diff options
Diffstat (limited to 'drivers/vfio/vfio.c')
| -rw-r--r-- | drivers/vfio/vfio.c | 117 |
1 files changed, 90 insertions, 27 deletions
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index fcc12f3e60a..6d78736563d 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -24,8 +24,10 @@ #include <linux/list.h> #include <linux/module.h> #include <linux/mutex.h> +#include <linux/rwsem.h> #include <linux/sched.h> #include <linux/slab.h> +#include <linux/stat.h> #include <linux/string.h> #include <linux/uaccess.h> #include <linux/vfio.h> @@ -57,7 +59,7 @@ struct vfio_iommu_driver { struct vfio_container { struct kref kref; struct list_head group_list; - struct mutex group_lock; + struct rw_semaphore group_lock; struct vfio_iommu_driver *iommu_driver; void *iommu_data; }; @@ -392,12 +394,13 @@ static void vfio_device_release(struct kref *kref) } /* Device reference always implies a group reference */ -static void vfio_device_put(struct vfio_device *device) +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); } +EXPORT_SYMBOL_GPL(vfio_device_put); static void vfio_device_get(struct vfio_device *device) { @@ -627,6 +630,33 @@ int vfio_add_group_dev(struct device *dev, } EXPORT_SYMBOL_GPL(vfio_add_group_dev); +/** + * Get a reference to the vfio_device for a device that is known to + * be bound to a vfio driver. The driver implicitly holds a + * vfio_device reference between vfio_add_group_dev and + * vfio_del_group_dev. We can therefore use drvdata to increment + * that reference from the struct device. This additional + * reference must be released by calling vfio_device_put. + */ +struct vfio_device *vfio_device_get_from_dev(struct device *dev) +{ + struct vfio_device *device = dev_get_drvdata(dev); + + vfio_device_get(device); + + return device; +} +EXPORT_SYMBOL_GPL(vfio_device_get_from_dev); + +/* + * 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); + /* Given a referenced group, check if it contains the device */ static bool vfio_dev_present(struct vfio_group *group, struct device *dev) { @@ -675,9 +705,13 @@ EXPORT_SYMBOL_GPL(vfio_del_group_dev); static long vfio_ioctl_check_extension(struct vfio_container *container, unsigned long arg) { - struct vfio_iommu_driver *driver = container->iommu_driver; + struct vfio_iommu_driver *driver; long ret = 0; + down_read(&container->group_lock); + + driver = container->iommu_driver; + switch (arg) { /* No base extensions yet */ default: @@ -707,10 +741,12 @@ static long vfio_ioctl_check_extension(struct vfio_container *container, VFIO_CHECK_EXTENSION, arg); } + up_read(&container->group_lock); + return ret; } -/* hold container->group_lock */ +/* hold write lock on container->group_lock */ static int __vfio_container_attach_groups(struct vfio_container *container, struct vfio_iommu_driver *driver, void *data) @@ -741,7 +777,7 @@ static long vfio_ioctl_set_iommu(struct vfio_container *container, struct vfio_iommu_driver *driver; long ret = -ENODEV; - mutex_lock(&container->group_lock); + down_write(&container->group_lock); /* * The container is designed to be an unprivileged interface while @@ -752,7 +788,7 @@ static long vfio_ioctl_set_iommu(struct vfio_container *container, * the container is deprivileged and returns to an unset state. */ if (list_empty(&container->group_list) || container->iommu_driver) { - mutex_unlock(&container->group_lock); + up_write(&container->group_lock); return -EINVAL; } @@ -799,7 +835,7 @@ static long vfio_ioctl_set_iommu(struct vfio_container *container, mutex_unlock(&vfio.iommu_drivers_lock); skip_drivers_unlock: - mutex_unlock(&container->group_lock); + up_write(&container->group_lock); return ret; } @@ -815,9 +851,6 @@ static long vfio_fops_unl_ioctl(struct file *filep, if (!container) return ret; - driver = container->iommu_driver; - data = container->iommu_data; - switch (cmd) { case VFIO_GET_API_VERSION: ret = VFIO_API_VERSION; @@ -829,8 +862,15 @@ static long vfio_fops_unl_ioctl(struct file *filep, ret = vfio_ioctl_set_iommu(container, arg); break; default: + down_read(&container->group_lock); + + driver = container->iommu_driver; + data = container->iommu_data; + if (driver) /* passthrough all unrecognized ioctls */ ret = driver->ops->ioctl(data, cmd, arg); + + up_read(&container->group_lock); } return ret; @@ -854,7 +894,7 @@ static int vfio_fops_open(struct inode *inode, struct file *filep) return -ENOMEM; INIT_LIST_HEAD(&container->group_list); - mutex_init(&container->group_lock); + init_rwsem(&container->group_lock); kref_init(&container->kref); filep->private_data = container; @@ -881,35 +921,55 @@ static ssize_t vfio_fops_read(struct file *filep, char __user *buf, size_t count, loff_t *ppos) { struct vfio_container *container = filep->private_data; - struct vfio_iommu_driver *driver = container->iommu_driver; + struct vfio_iommu_driver *driver; + ssize_t ret = -EINVAL; - if (unlikely(!driver || !driver->ops->read)) - return -EINVAL; + down_read(&container->group_lock); - return driver->ops->read(container->iommu_data, buf, count, ppos); + driver = container->iommu_driver; + if (likely(driver && driver->ops->read)) + ret = driver->ops->read(container->iommu_data, + buf, count, ppos); + + up_read(&container->group_lock); + + return ret; } static ssize_t vfio_fops_write(struct file *filep, const char __user *buf, size_t count, loff_t *ppos) { struct vfio_container *container = filep->private_data; - struct vfio_iommu_driver *driver = container->iommu_driver; + struct vfio_iommu_driver *driver; + ssize_t ret = -EINVAL; - if (unlikely(!driver || !driver->ops->write)) - return -EINVAL; + down_read(&container->group_lock); - return driver->ops->write(container->iommu_data, buf, count, ppos); + driver = container->iommu_driver; + if (likely(driver && driver->ops->write)) + ret = driver->ops->write(container->iommu_data, + buf, count, ppos); + + up_read(&container->group_lock); + + return ret; } static int vfio_fops_mmap(struct file *filep, struct vm_area_struct *vma) { struct vfio_container *container = filep->private_data; - struct vfio_iommu_driver *driver = container->iommu_driver; + struct vfio_iommu_driver *driver; + int ret = -EINVAL; - if (unlikely(!driver || !driver->ops->mmap)) - return -EINVAL; + down_read(&container->group_lock); - return driver->ops->mmap(container->iommu_data, vma); + driver = container->iommu_driver; + if (likely(driver && driver->ops->mmap)) + ret = driver->ops->mmap(container->iommu_data, vma); + + up_read(&container->group_lock); + + return ret; } static const struct file_operations vfio_fops = { @@ -933,7 +993,7 @@ static void __vfio_group_unset_container(struct vfio_group *group) struct vfio_container *container = group->container; struct vfio_iommu_driver *driver; - mutex_lock(&container->group_lock); + down_write(&container->group_lock); driver = container->iommu_driver; if (driver) @@ -951,7 +1011,7 @@ static void __vfio_group_unset_container(struct vfio_group *group) container->iommu_data = NULL; } - mutex_unlock(&container->group_lock); + up_write(&container->group_lock); vfio_container_put(container); } @@ -1011,7 +1071,7 @@ static int vfio_group_set_container(struct vfio_group *group, int container_fd) container = f.file->private_data; WARN_ON(!container); /* fget ensures we don't race vfio_release */ - mutex_lock(&container->group_lock); + down_write(&container->group_lock); driver = container->iommu_driver; if (driver) { @@ -1029,7 +1089,7 @@ static int vfio_group_set_container(struct vfio_group *group, int container_fd) atomic_inc(&group->container_users); unlock_out: - mutex_unlock(&container->group_lock); + up_write(&container->group_lock); fdput(f); return ret; } @@ -1300,6 +1360,9 @@ static const struct file_operations vfio_device_fops = { */ static char *vfio_devnode(struct device *dev, umode_t *mode) { + if (mode && (MINOR(dev->devt) == 0)) + *mode = S_IRUGO | S_IWUGO; + return kasprintf(GFP_KERNEL, "vfio/%s", dev_name(dev)); } |