Re: [Xen-devel] [PATCH] xen: adjust early dom0 p2m handling to xen hypervisor behavior

From: Jan Beulich
Date: Wed May 10 2017 - 04:02:56 EST


>>> On 10.05.17 at 06:08, <jgross@xxxxxxxx> wrote:
> When booted as pv-guest the p2m list presented by the Xen is already
> mapped to virtual addresses. In dom0 case the hypervisor might make use
> of 2M- or 1G-pages for this mapping. Unfortunately while being properly
> aligned in virtual and machine address space, those pages might not be
> aligned properly in guest physical address space.
>
> So when trying to obtain the guest physical address of such a page
> pud_pfn() and pmd_pfn() must be avoided as those will mask away guest
> physical address bits not being zero in this special case.
>
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

Perhaps worth Cc-ing stable@ ?

Jan