[PATCH v5 12/29] iommufd/viommu: Add driver-allocated vDEVICE support

[Nicolin Chen]

To allow IOMMU drivers to allocate own vDEVICE structures, move the struct
iommufd_vdevice to the public header and provide a pair of viommu ops.

The iommufd_vdevice_alloc_ioctl will prioritize the callback function from
the viommu ops, i.e. a driver-allocated vDEVICE.

Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
---
 drivers/iommu/iommufd/iommufd_private.h |  8 ------
 include/linux/iommufd.h                 | 36 +++++++++++++++++++++++++
 drivers/iommu/iommufd/viommu.c          | 10 ++++++-
 3 files changed, 45 insertions(+), 9 deletions(-)

diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 44286216ac5a..35088478cb07 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -604,14 +604,6 @@ void iommufd_viommu_destroy(struct iommufd_object *obj);
 int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd);
 void iommufd_vdevice_destroy(struct iommufd_object *obj);
 
-struct iommufd_vdevice {
-	struct iommufd_object obj;
-	struct iommufd_ctx *ictx;
-	struct iommufd_viommu *viommu;
-	struct device *dev;
-	u64 id; /* per-vIOMMU virtual ID */
-};
-
 #ifdef CONFIG_IOMMUFD_TEST
 int iommufd_test(struct iommufd_ucmd *ucmd);
 void iommufd_selftest_destroy(struct iommufd_object *obj);
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index a07466333c48..266ac6805213 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -125,6 +125,14 @@ struct iommufd_viommu {
 	unsigned int type;
 };
 
+struct iommufd_vdevice {
+	struct iommufd_object obj;
+	struct iommufd_ctx *ictx;
+	struct iommufd_viommu *viommu;
+	struct device *dev;
+	u64 id; /* per-vIOMMU virtual ID */
+};
+
 /**
  * struct iommufd_viommu_ops - vIOMMU specific operations
  * @destroy: Clean up all driver-specific parts of an iommufd_viommu. The memory
@@ -141,6 +149,15 @@ struct iommufd_viommu {
  *                    array->entry_num to report the number of handled requests.
  *                    The data structure of the array entry must be defined in
  *                    include/uapi/linux/iommufd.h
+ * @vdevice_alloc: Allocate a vDEVICE object and init its driver-level structure
+ *                 or HW procedure. Note that the core-level structure is filled
+ *                 by the iommufd core after calling this op. @virt_id carries a
+ *                 per-vIOMMU virtual ID (refer to struct iommu_vdevice_alloc in
+ *                 include/uapi/linux/iommufd.h) for the driver to initialize HW
+ *                 for an attached physical device.
+ * @vdevice_destroy: Clean up all driver-specific parts of an iommufd_vdevice.
+ *                   The memory of the vDEVICE will be free-ed by iommufd core
+ *                   after calling this op
  */
 struct iommufd_viommu_ops {
 	void (*destroy)(struct iommufd_viommu *viommu);
@@ -149,6 +166,11 @@ struct iommufd_viommu_ops {
 		const struct iommu_user_data *user_data);
 	int (*cache_invalidate)(struct iommufd_viommu *viommu,
 				struct iommu_user_data_array *array);
+	struct iommufd_vdevice *(*vdevice_alloc)(struct iommufd_ucmd *ucmd,
+						 struct iommufd_viommu *viommu,
+						 struct device *dev,
+						 u64 virt_id);
+	void (*vdevice_destroy)(struct iommufd_vdevice *vdev);
 };
 
 #if IS_ENABLED(CONFIG_IOMMUFD)
@@ -276,4 +298,18 @@ static inline int iommufd_viommu_report_event(struct iommufd_viommu *viommu,
 		}                                                              \
 		ret;                                                           \
 	})
+
+#define iommufd_vdevice_alloc(ucmd, viommu, drv_struct, member)                \
+	({                                                                     \
+		drv_struct *ret;                                               \
+									       \
+		static_assert(__same_type(struct iommufd_viommu, *viommu));    \
+		ret = (drv_struct *)__iommufd_object_alloc_ucmd(               \
+			ucmd, ret, IOMMUFD_OBJ_VDEVICE, member.obj);           \
+		if (!IS_ERR(ret)) {                                            \
+			ret->member.viommu = viommu;                           \
+			ret->member.ictx = viommu->ictx;                       \
+		}                                                              \
+		ret;                                                           \
+	})
 #endif
diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c
index 662f5c1b1935..7248fb7c7baf 100644
--- a/drivers/iommu/iommufd/viommu.c
+++ b/drivers/iommu/iommufd/viommu.c
@@ -95,6 +95,9 @@ void iommufd_vdevice_destroy(struct iommufd_object *obj)
 		container_of(obj, struct iommufd_vdevice, obj);
 	struct iommufd_viommu *viommu = vdev->viommu;
 
+	if (viommu->ops && viommu->ops->vdevice_destroy)
+		viommu->ops->vdevice_destroy(vdev);
+
 	/* xa_cmpxchg is okay to fail if alloc failed xa_cmpxchg previously */
 	xa_cmpxchg(&viommu->vdevs, vdev->id, vdev, NULL, GFP_KERNEL);
 	refcount_dec(&viommu->obj.users);
@@ -129,7 +132,12 @@ int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd)
 		goto out_put_idev;
 	}
 
-	vdev = iommufd_object_alloc_ucmd(ucmd, vdev, IOMMUFD_OBJ_VDEVICE);
+	if (viommu->ops && viommu->ops->vdevice_alloc)
+		vdev = viommu->ops->vdevice_alloc(ucmd, viommu, idev->dev,
+						  virt_id);
+	else
+		vdev = iommufd_object_alloc_ucmd(ucmd, vdev,
+						 IOMMUFD_OBJ_VDEVICE);
 	if (IS_ERR(vdev)) {
 		rc = PTR_ERR(vdev);
 		goto out_put_idev;
-- 
2.43.0