Date: Sun, 14 Jun 2020 23:09:07 +0200 From: Vincenzo Maffione <vmaffione@freebsd.org> To: Jessica Clarke <jrtc27@freebsd.org> Cc: Tom Jones <thj@freebsd.org>, src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r361944 - in head/sys/dev/virtio: . network Message-ID: <CA%2B_eA9gD9vAxy0-6s00nuersBOJ9PjzbMS90sJr9LB9GuhOuww@mail.gmail.com> In-Reply-To: <97EEF019-16A4-4626-A484-A00979B52A74@freebsd.org> References: <202006082151.058LpabU003001@repo.freebsd.org> <20200614195126.GB68578@tom-desk.erg.abdn.ac.uk> <97EEF019-16A4-4626-A484-A00979B52A74@freebsd.org>
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You may already know that, but FreeBSD-CURRENT supports mergeable rx buffers as of r358180. Cheers, Vincenzo Il giorno dom 14 giu 2020 alle ore 22:56 Jessica Clarke <jrtc27@freebsd.org> ha scritto: > On 14 Jun 2020, at 20:51, Tom Jones <thj@freebsd.org> wrote: > > On Mon, Jun 08, 2020 at 09:51:36PM +0000, Jessica Clarke wrote: > >> Author: jrtc27 > >> Date: Mon Jun 8 21:51:36 2020 > >> New Revision: 361944 > >> URL: https://svnweb.freebsd.org/changeset/base/361944 > >> > >> Log: > >> virtio: Support non-legacy network device and queue > >> > >> The non-legacy interface always defines num_buffers in the header, > >> regardless of whether VIRTIO_NET_F_MRG_RXBUF, just leaving it unused. > We > >> also need to ensure our virtqueue doesn't filter out VIRTIO_F_VERSION_1 > >> during negotiation, as it supports non-legacy transports just fine. > This > >> fixes network packet transmission on TinyEMU. > >> > >> Reviewed by: br, brooks (mentor), jhb (mentor) > >> Approved by: br, brooks (mentor), jhb (mentor) > >> Differential Revision: https://reviews.freebsd.org/D25132 > >> > >> Modified: > >> head/sys/dev/virtio/network/if_vtnet.c > >> head/sys/dev/virtio/network/if_vtnetvar.h > >> head/sys/dev/virtio/virtio.c > >> head/sys/dev/virtio/virtqueue.c > >> > > > > Hi Jessica, > > > > After updating my current bhyve vm today (on a 12.1 host), networking no > longer > > works. Reverting this commit seems to resolve the issue. I think vtnet > is not > > passing enough data up to the ip layer. > > > > If I capture on the tap interface for the vm I see arp requests and arp > > replies, however kern.msgbuf is full of: > > > > <5>arp: short packet received on vtnet0 > > > > and netstat does not see any replies to arp requests: > > > > root@freebsd-current:~ # netstat -s -p arp > > arp: > > 11 ARP requests sent > > 0 ARP requests failed to sent > > 0 ARP replies sent > > 0 ARP requests received > > 0 ARP replies received > > 0 ARP packets received > > 24 total packets dropped due to no ARP entry > > 2 ARP entrys timed out > > 0 Duplicate IPs seen > > > > If I set up an arp entry manually I can see ICMP echo requests and > responses on > > the tap interface, but the vm does not see the responses. > > > > root@freebsd-current:~ # netstat -s -p ip > > ip: > > 7 total packets received > > 0 bad header checksums > > 0 with size smaller than minimum > > 7 with data size < data length > > 0 with ip length > max ip packet size > > 0 with header length < data size > > 0 with data length < header length > > > > The line > > > > 7 with data size < data length > > > > makes me think that vtnet is truncating packets. > > > > markj pointed me at this bug in irc which might also be related: > > > > https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=247242 > > Hi Tom, > Sorry about that; it seems bhyve hits the "legacy and no MrgRxBuf" > case. Could you please try the patch below? > > Jess > > diff --git a/sys/dev/virtio/network/if_vtnet.c > b/sys/dev/virtio/network/if_vtnet.c > index 7a0859cc0eb1..7e10b75f7f66 100644 > --- a/sys/dev/virtio/network/if_vtnet.c > +++ b/sys/dev/virtio/network/if_vtnet.c > @@ -1819,9 +1819,10 @@ vtnet_rxq_eof(struct vtnet_rxq *rxq) > adjsz = sizeof(struct vtnet_rx_header); > /* > * Account for our pad inserted between the header > - * and the actual start of the frame. > + * and the actual start of the frame. This includes > + * the unused num_buffers when using a legacy device. > */ > - len += VTNET_RX_HEADER_PAD; > + len += adjsz - sc->vtnet_hdr_size; > } else { > mhdr = mtod(m, struct virtio_net_hdr_mrg_rxbuf *); > nbufs = mhdr->num_buffers; > >
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