[098/152] x86, vt-d: Handle previous faults after enabling fault handling

From: Greg KH
Date: Wed Jan 05 2011 - 19:42:53 EST

2.6.36-stable review patch. If anyone has any objections, please let us know.


From: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>

commit 7f99d946e71e71d484b7543b49e990508e70d0c0 upstream.

Fault handling is getting enabled after enabling the interrupt-remapping (as
the success of interrupt-remapping can affect the apic mode and hence the
fault handling mode).

Hence there can potentially be some faults between the window of enabling
interrupt-remapping in the vt-d and the fault-handling of the vt-d units.

Handle any previous faults after enabling the vt-d fault handling.

For v2.6.38 cleanup, need to check if we can remove the dmar_fault() in the
enable_intr_remapping() and see if we can enable fault handling along with
enabling intr-remapping.

Signed-off-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
LKML-Reference: <20101201062244.630417138@xxxxxxxxx>
Acked-by: Chris Wright <chrisw@xxxxxxxxxxxx>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

drivers/pci/dmar.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -1414,6 +1414,11 @@ int __init enable_drhd_fault_handling(vo
(unsigned long long)drhd->reg_base_addr, ret);
return -1;
+ /*
+ * Clear any previous faults.
+ */
+ dmar_fault(iommu->irq, iommu);

return 0;

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