[patch 4/4] vt-d: handle previous faults after enabling fault handling

[Suresh Siddha <suresh.b.siddha@intel.com>]

[-- Attachment #1: vtd_handle_oldfaults_in_enable_drhd_fault_handling.patch --]
[-- Type: text/plain, Size: 1132 bytes --]

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@intel.com>
Cc: stable@kernel.org [v2.6.32+]
---
 drivers/pci/dmar.c |    5 +++++
 1 file changed, 5 insertions(+)

Index: tip/drivers/pci/dmar.c
===================================================================
--- tip.orig/drivers/pci/dmar.c
+++ tip/drivers/pci/dmar.c
@@ -1417,6 +1417,11 @@ 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;