diff options
Diffstat (limited to 'include/linux/virtio_config.h')
| -rw-r--r-- | include/linux/virtio_config.h | 83 |
1 files changed, 65 insertions, 18 deletions
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index 4d107ad31149..4b517649cfe8 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -23,8 +23,6 @@ struct virtio_shm_region { * any of @get/@set, @get_status/@set_status, or @get_features/ * @finalize_features are NOT safe to be called from an atomic * context. - * @enable_cbs: enable the callbacks - * vdev: the virtio_device * @get: read the value of a configuration field * vdev: the virtio_device * offset: the offset of the configuration field @@ -59,13 +57,19 @@ struct virtio_shm_region { * include a NULL entry for vqs unused by driver * Returns 0 on success or error status * @del_vqs: free virtqueues found by find_vqs(). + * @synchronize_cbs: synchronize with the virtqueue callbacks (optional) + * The function guarantees that all memory operations on the + * queue before it are visible to the vring_interrupt() that is + * called after it. + * vdev: the virtio_device * @get_features: get the array of feature bits for this device. * vdev: the virtio_device * Returns the first 64 feature bits (all we currently need). * @finalize_features: confirm what device features we'll be using. * vdev: the virtio_device - * This gives the final feature bits for the device: it can change + * This sends the driver feature bits to the device: it can change * the dev->feature bits if it wants. + * Note: despite the name this can be called any number of times. * Returns 0 on success or error status * @bus_name: return the bus name associated with the device (optional) * vdev: the virtio_device @@ -74,10 +78,21 @@ struct virtio_shm_region { * @set_vq_affinity: set the affinity for a virtqueue (optional). * @get_vq_affinity: get the affinity for a virtqueue (optional). * @get_shm_region: get a shared memory region based on the index. + * @disable_vq_and_reset: reset a queue individually (optional). + * vq: the virtqueue + * Returns 0 on success or error status + * disable_vq_and_reset will guarantee that the callbacks are disabled and + * synchronized. + * Except for the callback, the caller should guarantee that the vring is + * not accessed by any functions of virtqueue. + * @enable_vq_after_reset: enable a reset queue + * vq: the virtqueue + * Returns 0 on success or error status + * If disable_vq_and_reset is set, then enable_vq_after_reset must also be + * set. */ typedef void vq_callback_t(struct virtqueue *); struct virtio_config_ops { - void (*enable_cbs)(struct virtio_device *vdev); void (*get)(struct virtio_device *vdev, unsigned offset, void *buf, unsigned len); void (*set)(struct virtio_device *vdev, unsigned offset, @@ -91,6 +106,7 @@ struct virtio_config_ops { const char * const names[], const bool *ctx, struct irq_affinity *desc); void (*del_vqs)(struct virtio_device *); + void (*synchronize_cbs)(struct virtio_device *); u64 (*get_features)(struct virtio_device *vdev); int (*finalize_features)(struct virtio_device *vdev); const char *(*bus_name)(struct virtio_device *vdev); @@ -100,6 +116,8 @@ struct virtio_config_ops { int index); bool (*get_shm_region)(struct virtio_device *vdev, struct virtio_shm_region *region, u8 id); + int (*disable_vq_and_reset)(struct virtqueue *vq); + int (*enable_vq_after_reset)(struct virtqueue *vq); }; /* If driver didn't advertise the feature, it will never appear. */ @@ -220,8 +238,27 @@ int virtio_find_vqs_ctx(struct virtio_device *vdev, unsigned nvqs, } /** + * virtio_synchronize_cbs - synchronize with virtqueue callbacks + * @dev: the virtio device + */ +static inline +void virtio_synchronize_cbs(struct virtio_device *dev) +{ + if (dev->config->synchronize_cbs) { + dev->config->synchronize_cbs(dev); + } else { + /* + * A best effort fallback to synchronize with + * interrupts, preemption and softirq disabled + * regions. See comment above synchronize_rcu(). + */ + synchronize_rcu(); + } +} + +/** * virtio_device_ready - enable vq use in probe function - * @vdev: the device + * @dev: the virtio device * * Driver must call this to use vqs in the probe function. * @@ -232,10 +269,29 @@ void virtio_device_ready(struct virtio_device *dev) { unsigned status = dev->config->get_status(dev); - if (dev->config->enable_cbs) - dev->config->enable_cbs(dev); + WARN_ON(status & VIRTIO_CONFIG_S_DRIVER_OK); - BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK); +#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION + /* + * The virtio_synchronize_cbs() makes sure vring_interrupt() + * will see the driver specific setup if it sees vq->broken + * as false (even if the notifications come before DRIVER_OK). + */ + virtio_synchronize_cbs(dev); + __virtio_unbreak_device(dev); +#endif + /* + * The transport should ensure the visibility of vq->broken + * before setting DRIVER_OK. See the comments for the transport + * specific set_status() method. + * + * A well behaved device will only notify a virtqueue after + * DRIVER_OK, this means the device should "see" the coherenct + * memory write that set vq->broken as false which is done by + * the driver when it sees DRIVER_OK, then the following + * driver's vring_interrupt() will see vq->broken as false so + * we won't lose any notification. + */ dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK); } @@ -250,7 +306,7 @@ const char *virtio_bus_name(struct virtio_device *vdev) /** * virtqueue_set_affinity - setting affinity for a virtqueue * @vq: the virtqueue - * @cpu: the cpu no. + * @cpu_mask: the cpu mask * * Pay attention the function are best-effort: the affinity hint may not be set * due to config support, irq type and sharing. @@ -564,13 +620,4 @@ static inline void virtio_cwrite64(struct virtio_device *vdev, _r; \ }) -#ifdef CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS -int arch_has_restricted_virtio_memory_access(void); -#else -static inline int arch_has_restricted_virtio_memory_access(void) -{ - return 0; -} -#endif /* CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS */ - #endif /* _LINUX_VIRTIO_CONFIG_H */ |