> From: Jason Wang [mailto:jasow...@redhat.com] > Sent: Tuesday, 28 March 2017 19:39 > > On 2017年03月29日 02:55, Andrew Baumann wrote: > >> From: Stefan Weil [mailto:s...@weilnetz.de] > >> Sent: Tuesday, 28 March 2017 11:28 > >> Am 25.03.2017 um 00:46 schrieb Andrew Baumann: > >>> The docs generally steer users away from using the legacy -net > >>> parameter, however on win32 attempting to enable a tap device using > >>> -netdev tap fails at an abort() in tap_enable(). Removing the abort()s > >>> seems to be enough to get everything working, so do that. > >>> > >>> Signed-off-by: Andrew Baumann <andrew.baum...@microsoft.com> [...] > >> Jason, what is the use of tap_enable, tap_disable? > > It should be only used when we want to enable and disable a specific > queue of a multiqueue supported tap. > > >> Is it fine > >> to simply do nothing on Windows here? > > Unless windows support multiqueue tap, we should keep the assert here. > > > I was also hoping for a review -- I'm no expert on this stuff either, but my > quick reading of those code paths is that they issue ioctls to enable/disable > packet reception on the underlying tap device. As win32 TAP is implemented, > that is already enabled from start of day. > > > > It's possible this patch still does not permit dynamic reconfiguration of > > tap > devices (e.g. from the monitor console). However, it does work with the - > netdev tap option on the command-line. > > > >> And is this something for QEMU 2.9 (I added question to subject line)? > > Ideally, yes. If not, -netdev tap will continue to blow up in the abort as > > it does > today... > > > > Andrew > > Yes, so the problem is we should prevent tap_enable() and tap_disable() > from being called if multiqueue is disabled. > > I believe the following patch can fix this issue, could you give a try > on this? > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > index c321680..7d091c9 100644 > --- a/hw/net/virtio-net.c > +++ b/hw/net/virtio-net.c > @@ -510,6 +510,10 @@ static int peer_attach(VirtIONet *n, int index) > return 0; > } > > + if (n->max_queues == 1) { > + return 0; > + } > + > return tap_enable(nc->peer); > } >
Yep, this works. Thanks! Andrew
