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From:   Nicolin Chen <nicolinc@nvidia.com>
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Subject: [PATCH v2 06/17] iommu/arm-smmu-v3: Add arm_smmu_set/unset_dev_user_data
Date:   Tue, 9 May 2023 20:33:26 -0700
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Implement the new set_dev_user_data and unset_dev_user_data ops, by using
an xarray to store the stream pointer indexed by a given user Stream ID.
This will be used by the user cache invalidation hypercall, to check the
SID field of an ATC_INV command and replace it with the physical SID.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 44 +++++++++++++++++++++
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |  2 +
 include/uapi/linux/iommufd.h                | 10 +++++
 3 files changed, 56 insertions(+)

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 89daf50be87b..327819663547 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2746,6 +2746,46 @@ static void arm_smmu_release_device(struct device *dev)
 	kfree(master);
 }
 
+static int arm_smmu_set_dev_user_data(struct device *dev, const void *user_data)
+{
+	const struct iommu_device_data_arm_smmuv3 *user = user_data;
+	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
+	struct arm_smmu_stream *stream = &master->streams[0];
+	struct arm_smmu_device *smmu = master->smmu;
+	u32 sid_user = user->sid;
+	int ret = 0;
+
+	if (!sid_user)
+		return -EINVAL;
+
+	ret = xa_alloc(&smmu->streams_user, &sid_user, stream,
+			XA_LIMIT(sid_user, sid_user), GFP_KERNEL_ACCOUNT);
+	if (ret)
+		return ret;
+	stream->id_user = sid_user;
+	return 0;
+}
+
+static void arm_smmu_unset_dev_user_data(struct device *dev)
+{
+	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
+	struct arm_smmu_stream *stream = &master->streams[0];
+	struct arm_smmu_device *smmu = master->smmu;
+	u32 sid_user = stream->id_user;
+
+	if (!sid_user)
+		return;
+
+	xa_lock(&smmu->streams_user);
+	stream = __xa_erase(&smmu->streams_user, sid_user);
+	if (stream != master->streams) {
+		WARN_ON(__xa_alloc(&smmu->streams_user, &sid_user, stream,
+				   XA_LIMIT(sid_user, sid_user),
+				   GFP_KERNEL_ACCOUNT));
+	}
+	xa_unlock(&smmu->streams_user);
+}
+
 static struct iommu_group *arm_smmu_device_group(struct device *dev)
 {
 	struct iommu_group *group;
@@ -2873,6 +2913,9 @@ static struct iommu_ops arm_smmu_ops = {
 	.domain_alloc		= arm_smmu_domain_alloc,
 	.probe_device		= arm_smmu_probe_device,
 	.release_device		= arm_smmu_release_device,
+	.set_dev_user_data	= arm_smmu_set_dev_user_data,
+	.unset_dev_user_data	= arm_smmu_unset_dev_user_data,
+	.dev_user_data_len	= sizeof(struct iommu_device_data_arm_smmuv3),
 	.device_group		= arm_smmu_device_group,
 	.of_xlate		= arm_smmu_of_xlate,
 	.get_resv_regions	= arm_smmu_get_resv_regions,
@@ -3108,6 +3151,7 @@ static int arm_smmu_init_structures(struct arm_smmu_device *smmu)
 
 	mutex_init(&smmu->streams_mutex);
 	smmu->streams = RB_ROOT;
+	xa_init_flags(&smmu->streams_user, XA_FLAGS_ALLOC1 | XA_FLAGS_ACCOUNT);
 
 	ret = arm_smmu_init_queues(smmu);
 	if (ret)
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 5fa010c6fe20..1951a80af241 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -676,10 +676,12 @@ struct arm_smmu_device {
 
 	struct rb_root			streams;
 	struct mutex			streams_mutex;
+	struct xarray			streams_user;
 };
 
 struct arm_smmu_stream {
 	u32				id;
+	u32				id_user;
 	struct arm_smmu_master		*master;
 	struct rb_node			node;
 };
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index b1fe4c59ab82..2ecb6240ec69 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -592,6 +592,16 @@ struct iommu_hw_info {
 };
 #define IOMMU_DEVICE_GET_HW_INFO _IO(IOMMUFD_TYPE, IOMMUFD_CMD_DEVICE_GET_HW_INFO)
 
+/**
+ * struct iommu_device_data_arm_smmuv3 - ARM SMMUv3 specific device data
+ * @sid: The Stream ID that is assigned in the user space
+ *
+ * This should be passed via the VFIO_DEVICE_BIND_IOMMUFD ioctl.
+ */
+struct iommu_device_data_arm_smmuv3 {
+	__u32 sid;
+};
+
 /**
  * enum iommu_hwpt_intel_vtd_invalidate_flags - Flags for Intel VT-d
  *                                              stage-1 page table cache
-- 
2.40.1