iommu: Remove pasid validity check for STALL model page response msg

This is a temp fix to remove the pasid validity checking on page
response msg because, an implementation that supports only STALL
model, but no PRI, page response deosn't need pasid param.
eg. smmuv3 identifies the stalled transaction using StreamID
and STAG(grpid) parameter.

Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>

drivers/iommu/arm-smmu-v3.c

@@ -2551,6 +2551,8 @@ static int arm_smmu_handle_evt(struct arm_smmu_device *smmu, u64 *evt)
 
 		if (ssid_valid)
 			flt->prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
+		if (master->pri_supported)
+			flt->prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PRI_SUPPORT;
 	} else {
 		flt->type = IOMMU_FAULT_DMA_UNRECOV;
 		flt->event = (struct iommu_fault_unrecoverable) {

drivers/iommu/iommu.c

@@ -1196,8 +1196,7 @@ int iommu_page_response(struct device *dev,
 	if (!param || !param->fault_param)
 		return -EINVAL;
 
-	if (msg->version != IOMMU_PAGE_RESP_VERSION_1 ||
-	    msg->flags & ~IOMMU_PAGE_RESP_PASID_VALID)
+	if (msg->version != IOMMU_PAGE_RESP_VERSION_1)
 		return -EINVAL;
 
 	/* Only send response if there is a fault report pending */
@@ -1212,7 +1211,17 @@ int iommu_page_response(struct device *dev,
 	 */
 	list_for_each_entry(evt, &param->fault_param->faults, list) {
 		prm = &evt->fault.prm;
-		pasid_valid = prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
+		pasid_valid = false;
+
+		/*
+		 * For an implementation that supports only STALL model, but
+		 * no PRI, page response doesn't need pasid param. eg. smmuv3
+		 * identifies the stalled transaction using StreamID and
+		 * STAG(grpid) parameter.
+		 */
+		if ((prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID) &&
+		    (prm->flags & IOMMU_FAULT_PAGE_REQUEST_PRI_SUPPORT))
+			pasid_valid = true;
 
 		if ((pasid_valid && prm->pasid != msg->pasid) ||
 		    prm->grpid != msg->grpid)

include/uapi/linux/iommu.h

@@ -92,6 +92,7 @@ struct iommu_fault_page_request {
 #define IOMMU_FAULT_PAGE_REQUEST_PASID_VALID	(1 << 0)
 #define IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE	(1 << 1)
 #define IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA	(1 << 2)
+#define IOMMU_FAULT_PAGE_REQUEST_PRI_SUPPORT	(1 << 3)
 	__u32	flags;
 	__u32	pasid;
 	__u32	grpid;