Date: Sun, 14 Jun 2020 21:56:03 +0100 From: Jessica Clarke <jrtc27@freebsd.org> To: Tom Jones <thj@freebsd.org> Cc: 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: <97EEF019-16A4-4626-A484-A00979B52A74@freebsd.org> In-Reply-To: <20200614195126.GB68578@tom-desk.erg.abdn.ac.uk> References: <202006082151.058LpabU003001@repo.freebsd.org> <20200614195126.GB68578@tom-desk.erg.abdn.ac.uk>
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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 >>=20 >> Log: >> virtio: Support non-legacy network device and queue >>=20 >> 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. >>=20 >> Reviewed by: br, brooks (mentor), jhb (mentor) >> Approved by: br, brooks (mentor), jhb (mentor) >> Differential Revision: https://reviews.freebsd.org/D25132 >>=20 >> 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 >>=20 >=20 > Hi Jessica, >=20 > 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. >=20 > If I capture on the tap interface for the vm I see arp requests and = arp > replies, however kern.msgbuf is full of:=20 >=20 > <5>arp: short packet received on vtnet0 >=20 > and netstat does not see any replies to arp requests: >=20 > 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 >=20 > 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.=20 >=20 > 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 >=20 > The line >=20 > 7 with data size < data length >=20 > makes me think that vtnet is truncating packets.=20 >=20 > markj pointed me at this bug in irc which might also be related: >=20 > https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D247242 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 =3D 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 +=3D VTNET_RX_HEADER_PAD; + len +=3D adjsz - sc->vtnet_hdr_size; } else { mhdr =3D mtod(m, struct virtio_net_hdr_mrg_rxbuf *); nbufs =3D mhdr->num_buffers;
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