Re: [PATCH v3 2/4] libxc: support of linear p2m list for migration of pv-domains

[Wei Liu <wei.liu2@citrix.com>]

On Wed, Dec 16, 2015 at 10:24:18AM +0100, Juergen Gross wrote:
[...]
> @@ -698,21 +868,19 @@ static int normalise_pagetable(struct xc_sr_context *ctx, const uint64_t *src,
>              /* 32bit guests can only use the first 4 entries of their L3 tables.
>               * All other are potentially used by Xen. */
>              xen_first = 4;
> -            xen_last = 512;
> +            xen_last = 511;

Is this a bug fix in its own right?

Wei.

>              break;
>  
>          case XEN_DOMCTL_PFINFO_L2TAB:
>              /* It is hard to spot Xen mappings in a 32bit guest's L2.  Most
>               * are normal but only a few will have Xen mappings.
> -             *
> -             * 428 = (HYPERVISOR_VIRT_START_PAE >> L2_PAGETABLE_SHIFT_PAE)&0x1ff
> -             *
> -             * ...which is conveniently unavailable to us in a 64bit build.
>               */
> -            if ( pte_to_frame(src[428]) == ctx->x86_pv.compat_m2p_mfn0 )
> +            i = (HYPERVISOR_VIRT_START_X86_32 >> L2_PAGETABLE_SHIFT_PAE) & 511;
> +            if ( pte_to_frame(src[i]) == ctx->x86_pv.compat_m2p_mfn0 )
>              {
> -                xen_first = 428;
> -                xen_last = 512;
> +                xen_first = i;
> +                xen_last = (HYPERVISOR_VIRT_END_X86_32 >>
> +                            L2_PAGETABLE_SHIFT_PAE) & 511;
>              }
>              break;
>          }
> -- 
> 2.6.2
>