Hi Will,

Sorry for the late response.

On Fri, Jul 11, 2025 at 05:14:27PM +0100, Will Deacon wrote:

quoted

 /* MMIO registers */
 #define ARM_SMMU_IDR0			0x0

@@ -720,6 +721,10 @@ struct arm_smmu_impl_ops {
 	int (*init_structures)(struct arm_smmu_device *smmu);
 	struct arm_smmu_cmdq *(*get_secondary_cmdq)(
 		struct arm_smmu_device *smmu, struct arm_smmu_cmdq_ent *ent);
+	const size_t vsmmu_size;
+	const enum iommu_viommu_type vsmmu_type;
+	int (*vsmmu_init)(struct arm_vsmmu *vsmmu,
+			  const struct iommu_user_data *user_data);

It would be nice to avoid adding data members to the ops structure, if

You mean the "vsmmu_size" and "vsmmu_type" right?

So you want them to be removed, by having two impl_ops:
	size_t get_vsmmu_size(enum iommu_viommu_type vsmmu_type);
	int (*vsmmu_init)(struct arm_vsmmu *vsmmu,
			  const struct iommu_user_data *user_data);

right?

at all possible. The easiest thing would probably be to add a function
for getting the vsmmu size and then pushing the two checks against
'vsmmu_type' down into the impl_ops callbacks so that:

  1. If the type is IOMMU_VIOMMU_TYPE_ARM_SMMUV3, we don't bother with
     the impl_ops at all in arm_vsmmu_init() and arm_smmu_get_viommu_size()

Hmm, I was hoping for an implementation could support the default
IOMMU_VIOMMU_TYPE_ARM_SMMUV3 while having its own viommu_ops or so.
But I think your suggestion is fine since there is no such a use
case at this moment :)

  2. Otherwise, we pass the type into the impl_ops and they can check it

Of course, that can be a patch on top of the series as there's no point
respinning the whole just for this.

Thanks for that! I can draft a patch to send later this week once
the requirements are confirmed.

Nicolin