From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Wei Liu <wei.liu2@citrix.com>,
Xen-devel <xen-devel@lists.xenproject.org>
Cc: Ian Jackson <Ian.Jackson@eu.citrix.com>,
Ian Campbell <ian.campbell@citrix.com>
Subject: Re: [PATCH for 4.6 v2 4/5] libxc: don't populate same pfn more than once in populate_pfns
Date: Sun, 6 Sep 2015 17:25:30 +0100 [thread overview]
Message-ID: <55EC68FA.9010503@citrix.com> (raw)
In-Reply-To: <1441411167-32440-5-git-send-email-wei.liu2@citrix.com>
On 05/09/15 00:59, Wei Liu wrote:
> The original implementation of populate_pfns didn't consider the same
> pfn can be present multiple times in the array. The mechanism to prevent
> populating the same pfn multiple times only worked if the recurring pfn
> appeared in different batches.
>
> This bug is discovered by Linux 4.1 32 bit kernel save / restore test,
> which has several ptes pointing to same pfn, which results in an array
> containing recurring pfn. When libxc called x86_pv_localise_page, the
> original implementation would populate the same pfn more than once.
>
> The fix is to set bit in populated bitmap as we generate list of pfns to
> be populated.
>
> Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
next prev parent reply other threads:[~2015-09-06 16:25 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-04 23:59 [PATCH for 4.6 v2 0/5] Migration v2 fix Wei Liu
2015-09-04 23:59 ` [PATCH for 4.6 v2 1/5] libxc: clearer migration v2 debug message Wei Liu
2015-09-04 23:59 ` [PATCH for 4.6 v2 2/5] libxc: migration v2 prefix Memory -> Frames Wei Liu
2015-09-06 16:23 ` Andrew Cooper
2015-09-06 19:21 ` Wei Liu
2015-09-04 23:59 ` [PATCH for 4.6 v2 3/5] libxc: fix indentation Wei Liu
2015-09-04 23:59 ` [PATCH for 4.6 v2 4/5] libxc: don't populate same pfn more than once in populate_pfns Wei Liu
2015-09-06 16:25 ` Andrew Cooper [this message]
2015-09-04 23:59 ` [PATCH for 4.6 v2 5/5] libxc: add assertion to avoid setting same bit more than once Wei Liu
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