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

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Date:   Wed, 10 May 2017 02:02:46 -0600
From:   "Jan Beulich" <JBeulich@...e.com>
To:     "Juergen Gross" <jgross@...e.com>
Cc:     <xen-devel@...ts.xenproject.org>, <boris.ostrovsky@...cle.com>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [Xen-devel] [PATCH] xen: adjust early dom0 p2m handling to
 xen hypervisor behavior

>>> On 10.05.17 at 06:08, <jgross@...e.com> 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@...e.com>

Reviewed-by: Jan Beulich <jbeulich@...e.com>

Perhaps worth Cc-ing stable@ ?

Jan