From: Yi Liu <[email protected]>
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 <[email protected]>
Signed-off-by: Yi Liu <[email protected]>
Signed-off-by: Kevin Tian <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
---
.../ABI/testing/sysfs-devices-vfio-dev | 8 +++
drivers/vfio/vfio_main.c | 67 +++++++++++++++----
include/linux/vfio.h | 6 +-
3 files changed, 66 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 <[email protected]>
+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/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index bfa675d314ab..141f55c3faf5 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -46,6 +46,8 @@ 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 {
@@ -483,12 +485,13 @@ 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
@@ -498,7 +501,6 @@ 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
@@ -546,6 +548,13 @@ 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;
@@ -556,11 +565,15 @@ 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);
@@ -657,6 +670,7 @@ 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);
@@ -673,16 +687,21 @@ 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);
@@ -692,6 +711,12 @@ 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)
group->dev_counter--;
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);
@@ -2145,6 +2173,7 @@ 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);
@@ -2160,12 +2189,20 @@ 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;
@@ -2181,9 +2218,12 @@ 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;
}
@@ -2195,8 +2235,11 @@ 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 f03447c8774d..5c13f74da1bb 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -45,7 +45,8 @@ 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;
@@ -154,10 +155,9 @@ 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
> From: Tian, Kevin <[email protected]>
> Sent: Thursday, September 1, 2022 10:38 PM
>
> 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 <[email protected]>
> +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.
This missed an update to MAINTAINER file:
diff --git a/MAINTAINERS b/MAINTAINERS
index 589517372408..3fc8c599f4f2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -21310,6 +21310,7 @@ R: Cornelia Huck <[email protected]>
L: [email protected]
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
Alex, I sent a wrong version w/o fixing two checkpatch warnings (this
and the one in patch12). Please let me know whether you want me to
resend.
Thanks
Kevin
Hi Kevin,
On 9/1/22 16:37, Kevin Tian wrote:
> From: Yi Liu <[email protected]>
>
> 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 <[email protected]>
> Signed-off-by: Yi Liu <[email protected]>
> Signed-off-by: Kevin Tian <[email protected]>
> Reviewed-by: Jason Gunthorpe <[email protected]>
> ---
> .../ABI/testing/sysfs-devices-vfio-dev | 8 +++
> drivers/vfio/vfio_main.c | 67 +++++++++++++++----
> include/linux/vfio.h | 6 +-
> 3 files changed, 66 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 <[email protected]>
> +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/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
> index bfa675d314ab..141f55c3faf5 100644
> --- a/drivers/vfio/vfio_main.c
> +++ b/drivers/vfio/vfio_main.c
> @@ -46,6 +46,8 @@ 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 {
> @@ -483,12 +485,13 @@ 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
> @@ -498,7 +501,6 @@ 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
> @@ -546,6 +548,13 @@ 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;
> @@ -556,11 +565,15 @@ 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);
> @@ -657,6 +670,7 @@ 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);
> @@ -673,16 +687,21 @@ 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);
>
> @@ -692,6 +711,12 @@ 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)
> group->dev_counter--;
> 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);
>
> @@ -2145,6 +2173,7 @@ 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);
> @@ -2160,12 +2189,20 @@ 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;
>
> @@ -2181,9 +2218,12 @@ 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;
> }
> @@ -2195,8 +2235,11 @@ 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 f03447c8774d..5c13f74da1bb 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -45,7 +45,8 @@ 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;
I am not totally clear about remaining 'struct device *dev;' in
vfio_device struct. I see it used in some places. Is it supposed to
disappear at some point?
> @@ -154,10 +155,9 @@ 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);
Thanks
Eric
On 2022/9/8 17:06, Eric Auger wrote:
> Hi Kevin,
>
> On 9/1/22 16:37, Kevin Tian wrote:
>> From: Yi Liu <[email protected]>
>>
>> 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 <[email protected]>
>> Signed-off-by: Yi Liu <[email protected]>
>> Signed-off-by: Kevin Tian <[email protected]>
>> Reviewed-by: Jason Gunthorpe <[email protected]>
>> ---
>> .../ABI/testing/sysfs-devices-vfio-dev | 8 +++
>> drivers/vfio/vfio_main.c | 67 +++++++++++++++----
>> include/linux/vfio.h | 6 +-
>> 3 files changed, 66 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 <[email protected]>
>> +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/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
>> index bfa675d314ab..141f55c3faf5 100644
>> --- a/drivers/vfio/vfio_main.c
>> +++ b/drivers/vfio/vfio_main.c
>> @@ -46,6 +46,8 @@ 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 {
>> @@ -483,12 +485,13 @@ 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
>> @@ -498,7 +501,6 @@ 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
>> @@ -546,6 +548,13 @@ 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;
>> @@ -556,11 +565,15 @@ 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);
>> @@ -657,6 +670,7 @@ 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);
>> @@ -673,16 +687,21 @@ 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);
>>
>> @@ -692,6 +711,12 @@ 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)
>> group->dev_counter--;
>> 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);
>>
>> @@ -2145,6 +2173,7 @@ 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);
>> @@ -2160,12 +2189,20 @@ 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;
>>
>> @@ -2181,9 +2218,12 @@ 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;
>> }
>> @@ -2195,8 +2235,11 @@ 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 f03447c8774d..5c13f74da1bb 100644
>> --- a/include/linux/vfio.h
>> +++ b/include/linux/vfio.h
>> @@ -45,7 +45,8 @@ 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;
> I am not totally clear about remaining 'struct device *dev;' in
> vfio_device struct. I see it used in some places. Is it supposed to
> disappear at some point?
no, Eric. *dev will not disappear, it stores the dev pointet passed in by
caller of vfio_init_device().
>> @@ -154,10 +155,9 @@ 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);
>
> Thanks
>
> Eric
>
--
Regards,
Yi Liu
On 9/8/22 11:17, Yi Liu wrote:
> On 2022/9/8 17:06, Eric Auger wrote:
>> Hi Kevin,
>>
>> On 9/1/22 16:37, Kevin Tian wrote:
>>> From: Yi Liu <[email protected]>
>>>
>>> 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 <[email protected]>
>>> Signed-off-by: Yi Liu <[email protected]>
>>> Signed-off-by: Kevin Tian <[email protected]>
>>> Reviewed-by: Jason Gunthorpe <[email protected]>
>>> ---
>>> .../ABI/testing/sysfs-devices-vfio-dev | 8 +++
>>> drivers/vfio/vfio_main.c | 67
>>> +++++++++++++++----
>>> include/linux/vfio.h | 6 +-
>>> 3 files changed, 66 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 <[email protected]>
>>> +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/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
>>> index bfa675d314ab..141f55c3faf5 100644
>>> --- a/drivers/vfio/vfio_main.c
>>> +++ b/drivers/vfio/vfio_main.c
>>> @@ -46,6 +46,8 @@ 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 {
>>> @@ -483,12 +485,13 @@ 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
>>> @@ -498,7 +501,6 @@ 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
>>> @@ -546,6 +548,13 @@ 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;
>>> @@ -556,11 +565,15 @@ 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);
>>> @@ -657,6 +670,7 @@ 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);
>>> @@ -673,16 +687,21 @@ 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);
>>> @@ -692,6 +711,12 @@ 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)
>>> group->dev_counter--;
>>> 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);
>>> @@ -2145,6 +2173,7 @@ 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);
>>> @@ -2160,12 +2189,20 @@ 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;
>>> @@ -2181,9 +2218,12 @@ 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;
>>> }
>>> @@ -2195,8 +2235,11 @@ 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 f03447c8774d..5c13f74da1bb 100644
>>> --- a/include/linux/vfio.h
>>> +++ b/include/linux/vfio.h
>>> @@ -45,7 +45,8 @@ 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;
>> I am not totally clear about remaining 'struct device *dev;' in
>> vfio_device struct. I see it used in some places. Is it supposed to
>> disappear at some point?
>
> no, Eric. *dev will not disappear, it stores the dev pointet passed in by
> caller of vfio_init_device().
yeah I see but you have device->device.parent = device->dev;
Eric
>
>>> @@ -154,10 +155,9 @@ 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);
>>
>> Thanks
>>
>> Eric
>>
>
On Thu, Sep 08, 2022 at 11:39:07AM +0200, Eric Auger wrote:
> >> I am not totally clear about remaining 'struct device *dev;' in
> >> vfio_device struct. I see it used in some places. Is it supposed to
> >> disappear at some point?
> >
> > no, Eric. *dev will not disappear, it stores the dev pointet passed in by
> > caller of vfio_init_device().
>
> yeah I see but you have device->device.parent = device->dev;
IIRC we have a number of these redundancies now, often the drivers
store another copy of the dev too.
A significant use of dev is for printing things, what should be done
here is to create a subsystem wide vfio_warn/etc that takes in the
vfio_device, and then print properly from there. Now that we have a
struct device all the prints should also include the VFIO struct
device name, and then the PCI device perhaps in brackets.
Jason
> From: Jason Gunthorpe
> Sent: Thursday, September 8, 2022 8:37 PM
>
> On Thu, Sep 08, 2022 at 11:39:07AM +0200, Eric Auger wrote:
>
> > >> I am not totally clear about remaining 'struct device *dev;' in
> > >> vfio_device struct. I see it used in some places. Is it supposed to
> > >> disappear at some point?
> > >
> > > no, Eric. *dev will not disappear, it stores the dev pointet passed in by
> > > caller of vfio_init_device().
> >
> > yeah I see but you have device->device.parent = device->dev;
>
> IIRC we have a number of these redundancies now, often the drivers
> store another copy of the dev too.
>
> A significant use of dev is for printing things, what should be done
> here is to create a subsystem wide vfio_warn/etc that takes in the
> vfio_device, and then print properly from there. Now that we have a
> struct device all the prints should also include the VFIO struct
> device name, and then the PCI device perhaps in brackets.
>
Let me handle it in a separate patch (after this series).