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Re: [Xen-devel] [PATCH REPOST] pv-grub: Fix for incorrect dom->p2m_host[] list initialization
- To: Daniel Kiper <dkiper@xxxxxxxxxxxx>
- From: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>
- Date: Sat, 23 Apr 2011 00:33:32 +0200
- Cc: linux-kernel@xxxxxxxxxxxxxxx, stefano.stabellini@xxxxxxxxxxxxx, xen-devel@xxxxxxxxxxxxxxxxxxx, konrad.wilk@xxxxxxxxxx
- Delivery-date: Fri, 22 Apr 2011 15:35:31 -0700
- List-id: Xen developer discussion <xen-devel.lists.xensource.com>
- Mail-followup-to: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>, Daniel Kiper <dkiper@xxxxxxxxxxxx>, konrad.wilk@xxxxxxxxxx, stefano.stabellini@xxxxxxxxxxxxx, xen-devel@xxxxxxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx
Hello,
Daniel Kiper, le Fri 22 Apr 2011 23:25:45 +0200, a écrit :
> If pfn of newly allocated page is less than currently requested pfn
> then relevant earlier allocated mfn is overwritten which leads to
> domain crash later.
Oops, good catch! And unfortunately it happens seldomly... I guess it
may be the culprit for a fair number of other issues.
> + if (new_pfn < i)
> + for (new_pfn = i; new_pfn < dom->total_pages; ++new_pfn)
> + if (dom->p2m_host[new_pfn] == new_mfn)
> + break;
Instead of looking for the page, which takes a linear time for each page
and thus potentially quadratic time, we should probably rather record
which PFN the MFNs < allocated have been moved to?
Samuel
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