[PATCH RFCv1 05/14] iommufd: Add IOMMUFD_OBJ_VIOMMU and IOMMUFD_CMD_VIOMMU_ALLOC

[Nicolin Chen <nicolinc@nvidia.com>]

Corresponding to the new iommufd_viommu core structure that represents a
vIOMMU instance in the user space for HW-accelerated features, add a new
IOMMUFD_OBJ_VIOMMU and its ioctl for user space to allocate it.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/iommufd/iommufd_private.h |  3 +
 drivers/iommu/iommufd/main.c            |  6 ++
 drivers/iommu/iommufd/viommu.c          | 83 +++++++++++++++++++++++++
 include/linux/iommufd.h                 |  1 +
 include/uapi/linux/iommufd.h            | 30 +++++++++
 5 files changed, 123 insertions(+)

diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index eccc565ed38e..ae90b4493109 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -424,6 +424,9 @@ void iopt_remove_access(struct io_pagetable *iopt,
 			u32 iopt_access_list_id);
 void iommufd_access_destroy_object(struct iommufd_object *obj);
 
+int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd);
+void iommufd_viommu_destroy(struct iommufd_object *obj);
+
 #ifdef CONFIG_IOMMUFD_TEST
 int iommufd_test(struct iommufd_ucmd *ucmd);
 void iommufd_selftest_destroy(struct iommufd_object *obj);
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index 5187942b375d..9de7e3e63ce4 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -323,6 +323,7 @@ union ucmd_buffer {
 	struct iommu_hwpt_set_dirty_tracking set_dirty_tracking;
 	struct iommu_ioas_alloc alloc;
 	struct iommu_ioas_allow_iovas allow_iovas;
+	struct iommu_viommu_alloc viommu;
 	struct iommu_ioas_copy ioas_copy;
 	struct iommu_ioas_iova_ranges iova_ranges;
 	struct iommu_ioas_map map;
@@ -378,6 +379,8 @@ static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
 		 val64),
 	IOCTL_OP(IOMMU_VFIO_IOAS, iommufd_vfio_ioas, struct iommu_vfio_ioas,
 		 __reserved),
+	IOCTL_OP(IOMMU_VIOMMU_ALLOC, iommufd_viommu_alloc_ioctl,
+		 struct iommu_viommu_alloc, out_viommu_id),
 #ifdef CONFIG_IOMMUFD_TEST
 	IOCTL_OP(IOMMU_TEST_CMD, iommufd_test, struct iommu_test_cmd, last),
 #endif
@@ -510,6 +513,9 @@ static const struct iommufd_object_ops iommufd_object_ops[] = {
 		.destroy = iommufd_hwpt_nested_destroy,
 		.abort = iommufd_hwpt_nested_abort,
 	},
+	[IOMMUFD_OBJ_VIOMMU] = {
+		.destroy = iommufd_viommu_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 3886b1dd1f13..079e0ff79942 100644
--- a/drivers/iommu/iommufd/viommu.c
+++ b/drivers/iommu/iommufd/viommu.c
@@ -19,3 +19,86 @@
 	}
 
 viommu_struct_alloc(viommu);
+
+void iommufd_viommu_destroy(struct iommufd_object *obj)
+{
+	struct iommufd_viommu *viommu =
+		container_of(obj, struct iommufd_viommu, obj);
+
+	if (viommu->ops && viommu->ops->free)
+		viommu->ops->free(viommu);
+	refcount_dec(&viommu->hwpt->common.obj.users);
+}
+
+int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
+{
+	struct iommu_viommu_alloc *cmd = ucmd->cmd;
+	struct iommufd_hwpt_paging *hwpt_paging;
+	struct iommu_device *iommu_dev;
+	struct iommufd_viommu *viommu;
+	struct iommufd_device *idev;
+	int rc;
+
+	if (cmd->flags)
+		return -EOPNOTSUPP;
+
+	idev = iommufd_get_device(ucmd, cmd->dev_id);
+	if (IS_ERR(idev))
+		return PTR_ERR(idev);
+	iommu_dev = idev->dev->iommu->iommu_dev;
+
+	if (!iommu_dev->ops->viommu_alloc) {
+		rc = -EOPNOTSUPP;
+		goto out_put_idev;
+	}
+
+	hwpt_paging = iommufd_get_hwpt_paging(ucmd, cmd->hwpt_id);
+	if (IS_ERR(hwpt_paging)) {
+		rc = PTR_ERR(hwpt_paging);
+		goto out_put_idev;
+	}
+
+	if (!hwpt_paging->nest_parent) {
+		rc = -EINVAL;
+		goto out_put_hwpt;
+	}
+
+	viommu = iommu_dev->ops->viommu_alloc(idev->dev, cmd->type,
+					      hwpt_paging->common.domain);
+	if (IS_ERR(viommu)) {
+		rc = PTR_ERR(viommu);
+		goto out_put_hwpt;
+	}
+
+	/* iommufd_object_finalize will store the viommu->obj.id */
+	rc = xa_alloc(&ucmd->ictx->objects, &viommu->obj.id, XA_ZERO_ENTRY,
+		      xa_limit_31b, GFP_KERNEL_ACCOUNT);
+	if (rc)
+		goto out_free;
+
+	viommu->obj.type = IOMMUFD_OBJ_VIOMMU;
+	viommu->type = cmd->type;
+
+	viommu->ictx = ucmd->ictx;
+	viommu->hwpt = hwpt_paging;
+	viommu->iommu_dev = idev->dev->iommu->iommu_dev;
+	cmd->out_viommu_id = viommu->obj.id;
+	rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));
+	if (rc)
+		goto out_erase_xa;
+	iommufd_object_finalize(ucmd->ictx, &viommu->obj);
+	refcount_inc(&viommu->hwpt->common.obj.users);
+	goto out_put_hwpt;
+
+out_erase_xa:
+	xa_erase(&ucmd->ictx->objects, viommu->obj.id);
+out_free:
+	if (viommu->ops && viommu->ops->free)
+		viommu->ops->free(viommu);
+	kfree(viommu);
+out_put_hwpt:
+	iommufd_put_object(ucmd->ictx, &hwpt_paging->common.obj);
+out_put_idev:
+	iommufd_put_object(ucmd->ictx, &idev->obj);
+	return rc;
+}
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index 650acfac307a..dec10c6bb261 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -28,6 +28,7 @@ enum iommufd_object_type {
 	IOMMUFD_OBJ_HWPT_NESTED,
 	IOMMUFD_OBJ_IOAS,
 	IOMMUFD_OBJ_ACCESS,
+	IOMMUFD_OBJ_VIOMMU,
 #ifdef CONFIG_IOMMUFD_TEST
 	IOMMUFD_OBJ_SELFTEST,
 #endif
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 1dfeaa2e649e..2b0825d69846 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -50,6 +50,7 @@ enum {
 	IOMMUFD_CMD_HWPT_SET_DIRTY_TRACKING,
 	IOMMUFD_CMD_HWPT_GET_DIRTY_BITMAP,
 	IOMMUFD_CMD_HWPT_INVALIDATE,
+	IOMMUFD_CMD_VIOMMU_ALLOC,
 };
 
 /**
@@ -692,4 +693,33 @@ struct iommu_hwpt_invalidate {
 	__u32 __reserved;
 };
 #define IOMMU_HWPT_INVALIDATE _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_INVALIDATE)
+
+/**
+ * enum iommu_viommu_type - VIOMMU Type
+ * @IOMMU_VIOMMU_TEGRA241_CMDQV: NVIDIA Tegra241 CMDQV Extension for SMMUv3
+ */
+enum iommu_viommu_type {
+	IOMMU_VIOMMU_TYPE_TEGRA241_CMDQV,
+};
+
+/**
+ * struct iommu_viommu_alloc - ioctl(IOMMU_VIOMMU_ALLOC)
+ * @size: sizeof(struct iommu_viommu_alloc)
+ * @flags: Must be 0
+ * @type: Type of the VIOMMU object. Must be defined in enum iommu_viommu_type
+ * @dev_id: The device to allocate this virtual IOMMU for
+ * @hwpt_id: ID of a nested parent HWPT
+ * @out_viommu_id: Output virtual IOMMU ID for the allocated object
+ *
+ * Allocate an virtual IOMMU object that holds a (shared) nested parent HWPT
+ */
+struct iommu_viommu_alloc {
+	__u32 size;
+	__u32 flags;
+	__u32 type;
+	__u32 dev_id;
+	__u32 hwpt_id;
+	__u32 out_viommu_id;
+};
+#define IOMMU_VIOMMU_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VIOMMU_ALLOC)
 #endif
-- 
2.43.0