Messages in this thread | | | Date | Thu, 8 Sep 2022 17:17:03 +0800 | Subject | Re: [PATCH v2 15/15] vfio: Add struct device to vfio_device | From | Yi Liu <> |
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On 2022/9/8 17:06, Eric Auger wrote: > Hi Kevin, > > On 9/1/22 16:37, Kevin Tian wrote: >> From: Yi Liu <yi.l.liu@intel.com> >> >> 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@nvidia.com> >> Signed-off-by: Yi Liu <yi.l.liu@intel.com> >> Signed-off-by: Kevin Tian <kevin.tian@intel.com> >> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> >> --- >> .../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 <yi.l.liu@intel.com> >> +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
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