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Commit 71e4b8bf authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by Rusty Russell
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virtio_rpmsg: set DRIVER_OK before using device 



virtio spec requires that all drivers set DRIVER_OK
before using devices. While rpmsg isn't yet
included in the virtio 1 spec, previous spec versions
also required this.

virtio rpmsg violates this rule: is calls kick
before setting DRIVER_OK.

The fix isn't trivial since simply calling virtio_device_ready earlier
would mean we might get an interrupt in parallel with adding buffers.

Instead, split kick out to prepare+notify calls.  prepare before
virtio_device_ready - when we know we won't get interrupts. notify right
afterwards.

Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Acked-by: default avatarOhad Ben-Cohen <ohad@wizery.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 8051a2a5

drivers/rpmsg/virtio_rpmsg_bus.c

+16 −1
Original line number Diff line number Diff line
@@ -951,6 +951,7 @@ static int rpmsg_probe(struct virtio_device *vdev) 
	void *bufs_va;

	int err = 0, i;

	size_t total_buf_space;

	bool notify;



	vrp = kzalloc(sizeof(*vrp), GFP_KERNEL);

	if (!vrp)
@@ -1030,8 +1031,22 @@ static int rpmsg_probe(struct virtio_device *vdev) 
		}

	}



	/*

	 * Prepare to kick but don't notify yet - we can't do this before

	 * device is ready.

	 */

	notify = virtqueue_kick_prepare(vrp->rvq);



	/* From this point on, we can notify and get callbacks. */

	virtio_device_ready(vdev);



	/* tell the remote processor it can start sending messages */

	virtqueue_kick(vrp->rvq);

	/*

	 * this might be concurrent with callbacks, but we are only

	 * doing notify, not a full kick here, so that's ok.

	 */

	if (notify)

		virtqueue_notify(vrp->rvq);



	dev_info(&vdev->dev, "rpmsg host is online\n");