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From:   Nicolin Chen <nicolinc@nvidia.com>
To:     <jgg@nvidia.com>, <robin.murphy@arm.com>, <will@kernel.org>
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        <linux-kernel@vger.kernel.org>
Subject: [PATCH v1 11/14] iommu/arm-smmu-v3: Add arm_smmu_domain_alloc_user
Date:   Thu, 9 Mar 2023 02:53:47 -0800
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The arm_smmu_domain_alloc_user callback function is used for userspace to
allocate iommu_domains, such as standalone stage-1 domain, nested stage-1
domain, and nested stage-2 domain. The input user_data is in the type of
struct iommu_hwpt_arm_smmuv3 that contains the configurations of a nested
stage-1 or a nested stage-2 iommu_domain. A NULL user_data will just opt
in a standalone stage-1 domain allocation.

Add a constitutive function __arm_smmu_domain_alloc to support that.

Since ops->domain_alloc_user has a valid dev pointer, the master pointer
is available when calling __arm_smmu_domain_alloc() in this case, meaning
that arm_smmu_domain_finalise() can be done at the allocation stage. This
allows IOMMUFD to initialize the hw_pagetable for the domain.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 95 ++++++++++++++-------
 1 file changed, 65 insertions(+), 30 deletions(-)

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 2d29f7320570..5ff74edfbd68 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2053,36 +2053,6 @@ static void *arm_smmu_hw_info(struct device *dev, u32 *length)
 	return info;
 }
 
-static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
-{
-	struct arm_smmu_domain *smmu_domain;
-
-	if (type == IOMMU_DOMAIN_SVA)
-		return arm_smmu_sva_domain_alloc();
-
-	if (type != IOMMU_DOMAIN_UNMANAGED &&
-	    type != IOMMU_DOMAIN_DMA &&
-	    type != IOMMU_DOMAIN_DMA_FQ &&
-	    type != IOMMU_DOMAIN_IDENTITY)
-		return NULL;
-
-	/*
-	 * Allocate the domain and initialise some of its data structures.
-	 * We can't really do anything meaningful until we've added a
-	 * master.
-	 */
-	smmu_domain = kzalloc(sizeof(*smmu_domain), GFP_KERNEL);
-	if (!smmu_domain)
-		return NULL;
-
-	mutex_init(&smmu_domain->init_mutex);
-	INIT_LIST_HEAD(&smmu_domain->devices);
-	spin_lock_init(&smmu_domain->devices_lock);
-	INIT_LIST_HEAD(&smmu_domain->mmu_notifiers);
-
-	return &smmu_domain->domain;
-}
-
 static struct iommu_domain *arm_smmu_get_unmanaged_domain(struct device *dev)
 {
 	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
@@ -2893,10 +2863,75 @@ static void arm_smmu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
 	arm_smmu_sva_remove_dev_pasid(domain, dev, pasid);
 }
 
+static struct iommu_domain *
+__arm_smmu_domain_alloc(unsigned type,
+			struct arm_smmu_domain *s2,
+			struct arm_smmu_master *master,
+			const struct iommu_hwpt_arm_smmuv3 *user_cfg)
+{
+	struct arm_smmu_domain *smmu_domain;
+	struct iommu_domain *domain;
+	int ret = 0;
+
+	if (type == IOMMU_DOMAIN_SVA)
+		return arm_smmu_sva_domain_alloc();
+
+	if (type != IOMMU_DOMAIN_UNMANAGED &&
+	    type != IOMMU_DOMAIN_DMA &&
+	    type != IOMMU_DOMAIN_DMA_FQ &&
+	    type != IOMMU_DOMAIN_IDENTITY)
+		return NULL;
+
+	/*
+	 * Allocate the domain and initialise some of its data structures.
+	 * We can't really finalise the domain unless a master is given.
+	 */
+	smmu_domain = kzalloc(sizeof(*smmu_domain), GFP_KERNEL);
+	if (!smmu_domain)
+		return NULL;
+	domain = &smmu_domain->domain;
+
+	domain->type = type;
+	domain->ops = arm_smmu_ops.default_domain_ops;
+
+	mutex_init(&smmu_domain->init_mutex);
+	INIT_LIST_HEAD(&smmu_domain->devices);
+	spin_lock_init(&smmu_domain->devices_lock);
+	INIT_LIST_HEAD(&smmu_domain->mmu_notifiers);
+
+	if (master) {
+		smmu_domain->smmu = master->smmu;
+		ret = arm_smmu_domain_finalise(domain, master, user_cfg);
+		if (ret) {
+			kfree(smmu_domain);
+			return NULL;
+		}
+	}
+
+	return domain;
+}
+
+static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
+{
+	return __arm_smmu_domain_alloc(type, NULL, NULL, NULL);
+}
+
+static struct iommu_domain *
+arm_smmu_domain_alloc_user(struct device *dev, struct iommu_domain *parent,
+			   const void *user_data)
+{
+	const struct iommu_hwpt_arm_smmuv3 *user_cfg = user_data;
+	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
+	unsigned type = IOMMU_DOMAIN_UNMANAGED;
+
+	return __arm_smmu_domain_alloc(type, NULL, master, user_cfg);
+}
+
 static struct iommu_ops arm_smmu_ops = {
 	.capable		= arm_smmu_capable,
 	.hw_info		= arm_smmu_hw_info,
 	.domain_alloc		= arm_smmu_domain_alloc,
+	.domain_alloc_user	= arm_smmu_domain_alloc_user,
 	.get_unmanaged_domain	= arm_smmu_get_unmanaged_domain,
 	.probe_device		= arm_smmu_probe_device,
 	.release_device		= arm_smmu_release_device,
-- 
2.39.2