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

Nicolin Chen
2025-05-18T03:47:05Z

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@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
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