x86, dmar: start with sane state while enabling dma and interrupt-remapping

Impact: cleanup/sanitization

Start from a sane state while enabling dma and interrupt-remapping, by
clearing the previous recorded faults and disabling previously
enabled queued invalidation and interrupt-remapping.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/pci/intr_remapping.c b/drivers/pci/intr_remapping.c
index 0d202d73a1ac..a84686b2478b 100644
--- a/drivers/pci/intr_remapping.c
+++ b/drivers/pci/intr_remapping.c
@@ -499,6 +499,23 @@ int __init enable_intr_remapping(int eim)
         struct dmar_drhd_unit *drhd;
         int setup = 0;
 
+        for_each_drhd_unit(drhd) {
+                struct intel_iommu *iommu = drhd->iommu;
+
+                /*
+                 * Clear previous faults.
+                 */
+                dmar_fault(-1, iommu);
+
+                /*
+                 * Disable intr remapping and queued invalidation, if already
+                 * enabled prior to OS handover.
+                 */
+                disable_intr_remapping(iommu);
+
+                dmar_disable_qi(iommu);
+        }
+
         /*
          * check for the Interrupt-remapping support
          */