[PATCH v2 10/14] iommu/arm-smmu-v3: Replace arm_vsmmu_alloc with arm_vsmmu_init

[Nicolin Chen <nicolinc@nvidia.com>]

To ease the for-driver iommufd APIs, get_viommu_size and viommu_init ops
are introduced.

Sanitize the inputs and report the size of struct arm_vsmmu on success, in
arm_smmu_get_viommu_size().

Place the type sanity at the last, becase there will be soon an impl level
get_viommu_size op, which will require the same sanity tests prior. It can
simply insert a piece of code in front of the IOMMU_VIOMMU_TYPE_ARM_SMMUV3
sanity.

The core will ensure the viommu_type is set to the core vIOMMU object, and
pass in the same dev pointer, so arm_vsmmu_init() won't need to repeat the
same sanity tests but to simply init the arm_vsmmu struct.

Remove the arm_vsmmu_alloc, completing the replacement.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   | 11 +++--
 .../arm/arm-smmu-v3/arm-smmu-v3-iommufd.c     | 46 ++++++++++---------
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   |  3 +-
 3 files changed, 32 insertions(+), 28 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 ea41d790463e..bb39af84e6b0 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -1034,18 +1034,19 @@ struct arm_vsmmu {
 
 #if IS_ENABLED(CONFIG_ARM_SMMU_V3_IOMMUFD)
 void *arm_smmu_hw_info(struct device *dev, u32 *length, u32 *type);
-struct iommufd_viommu *arm_vsmmu_alloc(struct device *dev,
-				       struct iommu_domain *parent,
-				       struct iommufd_ctx *ictx,
-				       unsigned int viommu_type);
+size_t arm_smmu_get_viommu_size(struct device *dev,
+				enum iommu_viommu_type viommu_type);
+int arm_vsmmu_init(struct iommufd_viommu *viommu,
+		   struct iommu_domain *parent_domain);
 int arm_smmu_attach_prepare_vmaster(struct arm_smmu_attach_state *state,
 				    struct arm_smmu_nested_domain *nested_domain);
 void arm_smmu_attach_commit_vmaster(struct arm_smmu_attach_state *state);
 void arm_smmu_master_clear_vmaster(struct arm_smmu_master *master);
 int arm_vmaster_report_event(struct arm_smmu_vmaster *vmaster, u64 *evt);
 #else
+#define arm_smmu_get_viommu_size NULL
 #define arm_smmu_hw_info NULL
-#define arm_vsmmu_alloc NULL
+#define arm_vsmmu_init NULL
 
 static inline int
 arm_smmu_attach_prepare_vmaster(struct arm_smmu_attach_state *state,
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 e4fd8d522af8..9f59c95a254c 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
@@ -382,25 +382,14 @@ static const struct iommufd_viommu_ops arm_vsmmu_ops = {
 	.cache_invalidate = arm_vsmmu_cache_invalidate,
 };
 
-struct iommufd_viommu *arm_vsmmu_alloc(struct device *dev,
-				       struct iommu_domain *parent,
-				       struct iommufd_ctx *ictx,
-				       unsigned int viommu_type)
+size_t arm_smmu_get_viommu_size(struct device *dev,
+				enum iommu_viommu_type viommu_type)
 {
-	struct arm_smmu_device *smmu =
-		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_smmu_device *smmu = master->smmu;
 
 	if (!(smmu->features & ARM_SMMU_FEAT_NESTING))
-		return ERR_PTR(-EOPNOTSUPP);
-
-	if (s2_parent->smmu != master->smmu)
-		return ERR_PTR(-EINVAL);
+		return 0;
 
 	/*
 	 * FORCE_SYNC is not set with FEAT_NESTING. Some study of the exact HW
@@ -408,7 +397,7 @@ struct iommufd_viommu *arm_vsmmu_alloc(struct device *dev,
 	 * any change to remove this.
 	 */
 	if (WARN_ON(smmu->options & ARM_SMMU_OPT_CMDQ_FORCE_SYNC))
-		return ERR_PTR(-EOPNOTSUPP);
+		return 0;
 
 	/*
 	 * Must support some way to prevent the VM from bypassing the cache
@@ -420,19 +409,32 @@ struct iommufd_viommu *arm_vsmmu_alloc(struct device *dev,
 	 */
 	if (!arm_smmu_master_canwbs(master) &&
 	    !(smmu->features & ARM_SMMU_FEAT_S2FWB))
-		return ERR_PTR(-EOPNOTSUPP);
+		return 0;
 
-	vsmmu = iommufd_viommu_alloc(ictx, struct arm_vsmmu, core,
-				     &arm_vsmmu_ops);
-	if (IS_ERR(vsmmu))
-		return ERR_CAST(vsmmu);
+	if (viommu_type != IOMMU_VIOMMU_TYPE_ARM_SMMUV3)
+		return 0;
+
+	return VIOMMU_STRUCT_SIZE(struct arm_vsmmu, core);
+}
+
+int arm_vsmmu_init(struct iommufd_viommu *viommu,
+		   struct iommu_domain *parent_domain)
+{
+	struct arm_vsmmu *vsmmu = container_of(viommu, struct arm_vsmmu, core);
+	struct arm_smmu_device *smmu =
+		container_of(viommu->iommu_dev, struct arm_smmu_device, iommu);
+	struct arm_smmu_domain *s2_parent = to_smmu_domain(parent_domain);
+
+	if (s2_parent->smmu != smmu)
+		return -EINVAL;
 
 	vsmmu->smmu = smmu;
 	vsmmu->s2_parent = s2_parent;
 	/* FIXME Move VMID allocation from the S2 domain allocation to here */
 	vsmmu->vmid = s2_parent->s2_cfg.vmid;
 
-	return &vsmmu->core;
+	viommu->ops = &arm_vsmmu_ops;
+	return 0;
 }
 
 int arm_vmaster_report_event(struct arm_smmu_vmaster *vmaster, u64 *evt)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 10cc6dc26b7b..181d07bc1a9d 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -3688,7 +3688,8 @@ static struct iommu_ops arm_smmu_ops = {
 	.get_resv_regions	= arm_smmu_get_resv_regions,
 	.page_response		= arm_smmu_page_response,
 	.def_domain_type	= arm_smmu_def_domain_type,
-	.viommu_alloc		= arm_vsmmu_alloc,
+	.get_viommu_size	= arm_smmu_get_viommu_size,
+	.viommu_init		= arm_vsmmu_init,
 	.user_pasid_table	= 1,
 	.pgsize_bitmap		= -1UL, /* Restricted during device attach */
 	.owner			= THIS_MODULE,
-- 
2.43.0