Re: [PATCH] AF_VMCHANNEL address family for guest<->host communication.

Gleb Natapov
2008-12-16T06:57:27Z

On Tue, Dec 16, 2008 at 02:45:11AM +0300, Evgeniy Polyakov wrote:
> Hi Anthony.
>
> On Mon, Dec 15, 2008 at 05:01:14PM -0600, Anthony Liguori (anthony@codemonkey.ws) wrote:
> > Yes, and I went down the road of using a dedicated network device and
> > using raw ethernet as the protocol. The thing that killed that was the
> > fact that it's not reliable. You need something like TCP to add
> > reliability.
> >
> > But that's a lot of work and a bit backwards. Use a unreliable
> > transport but use TCP on top of it to get reliability. Our link
> > (virtio) is inherently reliable so why not just expose a reliable
> > interface to userspace?
>
> I removed original mail and did not check archive, but doesn't rx/tx
> queues of the virtio device have limited size? I do hope they have,
> which means that either your network drops packets or blocks.
>
It blocks.

> Another approach is to implement that virtio backend with netlink based
> userspace interface (like using connector or genetlink). This does not
> differ too much from what you have with special socket family, but at
> least it does not duplicate existing functionality of
> userspace-kernelspace communications.
>
I implemented vmchannel using connector initially (the downside is that
message can be dropped). Is this more expectable for upstream? The
implementation was 300 lines of code.

--
Gleb.