diff options
author | Maxime Ripard <maxime@cerno.tech> | 2021-05-11 13:35:52 +0200 |
---|---|---|
committer | Maxime Ripard <maxime@cerno.tech> | 2021-05-11 13:35:52 +0200 |
commit | c55b44c9386f3ee1b08752638559f19deaf6040d (patch) | |
tree | c843a21f45180387fcd9eb2625cc9d1f166a3156 /drivers/vfio/vfio.c | |
parent | MAINTAINERS: Update my e-mail (diff) | |
parent | Linux 5.13-rc1 (diff) | |
download | linux-c55b44c9386f3ee1b08752638559f19deaf6040d.tar.xz linux-c55b44c9386f3ee1b08752638559f19deaf6040d.zip |
Merge drm/drm-fixes into drm-misc-fixes
Start this new release drm-misc-fixes branch
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Diffstat (limited to 'drivers/vfio/vfio.c')
-rw-r--r-- | drivers/vfio/vfio.c | 210 |
1 files changed, 62 insertions, 148 deletions
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 38779e6fd80c..5e631c359ef2 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -46,7 +46,6 @@ static struct vfio { struct mutex group_lock; struct cdev group_cdev; dev_t group_devt; - wait_queue_head_t release_q; } vfio; struct vfio_iommu_driver { @@ -90,15 +89,6 @@ struct vfio_group { struct blocking_notifier_head notifier; }; -struct vfio_device { - struct kref kref; - struct device *dev; - const struct vfio_device_ops *ops; - struct vfio_group *group; - struct list_head group_next; - void *device_data; -}; - #ifdef CONFIG_VFIO_NOIOMMU static bool noiommu __read_mostly; module_param_named(enable_unsafe_noiommu_mode, @@ -109,8 +99,8 @@ MODULE_PARM_DESC(enable_unsafe_noiommu_mode, "Enable UNSAFE, no-IOMMU mode. Thi /* * vfio_iommu_group_{get,put} are only intended for VFIO bus driver probe * and remove functions, any use cases other than acquiring the first - * reference for the purpose of calling vfio_add_group_dev() or removing - * that symmetric reference after vfio_del_group_dev() should use the raw + * reference for the purpose of calling vfio_register_group_dev() or removing + * that symmetric reference after vfio_unregister_group_dev() should use the raw * iommu_group_{get,put} functions. In particular, vfio_iommu_group_put() * removes the device from the dummy group and cannot be nested. */ @@ -532,67 +522,17 @@ static struct vfio_group *vfio_group_get_from_dev(struct device *dev) /** * Device objects - create, release, get, put, search */ -static -struct vfio_device *vfio_group_create_device(struct vfio_group *group, - struct device *dev, - const struct vfio_device_ops *ops, - void *device_data) -{ - struct vfio_device *device; - - device = kzalloc(sizeof(*device), GFP_KERNEL); - if (!device) - return ERR_PTR(-ENOMEM); - - kref_init(&device->kref); - device->dev = dev; - device->group = group; - device->ops = ops; - device->device_data = device_data; - dev_set_drvdata(dev, device); - - /* No need to get group_lock, caller has group reference */ - vfio_group_get(group); - - mutex_lock(&group->device_lock); - list_add(&device->group_next, &group->device_list); - group->dev_counter++; - mutex_unlock(&group->device_lock); - - return device; -} - -static void vfio_device_release(struct kref *kref) -{ - struct vfio_device *device = container_of(kref, - struct vfio_device, kref); - struct vfio_group *group = device->group; - - list_del(&device->group_next); - group->dev_counter--; - mutex_unlock(&group->device_lock); - - dev_set_drvdata(device->dev, NULL); - - kfree(device); - - /* vfio_del_group_dev may be waiting for this device */ - wake_up(&vfio.release_q); -} - /* Device reference always implies a group reference */ void vfio_device_put(struct vfio_device *device) { - struct vfio_group *group = device->group; - kref_put_mutex(&device->kref, vfio_device_release, &group->device_lock); - vfio_group_put(group); + if (refcount_dec_and_test(&device->refcount)) + complete(&device->comp); } EXPORT_SYMBOL_GPL(vfio_device_put); -static void vfio_device_get(struct vfio_device *device) +static bool vfio_device_try_get(struct vfio_device *device) { - vfio_group_get(device->group); - kref_get(&device->kref); + return refcount_inc_not_zero(&device->refcount); } static struct vfio_device *vfio_group_get_device(struct vfio_group *group, @@ -602,8 +542,7 @@ static struct vfio_device *vfio_group_get_device(struct vfio_group *group, mutex_lock(&group->device_lock); list_for_each_entry(device, &group->device_list, group_next) { - if (device->dev == dev) { - vfio_device_get(device); + if (device->dev == dev && vfio_device_try_get(device)) { mutex_unlock(&group->device_lock); return device; } @@ -801,14 +740,22 @@ static int vfio_iommu_group_notifier(struct notifier_block *nb, /** * VFIO driver API */ -int vfio_add_group_dev(struct device *dev, - const struct vfio_device_ops *ops, void *device_data) +void vfio_init_group_dev(struct vfio_device *device, struct device *dev, + const struct vfio_device_ops *ops) +{ + init_completion(&device->comp); + device->dev = dev; + device->ops = ops; +} +EXPORT_SYMBOL_GPL(vfio_init_group_dev); + +int vfio_register_group_dev(struct vfio_device *device) { + struct vfio_device *existing_device; struct iommu_group *iommu_group; struct vfio_group *group; - struct vfio_device *device; - iommu_group = iommu_group_get(dev); + iommu_group = iommu_group_get(device->dev); if (!iommu_group) return -EINVAL; @@ -827,31 +774,29 @@ int vfio_add_group_dev(struct device *dev, iommu_group_put(iommu_group); } - device = vfio_group_get_device(group, dev); - if (device) { - dev_WARN(dev, "Device already exists on group %d\n", + existing_device = vfio_group_get_device(group, device->dev); + if (existing_device) { + dev_WARN(device->dev, "Device already exists on group %d\n", iommu_group_id(iommu_group)); - vfio_device_put(device); + vfio_device_put(existing_device); vfio_group_put(group); return -EBUSY; } - device = vfio_group_create_device(group, dev, ops, device_data); - if (IS_ERR(device)) { - vfio_group_put(group); - return PTR_ERR(device); - } + /* Our reference on group is moved to the device */ + device->group = group; - /* - * Drop all but the vfio_device reference. The vfio_device holds - * a reference to the vfio_group, which holds a reference to the - * iommu_group. - */ - vfio_group_put(group); + /* Refcounting can't start until the driver calls register */ + refcount_set(&device->refcount, 1); + + mutex_lock(&group->device_lock); + list_add(&device->group_next, &group->device_list); + group->dev_counter++; + mutex_unlock(&group->device_lock); return 0; } -EXPORT_SYMBOL_GPL(vfio_add_group_dev); +EXPORT_SYMBOL_GPL(vfio_register_group_dev); /** * Get a reference to the vfio_device for a device. Even if the @@ -886,7 +831,7 @@ static struct vfio_device *vfio_device_get_from_name(struct vfio_group *group, int ret; if (it->ops->match) { - ret = it->ops->match(it->device_data, buf); + ret = it->ops->match(it, buf); if (ret < 0) { device = ERR_PTR(ret); break; @@ -895,9 +840,8 @@ static struct vfio_device *vfio_device_get_from_name(struct vfio_group *group, ret = !strcmp(dev_name(it->dev), buf); } - if (ret) { + if (ret && vfio_device_try_get(it)) { device = it; - vfio_device_get(device); break; } } @@ -907,32 +851,15 @@ static struct vfio_device *vfio_device_get_from_name(struct vfio_group *group, } /* - * Caller must hold a reference to the vfio_device - */ -void *vfio_device_data(struct vfio_device *device) -{ - return device->device_data; -} -EXPORT_SYMBOL_GPL(vfio_device_data); - -/* * Decrement the device reference count and wait for the device to be * removed. Open file descriptors for the device... */ -void *vfio_del_group_dev(struct device *dev) +void vfio_unregister_group_dev(struct vfio_device *device) { - DEFINE_WAIT_FUNC(wait, woken_wake_function); - struct vfio_device *device = dev_get_drvdata(dev); struct vfio_group *group = device->group; - void *device_data = device->device_data; struct vfio_unbound_dev *unbound; unsigned int i = 0; bool interrupted = false; - - /* - * The group exists so long as we have a device reference. Get - * a group reference and use it to scan for the device going away. - */ - vfio_group_get(group); + long rc; /* * When the device is removed from the group, the group suddenly @@ -945,7 +872,7 @@ void *vfio_del_group_dev(struct device *dev) */ unbound = kzalloc(sizeof(*unbound), GFP_KERNEL); if (unbound) { - unbound->dev = dev; + unbound->dev = device->dev; mutex_lock(&group->unbound_lock); list_add(&unbound->unbound_next, &group->unbound_list); mutex_unlock(&group->unbound_lock); @@ -953,44 +880,33 @@ void *vfio_del_group_dev(struct device *dev) WARN_ON(!unbound); vfio_device_put(device); - - /* - * If the device is still present in the group after the above - * 'put', then it is in use and we need to request it from the - * bus driver. The driver may in turn need to request the - * device from the user. We send the request on an arbitrary - * interval with counter to allow the driver to take escalating - * measures to release the device if it has the ability to do so. - */ - add_wait_queue(&vfio.release_q, &wait); - - do { - device = vfio_group_get_device(group, dev); - if (!device) - break; - + rc = try_wait_for_completion(&device->comp); + while (rc <= 0) { if (device->ops->request) - device->ops->request(device_data, i++); - - vfio_device_put(device); + device->ops->request(device, i++); if (interrupted) { - wait_woken(&wait, TASK_UNINTERRUPTIBLE, HZ * 10); + rc = wait_for_completion_timeout(&device->comp, + HZ * 10); } else { - wait_woken(&wait, TASK_INTERRUPTIBLE, HZ * 10); - if (signal_pending(current)) { + rc = wait_for_completion_interruptible_timeout( + &device->comp, HZ * 10); + if (rc < 0) { interrupted = true; - dev_warn(dev, + dev_warn(device->dev, "Device is currently in use, task" " \"%s\" (%d) " "blocked until device is released", current->comm, task_pid_nr(current)); } } + } - } while (1); + mutex_lock(&group->device_lock); + list_del(&device->group_next); + group->dev_counter--; + mutex_unlock(&group->device_lock); - remove_wait_queue(&vfio.release_q, &wait); /* * In order to support multiple devices per group, devices can be * plucked from the group while other devices in the group are still @@ -1008,11 +924,10 @@ void *vfio_del_group_dev(struct device *dev) if (list_empty(&group->device_list)) wait_event(group->container_q, !group->container); + /* Matches the get in vfio_register_group_dev() */ vfio_group_put(group); - - return device_data; } -EXPORT_SYMBOL_GPL(vfio_del_group_dev); +EXPORT_SYMBOL_GPL(vfio_unregister_group_dev); /** * VFIO base fd, /dev/vfio/vfio @@ -1454,7 +1369,7 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) if (IS_ERR(device)) return PTR_ERR(device); - ret = device->ops->open(device->device_data); + ret = device->ops->open(device); if (ret) { vfio_device_put(device); return ret; @@ -1466,7 +1381,7 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) */ ret = get_unused_fd_flags(O_CLOEXEC); if (ret < 0) { - device->ops->release(device->device_data); + device->ops->release(device); vfio_device_put(device); return ret; } @@ -1476,7 +1391,7 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) if (IS_ERR(filep)) { put_unused_fd(ret); ret = PTR_ERR(filep); - device->ops->release(device->device_data); + device->ops->release(device); vfio_device_put(device); return ret; } @@ -1633,7 +1548,7 @@ static int vfio_device_fops_release(struct inode *inode, struct file *filep) { struct vfio_device *device = filep->private_data; - device->ops->release(device->device_data); + device->ops->release(device); vfio_group_try_dissolve_container(device->group); @@ -1650,7 +1565,7 @@ static long vfio_device_fops_unl_ioctl(struct file *filep, if (unlikely(!device->ops->ioctl)) return -EINVAL; - return device->ops->ioctl(device->device_data, cmd, arg); + return device->ops->ioctl(device, cmd, arg); } static ssize_t vfio_device_fops_read(struct file *filep, char __user *buf, @@ -1661,7 +1576,7 @@ static ssize_t vfio_device_fops_read(struct file *filep, char __user *buf, if (unlikely(!device->ops->read)) return -EINVAL; - return device->ops->read(device->device_data, buf, count, ppos); + return device->ops->read(device, buf, count, ppos); } static ssize_t vfio_device_fops_write(struct file *filep, @@ -1673,7 +1588,7 @@ static ssize_t vfio_device_fops_write(struct file *filep, if (unlikely(!device->ops->write)) return -EINVAL; - return device->ops->write(device->device_data, buf, count, ppos); + return device->ops->write(device, buf, count, ppos); } static int vfio_device_fops_mmap(struct file *filep, struct vm_area_struct *vma) @@ -1683,7 +1598,7 @@ static int vfio_device_fops_mmap(struct file *filep, struct vm_area_struct *vma) if (unlikely(!device->ops->mmap)) return -EINVAL; - return device->ops->mmap(device->device_data, vma); + return device->ops->mmap(device, vma); } static const struct file_operations vfio_device_fops = { @@ -2379,7 +2294,6 @@ static int __init vfio_init(void) mutex_init(&vfio.iommu_drivers_lock); INIT_LIST_HEAD(&vfio.group_list); INIT_LIST_HEAD(&vfio.iommu_drivers_list); - init_waitqueue_head(&vfio.release_q); ret = misc_register(&vfio_dev); if (ret) { |