From da8669ff41fa31573375c9a4180f5c080677204b Mon Sep 17 00:00:00 2001 From: Lu Baolu Date: Sat, 23 Apr 2022 16:23:30 +0800 Subject: [PATCH] iommu/vt-d: Drop stop marker messages The page fault handling framework in the IOMMU core explicitly states that it doesn't handle PCI PASID Stop Marker and the IOMMU drivers must discard them before reporting faults. This handles Stop Marker messages in prq_event_thread() before reporting events to the core. The VT-d driver explicitly drains the pending page requests when a CPU page table (represented by a mm struct) is unbound from a PASID according to the procedures defined in the VT-d spec. The Stop Marker messages do not need a response. Hence, it is safe to drop the Stop Marker messages silently if any of them is found in the page request queue. Fixes: d5b9e4bfe0d88 ("iommu/vt-d: Report prq to io-pgfault framework") Signed-off-by: Lu Baolu Reviewed-by: Jacob Pan Reviewed-by: Kevin Tian Link: https://lore.kernel.org/r/20220421113558.3504874-1-baolu.lu@linux.intel.com Link: https://lore.kernel.org/r/20220423082330.3897867-2-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel --- drivers/iommu/intel/svm.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c index 23a3876..7ee37d9 100644 --- a/drivers/iommu/intel/svm.c +++ b/drivers/iommu/intel/svm.c @@ -757,6 +757,10 @@ bad_req: goto bad_req; } + /* Drop Stop Marker message. No need for a response. */ + if (unlikely(req->lpig && !req->rd_req && !req->wr_req)) + goto prq_advance; + if (!svm || svm->pasid != req->pasid) { /* * It can't go away, because the driver is not permitted -- 2.7.4