lguest: publish last_avail_idx. Set the VIRTIO_RING_F_PUBLISH_INDICES feature on all devices, and use the last_avail within the vring rather than storing our own. Signed-off-by: Rusty Russell --- Documentation/lguest/lguest.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff -r ef75a80d3284 Documentation/lguest/lguest.c --- a/Documentation/lguest/lguest.c Tue Jul 22 18:01:55 2008 +1000 +++ b/Documentation/lguest/lguest.c Tue Jul 22 18:02:41 2008 +1000 @@ -157,9 +157,6 @@ struct virtqueue /* The actual ring of buffers. */ struct vring vring; - /* Last available index we saw. */ - u16 last_avail_idx; - /* The routine to call when the Guest pings us, or timeout. */ void (*handle_output)(int fd, struct virtqueue *me, bool timeout); @@ -201,7 +198,7 @@ static void *_convert(struct iovec *iov, } /* Wrapper for the last available index. Makes it easier to change. */ -#define lg_last_avail(vq) ((vq)->last_avail_idx) +#define lg_last_avail(vq) vring_last_avail(&(vq)->vring) /* The virtio configuration space is defined to be little-endian. x86 is * little-endian too, but it's nice to be explicit so we have these helpers. */ @@ -1237,7 +1234,6 @@ static void add_virtqueue(struct device /* Initialize the virtqueue */ vq->next = NULL; - vq->last_avail_idx = 0; vq->dev = dev; vq->inflight = 0; vq->blocked = false; @@ -1295,6 +1291,10 @@ static void add_feature(struct device *d * how we use it. */ static void set_config(struct device *dev, unsigned len, const void *conf) { + /* We always set the VIRTIO_RING_F_PUBLISH_INDICES feature + * bit, so now is a good time to do that. */ + add_feature(dev, VIRTIO_RING_F_PUBLISH_INDICES); + /* Check we haven't overflowed our single page. */ if (device_config(dev) + len > devices.descpage + getpagesize()) errx(1, "Too many devices"); @@ -1369,6 +1369,8 @@ static void setup_console(void) add_virtqueue(dev, VIRTQUEUE_NUM, enable_fd); add_virtqueue(dev, VIRTQUEUE_NUM, handle_console_output); + /* Every device should set this bit. */ + add_feature(dev, VIRTIO_RING_F_PUBLISH_INDICES); verbose("device %u: console\n", devices.device_num++); } /*:*/