From: Joerg Roedel <joro@8bytes.org>
To: suravee.suthikulpanit@amd.com
Cc: iommu@lists.linux-foundation.org, sherry.hurwitz@amd.com,
kim.naru@amd.com, linux-kernel@vger.kernel.org,
Jay Cornwall <jay.cornwall@amd.com>
Subject: Re: [PATCH] iommu/amd: Fix for L2 race with VM invalidation
Date: Wed, 14 May 2014 11:29:21 +0200 [thread overview]
Message-ID: <20140514092920.GB6026@8bytes.org> (raw)
In-Reply-To: <1400049252-4213-1-git-send-email-suravee.suthikulpanit@amd.com>
On Wed, May 14, 2014 at 01:34:12AM -0500, suravee.suthikulpanit@amd.com wrote:
> A low probability race exists with this fix. Translations received
> within the critical section to PTEs which are concurrently being
> invalidated may resolve to stale mappings.
Sorry, no. This patch can cause silent data corruption when the pages in
these stale mappings get reused. I understand that the current way does
not work either and can cause failures in the GPU, but silent data
corruption is worse than that.
How about putting the page-fault requests on hold between
invalidate_range_start/end()? The GPU will not see the failures, just a
longer delay until the page faults are handled.
Joerg
next prev parent reply other threads:[~2014-05-14 9:29 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-14 6:34 [PATCH] iommu/amd: Fix for L2 race with VM invalidation suravee.suthikulpanit
2014-05-14 9:29 ` Joerg Roedel [this message]
2014-05-14 11:38 ` Cornwall, Jay
2014-05-20 13:32 ` Joerg Roedel
2014-05-20 13:53 ` Cornwall, Jay
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