On Thu, Jan 13, 2022 at 10:19:46AM -0500, Michael S. Tsirkin wrote:
On Thu, Jan 13, 2022 at 03:56:42PM +0100, Stefano Garzarella wrote:
In vhost_enable_notify() we enable the notifications and we read
the avail index to check if new buffers have become available in
the meantime. In this case, the device would go to re-read avail
index to access the descriptor.
As we already do in other place, we can cache the value in `avail_idx`
and compare it with `last_avail_idx` to check if there are new
buffers available.
Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
I guess we can ... but what's the point?
That without this patch if avail index is new, then device when will
call vhost_get_vq_desc() will find old value in cache and will read it
again.
With this patch we also do the same path and update the cache every time
we read avail index.
I marked it RFC because I don't know if it's worth it :-)
Stefano
