On Wed, Dec 11, 2024 at 08:21:42AM +0000, Tian, Kevin wrote:

quoted

From: Nicolin Chen <redacted>
Sent: Wednesday, December 4, 2024 6:10 AM

+
+/**
+ * struct iommu_virq_arm_smmuv3 - ARM SMMUv3 Virtual IRQ
+ *                                (IOMMU_VIRQ_TYPE_ARM_SMMUV3)
+ * @evt: 256-bit ARM SMMUv3 Event record, little-endian.
+ *
+ * StreamID field reports a virtual device ID. To receive a virtual IRQ for a
+ * device, a vDEVICE must be allocated via IOMMU_VDEVICE_ALLOC.
+ */

similar to what's provided for iommu_hw_info_arm_smmuv3, it'd be
good to refer to a section in smmu spec for bit definitions.

Ack.

quoted

 	mutex_lock(&smmu->streams_mutex);
 	master = arm_smmu_find_master(smmu, sid);
 	if (!master) {

@@ -1813,7 +1786,40 @@ static int arm_smmu_handle_evt(struct

arm_smmu_device *smmu, u64 *evt)
 		goto out_unlock;
 	}

-	ret = iommu_report_device_fault(master->dev, &fault_evt);
+	down_read(&master->vmaster_rwsem);

this lock is not required if event is EVTQ_1_STALL?

No. It only protects master->vmaster. Perhaps I can rewrite this
piece to exclude the lock from the EVTQ_1_STALL chunk.

quoted

+	if (evt[1] & EVTQ_1_STALL) {
+		if (evt[1] & EVTQ_1_RnW)
+			perm |= IOMMU_FAULT_PERM_READ;
+		else
+			perm |= IOMMU_FAULT_PERM_WRITE;
+
+		if (evt[1] & EVTQ_1_InD)
+			perm |= IOMMU_FAULT_PERM_EXEC;
+
+		if (evt[1] & EVTQ_1_PnU)
+			perm |= IOMMU_FAULT_PERM_PRIV;
+
+		flt->type = IOMMU_FAULT_PAGE_REQ;
+		flt->prm = (struct iommu_fault_page_request){
+			.flags = IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE,
+			.grpid = FIELD_GET(EVTQ_1_STAG, evt[1]),
+			.perm = perm,
+			.addr = FIELD_GET(EVTQ_2_ADDR, evt[2]),
+		};
+
+		if (ssid_valid) {
+			flt->prm.flags |=
IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
+			flt->prm.pasid = FIELD_GET(EVTQ_0_SSID, evt[0]);
+		}
+
+		ret = iommu_report_device_fault(master->dev, &fault_evt);
+	} else if (master->vmaster && !(evt[1] & EVTQ_1_S2)) {
+		ret = arm_vmaster_report_event(master->vmaster, evt);

Thanks
Nic