On 26/09/18 08:42, Jan Beulich wrote:
> @@ -1630,6 +1646,66 @@ static void svm_init_erratum_383(const s
> }
> }
>
> +#ifdef CONFIG_PV
> +bool svm_load_segs(unsigned int ldt_ents, unsigned long ldt_base,
> + unsigned int fs_sel, unsigned long fs_base,
> + unsigned int gs_sel, unsigned long gs_base,
> + unsigned long gs_shadow)
> +{
> + unsigned int cpu = smp_processor_id();
> + struct vmcb_struct *vmcb = per_cpu(host_vmcb_va, cpu);
> +
> + if ( unlikely(!vmcb) )
> + return false;
> +
> + if ( !ldt_base )
> + {
> + /*
> + * The actual structure field used here was arbitrarily chosen.
> + * Empirically it doesn't seem to matter much which element is used,
> + * and a clear explanation of the otherwise poor performance has not
> + * been found/provided so far.
> + */
> + asm volatile ( "prefetch %0" :: "m" (vmcb->ldtr) );
prefetchw().
Otherwise, Reviewed-by: Andrew Cooper <[email protected]>
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