iommu/vt-d: Make intel_iommu_drain_pasid_prq() cover faults for RID

This driver supports page faults on PCI RID since commit <9f831c16c69e>
("iommu/vt-d: Remove the pasid present check in prq_event_thread") by
allowing the reporting of page faults with the pasid_present field cleared
to the upper layer for further handling. The fundamental assumption here
is that the detach or replace operations act as a fence for page faults.
This implies that all pending page faults associated with a specific RID
or PASID are flushed when a domain is detached or replaced from a device
RID or PASID.

However, the intel_iommu_drain_pasid_prq() helper does not correctly
handle faults for RID. This leads to faults potentially remaining pending
in the iommu hardware queue even after the domain is detached, thereby
violating the aforementioned assumption.

Fix this issue by extending intel_iommu_drain_pasid_prq() to cover faults
for RID.

Fixes: 9f831c16c69e ("iommu/vt-d: Remove the pasid present check in prq_event_thread")
Cc: stable@vger.kernel.org
Suggested-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20250121023150.815972-1-baolu.lu@linux.intel.com
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20250211005512.985563-2-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/intel/prq.c b/drivers/iommu/intel/prq.c
index c2d792db52c3e251a892c33890453228ff623cc7..064194399b38bb74ee11b0519cbdb00bd61f1ec0 100644 (file)
--- a/drivers/iommu/intel/prq.c
+++ b/drivers/iommu/intel/prq.c
@@ -87,7 +87,9 @@ prq_retry:
                struct page_req_dsc *req;
 
                req = &iommu->prq[head / sizeof(*req)];
-               if (!req->pasid_present || req->pasid != pasid) {
+               if (req->rid != sid ||
+                   (req->pasid_present && pasid != req->pasid) ||
+                   (!req->pasid_present && pasid != IOMMU_NO_PASID)) {
                        head = (head + sizeof(*req)) & PRQ_RING_MASK;
                        continue;
                }