| Message ID | 20220921104401.38898-16-kevin.tian@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Tidy up vfio_device life cycle | expand |
Hi Kevin, This introduced the regression discovered here: https://lore.kernel.org/all/20220928125650.0a2ea297.alex.williamson@redhat.com/ Seems we're not releasing the resources when removing an mdev. This is a regression, so it needs to be fixed or reverted before the merge window. Thanks, Alex On Wed, 21 Sep 2022 18:44:01 +0800 Kevin Tian <kevin.tian@intel.com> 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. > > 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 +++ > MAINTAINERS | 1 + > drivers/vfio/vfio_main.c | 64 +++++++++++++++---- > include/linux/vfio.h | 6 +- > 4 files changed, 65 insertions(+), 14 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/MAINTAINERS b/MAINTAINERS > index d30f26e07cd3..02c8f11b1c17 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -21312,6 +21312,7 @@ R: Cornelia Huck <cohuck@redhat.com> > L: kvm@vger.kernel.org > 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 c27449613a1d..f9d10dbcf3e6 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); > > /* > * Allocate 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); > @@ -2377,11 +2406,18 @@ 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; > > + /* /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"); > if (ret) > goto err_alloc_chrdev; > @@ -2398,9 +2434,12 @@ 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 +2451,11 @@ 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);
On Thu, Sep 29, 2022 at 10:55:19AM -0600, Alex Williamson wrote: > Hi Kevin, > > This introduced the regression discovered here: > > https://lore.kernel.org/all/20220928125650.0a2ea297.alex.williamson@redhat.com/ > > Seems we're not releasing the resources when removing an mdev. This is > a regression, so it needs to be fixed or reverted before the merge > window. Thanks, My guess at the fix for this: https://lore.kernel.org/r/0-v1-013609965fe8+9d-vfio_gvt_unregister_jgg@nvidia.com Jason
On Thu, 29 Sep 2022 14:49:56 -0300 Jason Gunthorpe <jgg@ziepe.ca> wrote: > On Thu, Sep 29, 2022 at 10:55:19AM -0600, Alex Williamson wrote: > > Hi Kevin, > > > > This introduced the regression discovered here: > > > > https://lore.kernel.org/all/20220928125650.0a2ea297.alex.williamson@redhat.com/ > > > > Seems we're not releasing the resources when removing an mdev. This is > > a regression, so it needs to be fixed or reverted before the merge > > window. Thanks, > > My guess at the fix for this: > > https://lore.kernel.org/r/0-v1-013609965fe8+9d-vfio_gvt_unregister_jgg@nvidia.com Indeed this seems to work I'll look for acks and further reviews from Intel folks. Thanks! Alex
> From: Alex Williamson <alex.williamson@redhat.com> > Sent: Friday, September 30, 2022 2:24 AM > > On Thu, 29 Sep 2022 14:49:56 -0300 > Jason Gunthorpe <jgg@ziepe.ca> wrote: > > > On Thu, Sep 29, 2022 at 10:55:19AM -0600, Alex Williamson wrote: > > > Hi Kevin, > > > > > > This introduced the regression discovered here: > > > > > > > https://lore.kernel.org/all/20220928125650.0a2ea297.alex.williamson@redh > at.com/ > > > > > > Seems we're not releasing the resources when removing an mdev. This is > > > a regression, so it needs to be fixed or reverted before the merge > > > window. Thanks, > > > > My guess at the fix for this: > > > > https://lore.kernel.org/r/0-v1-013609965fe8+9d- > vfio_gvt_unregister_jgg@nvidia.com > > Indeed this seems to work I'll look for acks and further reviews from > Intel folks. Thanks! > Thanks Jason for baking a quick fix! I've acked it.
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/MAINTAINERS b/MAINTAINERS index d30f26e07cd3..02c8f11b1c17 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -21312,6 +21312,7 @@ R: Cornelia Huck <cohuck@redhat.com> L: kvm@vger.kernel.org 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 c27449613a1d..f9d10dbcf3e6 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); /* * Allocate 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); @@ -2377,11 +2406,18 @@ 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; + /* /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"); if (ret) goto err_alloc_chrdev; @@ -2398,9 +2434,12 @@ 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 +2451,11 @@ 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);