[PATCH RFCv1 12/14] iommufd: Add IOMMUFD_OBJ_VQUEUE and IOMMUFD_CMD_VQUEUE_ALLOC

[Nicolin Chen]

Introduce a new IOMMUFD_OBJ_VQUEU to represent a virtual command queue
instance. And add a new ioctl for user space to allocate it.

As an initial version, ddd IOMMU_VQUEUE_DATA_TEGRA241_CMDQV to the enum
iommu_vqueue_data_type and the corresponding iommu_vqueue_tegra241_cmdqv
data structure.

Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
---
 drivers/iommu/iommufd/iommufd_private.h |  2 +
 drivers/iommu/iommufd/main.c            |  6 +++
 drivers/iommu/iommufd/viommu.c          | 72 +++++++++++++++++++++++++
 include/linux/iommufd.h                 |  1 +
 include/uapi/linux/iommufd.h            | 48 +++++++++++++++++
 5 files changed, 129 insertions(+)

diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 9ba8f4ecc221..c994f2db3052 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -436,6 +436,8 @@ iommufd_get_viommu(struct iommufd_ucmd *ucmd, u32 id)
 int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd);
 void iommufd_viommu_destroy(struct iommufd_object *obj);
 int iommufd_viommu_set_device_id(struct iommufd_ucmd *ucmd);
+int iommufd_vqueue_alloc_ioctl(struct iommufd_ucmd *ucmd);
+void iommufd_vqueue_destroy(struct iommufd_object *obj);
 
 #ifdef CONFIG_IOMMUFD_TEST
 int iommufd_test(struct iommufd_ucmd *ucmd);
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index 16efc3346a2a..96ef81530809 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -324,6 +324,7 @@ union ucmd_buffer {
 	struct iommu_ioas_alloc alloc;
 	struct iommu_ioas_allow_iovas allow_iovas;
 	struct iommu_viommu_alloc viommu;
+	struct iommu_vqueue_alloc vqueue;
 	struct iommu_ioas_copy ioas_copy;
 	struct iommu_ioas_iova_ranges iova_ranges;
 	struct iommu_ioas_map map;
@@ -383,6 +384,8 @@ static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
 		 struct iommu_viommu_alloc, out_viommu_id),
 	IOCTL_OP(IOMMU_VIOMMU_SET_DEV_ID, iommufd_viommu_set_device_id,
 		 struct iommu_viommu_set_dev_id, id),
+	IOCTL_OP(IOMMU_VQUEUE_ALLOC, iommufd_vqueue_alloc_ioctl,
+		 struct iommu_vqueue_alloc, data_uptr),
 #ifdef CONFIG_IOMMUFD_TEST
 	IOCTL_OP(IOMMU_TEST_CMD, iommufd_test, struct iommu_test_cmd, last),
 #endif
@@ -518,6 +521,9 @@ static const struct iommufd_object_ops iommufd_object_ops[] = {
 	[IOMMUFD_OBJ_VIOMMU] = {
 		.destroy = iommufd_viommu_destroy,
 	},
+	[IOMMUFD_OBJ_VQUEUE] = {
+		.destroy = iommufd_vqueue_destroy,
+	},
 #ifdef CONFIG_IOMMUFD_TEST
 	[IOMMUFD_OBJ_SELFTEST] = {
 		.destroy = iommufd_selftest_destroy,
diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c
index 8894878c1e73..56c9ea818bfa 100644
--- a/drivers/iommu/iommufd/viommu.c
+++ b/drivers/iommu/iommufd/viommu.c
@@ -161,3 +161,75 @@ int iommufd_viommu_set_device_id(struct iommufd_ucmd *ucmd)
 	iommufd_put_object(ucmd->ictx, &idev->obj);
 	return rc;
 }
+
+void iommufd_vqueue_destroy(struct iommufd_object *obj)
+{
+	struct iommufd_vqueue *vqueue =
+		container_of(obj, struct iommufd_vqueue, obj);
+	struct iommufd_viommu *viommu = vqueue->viommu;
+
+	if (viommu->ops->vqueue_free)
+		viommu->ops->vqueue_free(vqueue);
+	refcount_dec(&viommu->obj.users);
+}
+
+int iommufd_vqueue_alloc_ioctl(struct iommufd_ucmd *ucmd)
+{
+	struct iommu_vqueue_alloc *cmd = ucmd->cmd;
+	const struct iommu_user_data user_data = {
+		.type = cmd->data_type,
+		.uptr = u64_to_user_ptr(cmd->data_uptr),
+		.len = cmd->data_len,
+	};
+	struct iommufd_vqueue *vqueue;
+	struct iommufd_viommu *viommu;
+	int rc;
+
+	if (cmd->flags)
+		return -EOPNOTSUPP;
+	if (!cmd->data_len)
+		return -EINVAL;
+
+	viommu = iommufd_get_viommu(ucmd, cmd->viommu_id);
+	if (IS_ERR(viommu))
+		return PTR_ERR(viommu);
+
+	if (!viommu->ops || !viommu->ops->vqueue_alloc) {
+		rc = -EOPNOTSUPP;
+		goto out_put_viommu;
+	}
+
+	vqueue = viommu->ops->vqueue_alloc(
+		viommu, user_data.len ? &user_data : NULL);
+	if (IS_ERR(vqueue)) {
+		rc = PTR_ERR(vqueue);
+		goto out_put_viommu;
+	}
+
+	/* iommufd_object_finalize will store the vqueue->obj.id */
+	rc = xa_alloc(&ucmd->ictx->objects, &vqueue->obj.id, XA_ZERO_ENTRY,
+		      xa_limit_31b, GFP_KERNEL_ACCOUNT);
+	if (rc)
+		goto out_free;
+
+	vqueue->obj.type = IOMMUFD_OBJ_VQUEUE;
+
+	vqueue->ictx = ucmd->ictx;
+	vqueue->viommu = viommu;
+	cmd->out_vqueue_id = vqueue->obj.id;
+	rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));
+	if (rc)
+		goto out_erase_xa;
+	iommufd_object_finalize(ucmd->ictx, &vqueue->obj);
+	refcount_inc(&viommu->obj.users);
+	goto out_put_viommu;
+
+out_erase_xa:
+	xa_erase(&ucmd->ictx->objects, vqueue->obj.id);
+out_free:
+	if (viommu->ops->vqueue_free)
+		viommu->ops->vqueue_free(vqueue);
+out_put_viommu:
+	iommufd_put_object(ucmd->ictx, &viommu->obj);
+	return rc;
+}
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index 5b97b04aa145..707b6d4b20a3 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -31,6 +31,7 @@ enum iommufd_object_type {
 	IOMMUFD_OBJ_IOAS,
 	IOMMUFD_OBJ_ACCESS,
 	IOMMUFD_OBJ_VIOMMU,
+	IOMMUFD_OBJ_VQUEUE,
 #ifdef CONFIG_IOMMUFD_TEST
 	IOMMUFD_OBJ_SELFTEST,
 #endif
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index eaa192de63d3..95abe3100e3b 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -52,6 +52,7 @@ enum {
 	IOMMUFD_CMD_HWPT_INVALIDATE,
 	IOMMUFD_CMD_VIOMMU_ALLOC,
 	IOMMUFD_CMD_VIOMMU_SET_DEV_ID,
+	IOMMUFD_CMD_VQUEUE_ALLOC,
 };
 
 /**
@@ -742,4 +743,51 @@ struct iommu_viommu_set_dev_id {
 	__aligned_u64 id;
 };
 #define IOMMU_VIOMMU_SET_DEV_ID _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VIOMMU_SET_DEV_ID)
+
+/**
+ * struct iommu_vqueue_tegra241_cmdqv - NVIDIA Tegra241's Virtual Command Queue
+ *                                      for its CMDQV Extension for ARM SMMUv3
+ *                                      (IOMMU_VQUEUE_DATA_TEGRA241_CMDQV)
+ * @vcmdq_id: logical ID of a virtual command queue in the VIOMMU instance
+ * @vcmdq_log2size: (1 << @vcmdq_log2size) will be the size of the vcmdq
+ * @vcmdq_base: guest physical address (IPA) to the vcmdq base address
+ */
+struct iommu_vqueue_tegra241_cmdqv {
+	__u32 vcmdq_id;
+	__u32 vcmdq_log2size;
+	__aligned_u64 vcmdq_base;
+};
+
+/**
+ * enum iommu_vqueue_data_type - VQUEUE Data Type
+ * @IOMMU_VQUEUE_DATA_TEGRA241_CMDQV: NVIDIA Tegra241 CMDQV Extension for SMMUv3
+ */
+enum iommu_vqueue_data_type {
+	IOMMU_VQUEUE_DATA_TEGRA241_CMDQV,
+};
+
+/**
+ * struct iommu_vqueue_alloc - ioctl(IOMMU_VQUEUE_ALLOC)
+ * @size: sizeof(struct iommu_vqueue_alloc)
+ * @flags: Must be 0
+ * @viommu_id: viommu ID to associate the virtual queue with
+ * @out_vqueue_id: The ID of the new virtual queue
+ * @data_type: One of enum iommu_vqueue_data_type
+ * @data_len: Length of the type specific data
+ * @data_uptr: User pointer to the type specific data
+ *
+ * Allocate an virtual queue object for driver-specific HW-accelerated queue
+ */
+
+struct iommu_vqueue_alloc {
+	__u32 size;
+	__u32 flags;
+	__u32 viommu_id;
+	__u32 out_vqueue_id;
+	__u32 data_type;
+	__u32 data_len;
+	__aligned_u64 data_uptr;
+};
+#define IOMMU_VQUEUE_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VQUEUE_ALLOC)
+
 #endif
-- 
2.43.0