[PATCH RFC v1 3/3] iommu/arm-smmu-v3: Implement set_rid_user and unset_rid_user

[Nicolin Chen]

Implement the new set_rid_user and unset_rid_user ops, by using an xarray
to store the stream pointer indexed by a given user space Stream ID. This
will be used by user cache invalidation hypercall, to check the SID field
of an ATC_INV command and replace it with the corresponding physical SID.

Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 45 +++++++++++++++++++++
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |  2 +
 2 files changed, 47 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 f2425b0f0cd6..17bb90e78547 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2843,6 +2843,48 @@ static void arm_smmu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
 	arm_smmu_sva_remove_dev_pasid(domain, dev, pasid);
 }
 
+static int arm_smmu_set_rid_user(struct device *dev, u32 rid, u32 rid_base)
+{
+	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 = rid_base | rid;
+	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 int arm_smmu_unset_rid_user(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 -ENODEV;
+
+	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);
+		return -EINVAL;
+	}
+	xa_unlock(&smmu->streams_user);
+	return 0;
+}
+
 static struct iommu_ops arm_smmu_ops = {
 	.capable		= arm_smmu_capable,
 	.domain_alloc		= arm_smmu_domain_alloc,
@@ -2854,6 +2896,8 @@ static struct iommu_ops arm_smmu_ops = {
 	.remove_dev_pasid	= arm_smmu_remove_dev_pasid,
 	.dev_enable_feat	= arm_smmu_dev_enable_feature,
 	.dev_disable_feat	= arm_smmu_dev_disable_feature,
+	.set_rid_user		= arm_smmu_set_rid_user,
+	.unset_rid_user		= arm_smmu_unset_rid_user,
 	.page_response		= arm_smmu_page_response,
 	.def_domain_type	= arm_smmu_def_domain_type,
 	.pgsize_bitmap		= -1UL, /* Restricted during device attach */
@@ -3082,6 +3126,7 @@ 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 8d772ea8a583..8ccea2e84bbb 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -674,10 +674,12 @@ 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;
 };
-- 
2.40.0