[PATCH v3 15/15] vfio: Add struct device to vfio_device
From: Kevin Tian
Date: Thu Sep 08 2022 - 23:08:37 EST
From: Yi Liu <yi.l.liu@xxxxxxxxx>
and replace kref. With it a 'vfio-dev/vfioX' node is created under the
sysfs path of the parent, indicating the device is bound to a vfio
driver, e.g.:
/sys/devices/pci0000\:6f/0000\:6f\:01.0/vfio-dev/vfio0
It is also a preparatory step toward adding cdev for supporting future
device-oriented uAPI.
Add Documentation/ABI/testing/sysfs-devices-vfio-dev.
Also take this chance to rename chardev 'vfio' to 'vfio-group' in
/proc/devices.
Suggested-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
Signed-off-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
---
.../ABI/testing/sysfs-devices-vfio-dev | 8 +++
MAINTAINERS | 1 +
drivers/vfio/vfio_main.c | 67 +++++++++++++++----
include/linux/vfio.h | 6 +-
4 files changed, 67 insertions(+), 15 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-devices-vfio-dev
diff --git a/Documentation/ABI/testing/sysfs-devices-vfio-dev b/Documentation/ABI/testing/sysfs-devices-vfio-dev
new file mode 100644
index 000000000000..e21424fd9666
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-devices-vfio-dev
@@ -0,0 +1,8 @@
+What: /sys/.../<device>/vfio-dev/vfioX/
+Date: September 2022
+Contact: Yi Liu <yi.l.liu@xxxxxxxxx>
+Description:
+ This directory is created when the device is bound to a
+ vfio driver. The layout under this directory matches what
+ exists for a standard 'struct device'. 'X' is a unique
+ index marking this device in vfio.
diff --git a/MAINTAINERS b/MAINTAINERS
index d30f26e07cd3..02c8f11b1c17 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -21312,6 +21312,7 @@ R: Cornelia Huck <cohuck@xxxxxxxxxx>
L: kvm@xxxxxxxxxxxxxxx
S: Maintained
T: git git://github.com/awilliam/linux-vfio.git
+F: Documentation/ABI/testing/sysfs-devices-vfio-dev
F: Documentation/driver-api/vfio.rst
F: drivers/vfio/
F: include/linux/vfio.h
diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index 37cbd10f3faf..cd23d35c878c 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -49,6 +49,8 @@ static struct vfio {
struct mutex group_lock; /* locks group_list */
struct ida group_ida;
dev_t group_devt;
+ struct class *device_class;
+ struct ida device_ida;
} vfio;
struct vfio_iommu_driver {
@@ -485,12 +487,13 @@ static struct vfio_device *vfio_group_get_device(struct vfio_group *group,
* VFIO driver API
*/
/* Release helper called by vfio_put_device() */
-void vfio_device_release(struct kref *kref)
+static void vfio_device_release(struct device *dev)
{
struct vfio_device *device =
- container_of(kref, struct vfio_device, kref);
+ container_of(dev, struct vfio_device, device);
vfio_release_device_set(device);
+ ida_free(&vfio.device_ida, device->index);
/*
* kvfree() cannot be done here due to a life cycle mess in
@@ -500,7 +503,6 @@ void vfio_device_release(struct kref *kref)
*/
device->ops->release(device);
}
-EXPORT_SYMBOL_GPL(vfio_device_release);
/*
* Alloc and initialize vfio_device so it can be registered to vfio
@@ -548,6 +550,13 @@ int vfio_init_device(struct vfio_device *device, struct device *dev,
{
int ret;
+ ret = ida_alloc_max(&vfio.device_ida, MINORMASK, GFP_KERNEL);
+ if (ret < 0) {
+ dev_dbg(dev, "Error to alloc index\n");
+ return ret;
+ }
+
+ device->index = ret;
init_completion(&device->comp);
device->dev = dev;
device->ops = ops;
@@ -558,11 +567,15 @@ int vfio_init_device(struct vfio_device *device, struct device *dev,
goto out_uninit;
}
- kref_init(&device->kref);
+ device_initialize(&device->device);
+ device->device.release = vfio_device_release;
+ device->device.class = vfio.device_class;
+ device->device.parent = device->dev;
return 0;
out_uninit:
vfio_release_device_set(device);
+ ida_free(&vfio.device_ida, device->index);
return ret;
}
EXPORT_SYMBOL_GPL(vfio_init_device);
@@ -659,6 +672,7 @@ static int __vfio_register_dev(struct vfio_device *device,
struct vfio_group *group)
{
struct vfio_device *existing_device;
+ int ret;
if (IS_ERR(group))
return PTR_ERR(group);
@@ -675,16 +689,21 @@ static int __vfio_register_dev(struct vfio_device *device,
dev_WARN(device->dev, "Device already exists on group %d\n",
iommu_group_id(group->iommu_group));
vfio_device_put_registration(existing_device);
- if (group->type == VFIO_NO_IOMMU ||
- group->type == VFIO_EMULATED_IOMMU)
- iommu_group_remove_device(device->dev);
- vfio_group_put(group);
- return -EBUSY;
+ ret = -EBUSY;
+ goto err_out;
}
/* Our reference on group is moved to the device */
device->group = group;
+ ret = dev_set_name(&device->device, "vfio%d", device->index);
+ if (ret)
+ goto err_out;
+
+ ret = device_add(&device->device);
+ if (ret)
+ goto err_out;
+
/* Refcounting can't start until the driver calls register */
refcount_set(&device->refcount, 1);
@@ -693,6 +712,12 @@ static int __vfio_register_dev(struct vfio_device *device,
mutex_unlock(&group->device_lock);
return 0;
+err_out:
+ if (group->type == VFIO_NO_IOMMU ||
+ group->type == VFIO_EMULATED_IOMMU)
+ iommu_group_remove_device(device->dev);
+ vfio_group_put(group);
+ return ret;
}
int vfio_register_group_dev(struct vfio_device *device)
@@ -779,6 +804,9 @@ void vfio_unregister_group_dev(struct vfio_device *device)
list_del(&device->group_next);
mutex_unlock(&group->device_lock);
+ /* Balances device_add in register path */
+ device_del(&device->device);
+
if (group->type == VFIO_NO_IOMMU || group->type == VFIO_EMULATED_IOMMU)
iommu_group_remove_device(device->dev);
@@ -2362,6 +2390,7 @@ static int __init vfio_init(void)
int ret;
ida_init(&vfio.group_ida);
+ ida_init(&vfio.device_ida);
mutex_init(&vfio.group_lock);
mutex_init(&vfio.iommu_drivers_lock);
INIT_LIST_HEAD(&vfio.group_list);
@@ -2377,12 +2406,20 @@ static int __init vfio_init(void)
vfio.class = class_create(THIS_MODULE, "vfio");
if (IS_ERR(vfio.class)) {
ret = PTR_ERR(vfio.class);
- goto err_class;
+ goto err_group_class;
}
vfio.class->devnode = vfio_devnode;
- ret = alloc_chrdev_region(&vfio.group_devt, 0, MINORMASK + 1, "vfio");
+ /* /sys/class/vfio-dev/vfioX */
+ vfio.device_class = class_create(THIS_MODULE, "vfio-dev");
+ if (IS_ERR(vfio.device_class)) {
+ ret = PTR_ERR(vfio.device_class);
+ goto err_dev_class;
+ }
+
+ ret = alloc_chrdev_region(&vfio.group_devt, 0, MINORMASK + 1,
+ "vfio-group");
if (ret)
goto err_alloc_chrdev;
@@ -2398,9 +2435,12 @@ static int __init vfio_init(void)
err_driver_register:
unregister_chrdev_region(vfio.group_devt, MINORMASK + 1);
err_alloc_chrdev:
+ class_destroy(vfio.device_class);
+ vfio.device_class = NULL;
+err_dev_class:
class_destroy(vfio.class);
vfio.class = NULL;
-err_class:
+err_group_class:
misc_deregister(&vfio_dev);
return ret;
}
@@ -2412,8 +2452,11 @@ static void __exit vfio_cleanup(void)
#ifdef CONFIG_VFIO_NOIOMMU
vfio_unregister_iommu_driver(&vfio_noiommu_ops);
#endif
+ ida_destroy(&vfio.device_ida);
ida_destroy(&vfio.group_ida);
unregister_chrdev_region(vfio.group_devt, MINORMASK + 1);
+ class_destroy(vfio.device_class);
+ vfio.device_class = NULL;
class_destroy(vfio.class);
vfio.class = NULL;
misc_deregister(&vfio_dev);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 3cf857b1eec7..ee399a768070 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -47,7 +47,8 @@ struct vfio_device {
struct kvm *kvm;
/* Members below here are private, not for driver use */
- struct kref kref; /* object life cycle */
+ unsigned int index;
+ struct device device; /* device.kref covers object life circle */
refcount_t refcount; /* user count on registered device*/
unsigned int open_count;
struct completion comp;
@@ -178,10 +179,9 @@ struct vfio_device *_vfio_alloc_device(size_t size, struct device *dev,
int vfio_init_device(struct vfio_device *device, struct device *dev,
const struct vfio_device_ops *ops);
void vfio_free_device(struct vfio_device *device);
-void vfio_device_release(struct kref *kref);
static inline void vfio_put_device(struct vfio_device *device)
{
- kref_put(&device->kref, vfio_device_release);
+ put_device(&device->device);
}
int vfio_register_group_dev(struct vfio_device *device);
--
2.21.3