Public bug reported:
SRU Justification:
Impact:
Using SR-IOV with Intel IOMMUs can observe DMAR errors of the
following type:
[606483.223009] DMAR:[fault reason 05] PTE Write access is not set
[606484.071974] dmar: DRHD: handling fault status reg 402
[606484.077121] dmar: DMAR:[DMA Write] Request device [d8:0a.1] fault addr
35c6e000
The DMAR error causes, at a minimum, loss of network traffic
because the request being serviced is lost. Network cards were also
observed to experience transmit timeouts after a DMAR fault.
In this case, these errors arise from a race condition in
the IOTLB management; this race is described (and fixed) in upstream
commit:
commit ea8ea460c9ace60bbb5ac6e5521d637d5c15293d
Author: David Woodhouse <david.woodho...@intel.com>
Date: Wed Mar 5 17:09:32 2014 +0000
iommu/vt-d: Clean up and fix page table clear/free behaviour
This commit first appeared in mainline 3.15. This issue
affects only the Ubuntu 3.13 kernel series.
Fix:
The race avoidance portion of the above was backported to
3.14-stable, but was never incorporated into the Ubuntu 3.13
kernel series.
commit 51d20e1096a711f8cfa9d98a3ac2dd2c7c0fc20c
Author: David Woodhouse <dw...@infradead.org>
Date: Mon Jun 9 14:09:53 2014 +0100
iommu/vt-d: Fix missing IOTLB flush in intel_iommu_unmap()
Based on commit ea8ea460c9ace60bbb5ac6e5521d637d5c15293d upstream
This 3.14-stable patch was tested by the customer and observed
to resolve the issue in their environment.
Testcase:
In this case, the issue occurs on very recent Intel based
servers using two different SR-IOV network cards (i40e and bnxt) at a
customer site. The customer has tested the patch in their environment
and confirmed that it resolves the issue.
** Affects: linux (Ubuntu)
Importance: Undecided
Assignee: Jay Vosburgh (jvosburgh)
Status: New
** Changed in: linux (Ubuntu)
Assignee: (unassigned) => Jay Vosburgh (jvosburgh)
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https://bugs.launchpad.net/bugs/1697053
Title:
Missing IOTLB flush causes DMAR errors with SR-IOV
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