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

From: Suresh Siddha
Date: Wed Dec 01 2010 - 01:56:16 EST


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>
Cc: stable@xxxxxxxxxx [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;


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