Re: vhost question

[Stefan Hajnoczi <stefanha@gmail.com>]

On Thu, Mar 22, 2012 at 1:48 AM, Steve Glass <stevie.glass@gmail.com> wrote:
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> Just some further information concerning my earlier question
> concerning vhost and virtio.
>
> I'm using virtio to implement an emulated mac80211 device in the
> guest. A simple network simulation will be used to control delivery of
> frames between guests and for this I am using the vhost approach.
>
> A simple first-cut attempt at the tx and rx kick handlers are given
> below. When the guest transmits frames the vhost's TX kick handler is
> executed and copies the buffers onto a queue for the intended
> recipient(s). When the vhost's RX kick handler is run it copies the
> buffer from the queue and notifies the client that the buffers have
> been used.
>
> The problem is that if there are no frames in the queue when the guest
> rx kick handler runs then it has to exit and I have to arrange that it
> runs again. That's done in the current prototype by having the guests
> poll using a timer - which is ugly and inefficient. Can I get the
> vhost tx kick handler to wake the appropriate vhost rx kick handler?
> How can I achieve this?

Can you queue a tx->rx kick on the vhost work queue with vhost_work_queue()?

Stefan