x86, vt-d: Handle previous faults after enabling fault handling

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@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
LKML-Reference: <20101201062244.630417138@intel.com>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index 0a19708074c2b5265379ec816e777771823ab861..a286959db67e5ee2eef89a9db596c570d81d64dc 100644 (file)
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -1414,6 +1414,11 @@ int __init enable_drhd_fault_handling(void)
                               (unsigned long long)drhd->reg_base_addr, ret);
                        return -1;
                }
+
+               /*
+                * Clear any previous faults.
+                */
+               dmar_fault(iommu->irq, iommu);
        }
 
        return 0;