Re: [PATCH v2 13/13] iommu/arm-smmu-v3: Report IRQs that belong to devices attached to vIOMMU

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

...

From: Nicolin Chen nicolinc@nvidia.com 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.

...

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.

...

• 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