__ __volatile__("mov %0, %%cr4" : : "r" (val) : "memory");
> }
>
> +static inline u64 xgetbv(u32 index)
> +{
> + u32 eax, edx;
> +
> + __asm__ __volatile__("xgetbv;"
> + : "=a" (eax), "=d" (edx)
> + : "c" (index));
> + return eax | ((u64)edx << 32);
> +}
> +
> +static inline void xsetbv(u32 index, u64 value)
> +{
> + u32 eax = value;
> + u32 edx = value >> 32;
> +
> + __asm__ __volatile__("xsetbv" :: "a" (eax), "d" (edx), "c" (index));
> +}
> +
> +
Not your change, but shouldn't both of these asm statements have
artificial "memory" clobbers, to prevent reordering?
Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>
