>>> On 28.02.16 at 13:54, <haozhong.zh...@intel.com> wrote:
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -333,6 +333,23 @@ u64 hvm_get_tsc_scaling_ratio(u32 gtsc_khz)
> return ratio > max_ratio ? 0 : ratio;
> }
>
> +u64 hvm_scale_tsc(const struct domain *d, u64 tsc)
> +{
> + u64 ratio = d->arch.hvm_domain.tsc_scaling_ratio;
> + u64 dummy;
> +
> + if ( ratio == hvm_default_tsc_scaling_ratio )
> + return tsc;
> +
> + /* tsc = (tsc * ratio) >> hvm_funcs.tsc_scaling.ratio_frac_bits */
> + asm ( "mulq %[ratio]; shrdq %[frac],%%rdx,%[tsc]"
> + : [tsc] "+a" (tsc), "=d" (dummy)
Is mixing named and positional asm() operands supported by all
gcc versions we care about? Also strictly speaking "=d" needs
to be switched to "=&d".
Jan
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