Stefan Hajnoczi <stefanha@xxxxxxxxx> writes: > On Thu, May 30, 2013 at 7:23 AM, Rusty Russell <rusty@xxxxxxxxxxxxxxx> wrote: >> Anthony Liguori <anthony@xxxxxxxxxxxxx> writes: >>> Rusty Russell <rusty@xxxxxxxxxxxxxxx> writes: >>>> On Fri, May 24, 2013 at 08:47:58AM -0500, Anthony Liguori wrote: >>>>> FWIW, I think what's more interesting is using vhost-net as a networking >>>>> backend with virtio-net in QEMU being what's guest facing. >>>>> >>>>> In theory, this gives you the best of both worlds: QEMU acts as a first >>>>> line of defense against a malicious guest while still getting the >>>>> performance advantages of vhost-net (zero-copy). >>>>> >>>> It would be an interesting idea if we didn't already have the vhost >>>> model where we don't need the userspace bounce. >>> >>> The model is very interesting for QEMU because then we can use vhost as >>> a backend for other types of network adapters (like vmxnet3 or even >>> e1000). >>> >>> It also helps for things like fault tolerance where we need to be able >>> to control packet flow within QEMU. >> >> (CC's reduced, context added, Dmitry Fleytman added for vmxnet3 thoughts). >> >> Then I'm really confused as to what this would look like. A zero copy >> sendmsg? We should be able to implement that today. >> >> On the receive side, what can we do better than readv? If we need to >> return to userspace to tell the guest that we've got a new packet, we >> don't win on latency. We might reduce syscall overhead with a >> multi-dimensional readv to read multiple packets at once? > > Sounds like recvmmsg(2). Could we map this to mergable rx buffers though? Regards, Anthony Liguori > > Stefan -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
