hw/virtio/vhost.h

4 #include "net/vhost_net.h"
5 #include "hw/virtio/vhost-backend.h"
14 /* Generic structures common for any vhost based device. */
67     /* Vhost device config space changed callback
75  * struct vhost_dev - common vhost_dev structure
90     /* the first virtqueue which would be used by this vhost dev */
92     /* one past the last vq index for the virtio device (not vhost) */
94     /* if non-zero, minimum required value for max_queues */
97      * vhost feature handling requires matching the feature set
102      * @acked_features: final negotiated features with front-end driver
115      * @protocol_features: is the vhost-user only feature set by
124     /* @started: is the vhost device started? */
155  * vhost_dev_init() - initialise the vhost interface
157  * @opaque: opaque ptr passed to backend (vhost/vhost-user/vdpa)
162  * The initialisation of the vhost device will trigger the
167  * Return: 0 on success, non-zero on error while setting errp.
174  * vhost_dev_cleanup() - tear down and cleanup vhost interface
184  * vhost_dev_enable_notifiers() - enable event notifiers
188  * Enable notifications directly to the vhost device rather than being
190  * the vhost device is started via @vhost_dev_start.
197  * vhost_dev_disable_notifiers - disable event notifications
201  * Disable direct notifications to vhost device.
208  * vhost_dev_is_started() - report status of vhost device
211  * Return the started status of the vhost device
215     return hdev->started;  in vhost_dev_is_started()
219  * vhost_dev_start() - start the vhost device
224  * Starts the vhost device. From this point VirtIO feature negotiation
232  * vhost_dev_stop() - stop the vhost device
237  * Stop the vhost device. After the device is stopped the notifiers
246  * vhost_dev_force_stop() - force stop the vhost device
251  * Force stop the vhost device. After the device is stopped the notifiers
254  * attempt to flush in-flight backend requests by skipping GET_VRING_BASE
261  * DOC: vhost device configuration handling
266  * change the configuration over time the vhost handler should
274  * vhost_dev_get_config() - fetch device configuration
285  * vhost_dev_set_config() - set device configuration
296  * Return: 0 on success, non-zero on error
302  * vhost_dev_set_config_notifier() - register VhostDevConfigOps
324  * vhost_get_features() - return a sanitised set of feature bits
330  * is supported by the vhost backend (hdev->features), the supported
337  * vhost_ack_features() - set vhost acked_features
342  * This sets the internal hdev->acked_features to the intersection of
375     return -ENOSYS;  in vhost_reset_device()
380  * vhost_supports_device_state(): Checks whether the back-end supports
385  * @dev: The vhost device
401  * the back-end for the purpose of migration.  Data is to be transferred
405  * must take this as the end-of-transfer signal and close its FD, too.
407  * @fd is the back-end's end of the pipe: The write FD for SAVE, and the
409  * back-end, i.e. closes it in the front-end.
411  * The back-end may optionally reply with an FD of its own, if this
413  * stored in *reply_fd.  The back-end will discard the FD sent to it,
414  * and the front-end must use *reply_fd for transferring state to/from
415  * the back-end.
417  * @dev: The vhost device
420  *             from the back-end and stored by the front-end in the
423  *             by the front-end from the migration stream and sent to
424  *             the back-end to restore the saved state.
428  * @fd: Back-end's end of the pipe through which to transfer state; note
429  *      that ownership is transferred to the back-end, so this function
430  *      closes @fd in the front-end.
431  * @reply_fd: If the back-end wishes to use a different pipe for state
432  *            transfer, this will contain an FD for the front-end to
433  *            use.  Otherwise, -1 is stored here.
436  * Returns 0 on success, and -errno on failure.
447  * back-end via vhost_set_device_state_fd(), i.e. once the sending end
448  * has closed the pipe, inquire the back-end to report any potential
451  * - During outgoing migration, when the source side had already started
453  * - During incoming migration, when the received state is somehow
454  *   invalid and cannot be processed by the back-end
456  * @dev: The vhost device
459  * Returns 0 when the back-end reports successful state transfer and
460  * processing, and -errno when an error occurred somewhere.
465  * vhost_save_backend_state(): High-level function to receive a vhost
466  * back-end's state, and save it in @f.  Uses
467  * `vhost_set_device_state_fd()` to get the data from the back-end, and
469  * respective length (be32).  The end is marked by a 0-length chunk.
474  * @dev: The vhost device from which to save the state
478  * Returns 0 on success, and -errno otherwise.
486     return -ENOSYS;  in vhost_save_backend_state()
491  * vhost_load_backend_state(): High-level function to load a vhost
492  * back-end's state from @f, and send it over to the back-end.  Reads
494  * `vhost_set_device_state_fd()` to transfer it to the back-end.
499  * @dev: The vhost device to which to send the state
503  * Returns 0 on success, and -errno otherwise.
511     return -ENOSYS;  in vhost_load_backend_state()