iommu/vt-d: Fixes for v6.14-rc

Hi Joerg,

The following fix has been queued for v6.14-rc:

- Add a missed check in intel_iommu_drain_pasid_prq()

It has been reviewed and tested. Can you please consider it?

Best regards,
baolu

Lu Baolu (1):
iommu/vt-d: Make intel_iommu_drain_pasid_prq() cover faults for RID

 drivers/iommu/intel/prq.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

2.43.0

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.

---
 drivers/iommu/intel/prq.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

index c2d792db52c3..064194399b38 100644
@@ -87,7 +87,9 @@ void intel_iommu_drain_pasid_prq(struct device *dev, u32 pasid)
 		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;
 		}

2.43.0

Applied, thanks Baolu.