Re: [PATCH v5 14/14] iommu/arm-smmu-v3: Report events that belong to devices attached to vIOMMU

[Nicolin Chen <nicolinc@nvidia.com>]

On Thu, Jan 09, 2025 at 07:04:10PM +0800, kernel test robot wrote:
> sparse warnings: (new ones prefixed by >>)
> >> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c:461:21: sparse: sparse: invalid assignment: &=
>    drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c:461:21: sparse:    left side has type restricted __le64
>    drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c:461:21: sparse:    right side has type unsigned long long
>    drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c:462:21: sparse: sparse: invalid assignment: |=
>    drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c:462:21: sparse:    left side has type restricted __le64
>    drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c:462:21: sparse:    right side has type unsigned long long
> >> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c:464:23: sparse: sparse: cast from restricted __le64
>    drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c:465:23: sparse: sparse: cast from restricted __le64

I fixed these with the followings:
-----------------------------------------------------------------------------------
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
index 0c7a5894ba07..aa453e842a39 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
@@ -457,20 +457,28 @@ struct iommufd_viommu *arm_vsmmu_alloc(struct device *dev,
 	return &vsmmu->core;
 }
 
+/* This is basically iommu_vevent_arm_smmuv3 in u64 for conversion */
+struct arm_vsmmu_evt {
+	union {
+		u64 evt[EVTQ_ENT_DWORDS];
+		struct iommu_vevent_arm_smmuv3 uevt;
+	};
+};
+
 int arm_vmaster_report_event(struct arm_smmu_vmaster *vmaster, u64 *evt)
 {
-	struct iommu_vevent_arm_smmuv3 vevt =
-		*(struct iommu_vevent_arm_smmuv3 *)evt;
+	struct arm_vsmmu_evt *vevt = (struct arm_vsmmu_evt *)evt;
+	int i;
 
-	vevt.evt[0] &= ~EVTQ_0_SID;
-	vevt.evt[0] |= FIELD_PREP(EVTQ_0_SID, vmaster->vsid);
+	vevt->evt[0] &= ~EVTQ_0_SID;
+	vevt->evt[0] |= FIELD_PREP(EVTQ_0_SID, vmaster->vsid);
 
-	vevt.evt[0] = cpu_to_le64(vevt.evt[0]);
-	vevt.evt[1] = cpu_to_le64(vevt.evt[1]);
+	for (i = 0; i < EVTQ_ENT_DWORDS; i++)
+		vevt->uevt.evt[i] = cpu_to_le64(vevt->evt[i]);
 
 	return iommufd_viommu_report_event(&vmaster->vsmmu->core,
-					   IOMMU_VEVENTQ_TYPE_ARM_SMMUV3, &vevt,
-					   sizeof(vevt));
+					   IOMMU_VEVENTQ_TYPE_ARM_SMMUV3,
+					   &vevt->uevt, sizeof(vevt->uevt));
 }
 
 MODULE_IMPORT_NS("IOMMUFD");
-----------------------------------------------------------------------------------

This also fixes the array size from 2 to EVTQ_ENT_DWORDS==(4).

@Will,
Would it be possible for you to ack or review the two SMMU patches
in this series? I am still hoping Jason might be able to take this
after I respin a v6.

Thanks!
Nicolin