From 6e5aa7efb27aec7e55b6463fa2c8db594c4226fa Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 4 Feb 2008 23:50:03 -0500 Subject: virtio: reset function A reset function solves three problems: 1) It allows us to renegotiate features, eg. if we want to upgrade a guest driver without rebooting the guest. 2) It gives us a clean way of shutting down virtqueues: after a reset, we know that the buffers won't be used by the host, and 3) It helps the guest recover from messed-up drivers. So we remove the ->shutdown hook, and the only way we now remove feature bits is via reset. We leave it to the driver to do the reset before it deletes queues: the balloon driver, for example, needs to chat to the host in its remove function. Signed-off-by: Rusty Russell --- include/linux/virtio_config.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/virtio_config.h') diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index 81f828ac8f4..d581b2914b3 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -43,6 +43,9 @@ struct virtio_device; * @set_status: write the status byte * vdev: the virtio_device * status: the new status byte + * @reset: reset the device + * vdev: the virtio device + * After this, status and feature negotiation must be done again * @find_vq: find a virtqueue and instantiate it. * vdev: the virtio_device * index: the 0-based virtqueue number in case there's more than one. @@ -59,6 +62,7 @@ struct virtio_config_ops const void *buf, unsigned len); u8 (*get_status)(struct virtio_device *vdev); void (*set_status)(struct virtio_device *vdev, u8 status); + void (*reset)(struct virtio_device *vdev); struct virtqueue *(*find_vq)(struct virtio_device *vdev, unsigned index, void (*callback)(struct virtqueue *)); -- cgit v1.2.3