Re: [PATCH v3 11/11] iommu/arm-smmu-v3: Add IOMMU_VIOMMU_TYPE_ARM_SMMUV3 support

[Nicolin Chen <nicolinc@nvidia.com>]

On Wed, Oct 09, 2024 at 09:38:11AM -0700, Nicolin Chen wrote:
> Add a new driver-type for ARM SMMUv3 to enum iommu_viommu_type. Implement
> the viommu_alloc op with an arm_vsmmu_alloc function. As an initial step,
> copy the VMID from s2_parent. A later cleanup series is required to move
> the VMID allocation out of the stage-2 domain allocation routine to this.
> 
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   | 18 ++++++++++++++
>  include/uapi/linux/iommufd.h                  |  2 ++
>  .../arm/arm-smmu-v3/arm-smmu-v3-iommufd.c     | 24 +++++++++++++++++++
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   |  1 +
>  4 files changed, 45 insertions(+)

I squashed the following changes to this commit (will be in v4).
It replaces nested_domain->s2_parent with nested_domain->vsmmu:

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 5e235fca8f13..3cd8ad0a8980 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
@@ -36,14 +36,15 @@ arm_smmu_get_msi_mapping_domain(struct iommu_domain *domain)
 	struct arm_smmu_nested_domain *nested_domain =
 		container_of(domain, struct arm_smmu_nested_domain, domain);
 
-	return &nested_domain->s2_parent->domain;
+	return &nested_domain->vsmmu->s2_parent->domain;
 }
 
 static void arm_smmu_make_nested_cd_table_ste(
 	struct arm_smmu_ste *target, struct arm_smmu_master *master,
 	struct arm_smmu_nested_domain *nested_domain, bool ats_enabled)
 {
-	arm_smmu_make_s2_domain_ste(target, master, nested_domain->s2_parent,
+	arm_smmu_make_s2_domain_ste(target, master,
+				    nested_domain->vsmmu->s2_parent,
 				    ats_enabled);
 
 	target->data[0] = cpu_to_le64(STRTAB_STE_0_V |
@@ -84,7 +85,8 @@ static void arm_smmu_make_nested_domain_ste(
 		break;
 	case STRTAB_STE_0_CFG_BYPASS:
 		arm_smmu_make_s2_domain_ste(
-			target, master, nested_domain->s2_parent, ats_enabled);
+			target, master, nested_domain->vsmmu->s2_parent,
+			ats_enabled);
 		break;
 	case STRTAB_STE_0_CFG_ABORT:
 	default:
@@ -109,7 +111,7 @@ static int arm_smmu_attach_dev_nested(struct iommu_domain *domain,
 	struct arm_smmu_ste ste;
 	int ret;
 
-	if (nested_domain->s2_parent->smmu != master->smmu)
+	if (nested_domain->vsmmu->smmu != master->smmu)
 		return -EINVAL;
 	if (arm_smmu_ssids_in_use(&master->cd_table))
 		return -EBUSY;
@@ -164,8 +166,10 @@ static int arm_smmu_validate_vste(struct iommu_hwpt_arm_smmuv3 *arg)
 struct iommu_domain *
 arm_smmu_domain_alloc_nesting(struct device *dev, u32 flags,
 			      struct iommu_domain *parent,
+			      struct iommufd_viommu *viommu,
 			      const struct iommu_user_data *user_data)
 {
+	struct arm_vsmmu *vsmmu = container_of(viommu, struct arm_vsmmu, core);
 	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
 	struct arm_smmu_nested_domain *nested_domain;
 	struct arm_smmu_domain *smmu_parent;
@@ -183,6 +187,10 @@ arm_smmu_domain_alloc_nesting(struct device *dev, u32 flags,
 	    !(master->smmu->features & ARM_SMMU_FEAT_S2FWB))
 		return ERR_PTR(-EOPNOTSUPP);
 
+	/* Driver only supports nesting with the vIOMMU infrastructure */
+	if (!viommu)
+		return ERR_PTR(-EOPNOTSUPP);
+
 	/*
 	 * The core code checks that parent was created with
 	 * IOMMU_HWPT_ALLOC_NEST_PARENT
@@ -206,7 +214,7 @@ arm_smmu_domain_alloc_nesting(struct device *dev, u32 flags,
 
 	nested_domain->domain.type = IOMMU_DOMAIN_NESTED;
 	nested_domain->domain.ops = &arm_smmu_nested_ops;
-	nested_domain->s2_parent = smmu_parent;
+	nested_domain->vsmmu = vsmmu;
 	nested_domain->ste[0] = arg.ste[0];
 	nested_domain->ste[1] = arg.ste[1] & ~cpu_to_le64(STRTAB_STE_1_EATS);
 
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 6a23e6dcd5cf..460d2fe5dd49 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2660,7 +2661,7 @@ to_smmu_domain_devices(struct iommu_domain *domain)
 	    domain->type == IOMMU_DOMAIN_SVA)
 		return to_smmu_domain(domain);
 	if (domain->type == IOMMU_DOMAIN_NESTED)
-		return to_smmu_nested_domain(domain)->s2_parent;
+		return to_smmu_nested_domain(domain)->vsmmu->s2_parent;
 	return NULL;
 }
 
@@ -3128,7 +3129,7 @@ arm_smmu_domain_alloc_user(struct device *dev, u32 flags,
 
 	if (parent)
 		return arm_smmu_domain_alloc_nesting(dev, flags, parent,
-						     user_data);
+						     viommu, user_data);
 
 	if (flags & ~PAGING_FLAGS)
 		return ERR_PTR(-EOPNOTSUPP);
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 844d1dfdea55..0ea1afe1bb7a 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -836,7 +836,7 @@ struct arm_smmu_domain {
 
 struct arm_smmu_nested_domain {
 	struct iommu_domain domain;
-	struct arm_smmu_domain *s2_parent;
+	struct arm_vsmmu *vsmmu;
 
 	__le64 ste[2];
 };
@@ -1018,6 +1018,7 @@ void *arm_smmu_hw_info(struct device *dev, u32 *length, u32 *type);
 struct iommu_domain *
 arm_smmu_domain_alloc_nesting(struct device *dev, u32 flags,
 			      struct iommu_domain *parent,
+			      struct iommufd_viommu *viommu,
 			      const struct iommu_user_data *user_data);
 struct iommufd_viommu *
 arm_vsmmu_alloc(struct iommu_device *iommu_dev, struct iommu_domain *parent,
@@ -1027,6 +1028,7 @@ arm_vsmmu_alloc(struct iommu_device *iommu_dev, struct iommu_domain *parent,
 static inline struct iommu_domain *
 arm_smmu_domain_alloc_nesting(struct device *dev, u32 flags,
 			      struct iommu_domain *parent,
+			      struct iommufd_viommu *viommu,
 			      const struct iommu_user_data *user_data)
 {
 	return ERR_PTR(-EOPNOTSUPP);