[PATCH v4 17/23] iommu/arm-smmu-v3-iommufd: Add vsmmu_alloc impl op

[Nicolin Chen]

An impl driver might want to allocate its own type of vIOMMU object or the
standard IOMMU_VIOMMU_TYPE_ARM_SMMUV3 by setting up its own SW/HW bits, as
the tegra241-cmdqv driver will add IOMMU_VIOMMU_TYPE_TEGRA241_CMDQV.

Add a vsmmu_alloc op and prioritize it in arm_vsmmu_alloc().

Reviewed-by: Pranjal Shrivastava <praan at google.com>
Signed-off-by: Nicolin Chen <nicolinc at nvidia.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h     |  6 ++++++
 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c | 17 +++++++++++------
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index 6b8f0d20dac3..a5835af72417 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -16,6 +16,7 @@
 #include <linux/sizes.h>
 
 struct arm_smmu_device;
+struct arm_smmu_domain;
 
 /* MMIO registers */
 #define ARM_SMMU_IDR0			0x0
@@ -720,6 +721,11 @@ 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);
+	struct arm_vsmmu *(*vsmmu_alloc)(
+		struct arm_smmu_device *smmu,
+		struct arm_smmu_domain *smmu_domain, struct iommufd_ctx *ictx,
+		unsigned int viommu_type,
+		const struct iommu_user_data *user_data);
 };
 
 /* An SMMUv3 instance */
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 66855cae775e..b316d1df043f 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
@@ -392,10 +392,7 @@ struct iommufd_viommu *arm_vsmmu_alloc(struct device *dev,
 		iommu_get_iommu_dev(dev, struct arm_smmu_device, iommu);
 	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
 	struct arm_smmu_domain *s2_parent = to_smmu_domain(parent);
-	struct arm_vsmmu *vsmmu;
-
-	if (viommu_type != IOMMU_VIOMMU_TYPE_ARM_SMMUV3)
-		return ERR_PTR(-EOPNOTSUPP);
+	struct arm_vsmmu *vsmmu = ERR_PTR(-EOPNOTSUPP);
 
 	if (!(smmu->features & ARM_SMMU_FEAT_NESTING))
 		return ERR_PTR(-EOPNOTSUPP);
@@ -423,8 +420,16 @@ struct iommufd_viommu *arm_vsmmu_alloc(struct device *dev,
 	    !(smmu->features & ARM_SMMU_FEAT_S2FWB))
 		return ERR_PTR(-EOPNOTSUPP);
 
-	vsmmu = iommufd_viommu_alloc(ictx, struct arm_vsmmu, core,
-				     &arm_vsmmu_ops);
+	/* Prioritize the impl that may support IOMMU_VIOMMU_TYPE_ARM_SMMUV3 */
+	if (master->smmu->impl_ops && master->smmu->impl_ops->vsmmu_alloc)
+		vsmmu = master->smmu->impl_ops->vsmmu_alloc(
+			master->smmu, s2_parent, ictx, viommu_type, user_data);
+	if (PTR_ERR(vsmmu) == -EOPNOTSUPP) {
+		/* Otherwise, allocate an IOMMU_VIOMMU_TYPE_ARM_SMMUV3 here */
+		if (viommu_type == IOMMU_VIOMMU_TYPE_ARM_SMMUV3)
+			vsmmu = iommufd_viommu_alloc(ictx, struct arm_vsmmu,
+						     core, &arm_vsmmu_ops);
+	}
 	if (IS_ERR(vsmmu))
 		return ERR_CAST(vsmmu);
 
-- 
2.43.0