From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46603) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bAady-0001eX-MQ for qemu-devel@nongnu.org; Wed, 08 Jun 2016 06:23:27 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bAadw-0001Bz-EW for qemu-devel@nongnu.org; Wed, 08 Jun 2016 06:23:25 -0400 Date: Wed, 8 Jun 2016 06:23:03 -0400 (EDT) From: Paolo Bonzini Message-ID: <446837650.20783224.1465381383688.JavaMail.zimbra@redhat.com> In-Reply-To: <5757CF4D.9080806@redhat.com> References: <1465304408-16545-1-git-send-email-pl@kamp.de> <5757BDA0.8090504@redhat.com> <5757C593.3060209@kamp.de> <5757CF4D.9080806@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [Qemu-stable] [PATCH V2] net: fix qemu_announce_self not emitting packets List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jason Wang Cc: Peter Lieven , qemu-devel@nongnu.org, qemu-stable@nongnu.org, hongyang yang ----- Original Message ----- > From: "Jason Wang" > To: "Peter Lieven" , qemu-devel@nongnu.org > Cc: pbonzini@redhat.com, qemu-stable@nongnu.org, "hongyang yang" > Sent: Wednesday, June 8, 2016 9:54:53 AM > Subject: Re: [Qemu-devel] [Qemu-stable] [PATCH V2] net: fix qemu_announce= _self not emitting packets >=20 >=20 >=20 > On 2016=E5=B9=B406=E6=9C=8808=E6=97=A5 15:13, Peter Lieven wrote: > > Am 08.06.2016 um 08:39 schrieb Jason Wang: > >> > >> On 2016=E5=B9=B406=E6=9C=8807=E6=97=A5 21:00, Peter Lieven wrote: > >>> commit fefe2a78 accidently dropped the code path for injecting > >>> raw packets. This feature is needed for sending gratuitous ARPs > >>> after an incoming migration has completed. The result is increased > >>> network downtime for vservers where the network card is not virtio-ne= t > >>> with the VIRTIO_NET_F_GUEST_ANNOUNCE feature. > >>> > >>> Fixes: fefe2a78abde932e0f340b21bded2c86def1d242 > >>> Cc: qemu-stable@nongnu.org > >>> Cc: hongyang.yang@easystack.cn > >>> Signed-off-by: Peter Lieven > >>> --- > >>> v1->v2: assert that only raw packets with a plain buffer come in. [Pa= olo] > >>> > >>> net/net.c | 10 +++++++++- > >>> 1 file changed, 9 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/net/net.c b/net/net.c > >>> index 5f3e5a9..5e1b5fa 100644 > >>> --- a/net/net.c > >>> +++ b/net/net.c > >>> @@ -714,6 +714,11 @@ ssize_t qemu_deliver_packet_iov(NetClientState > >>> *sender, > >>> NetClientState *nc =3D opaque; > >>> int ret; > >>> + /* we currently only support sending raw packets via > >>> qemu_send_packet_raw. > >>> + * If we want generic raw iov support we need to implement somet= hing > >>> like > >>> + * .receive_raw_iov in NetClientInfo first. */ > >>> + assert(!(flags & QEMU_NET_PACKET_FLAG_RAW) || iovcnt =3D=3D 1); > >>> + > >>> if (nc->link_down) { > >>> return iov_size(iov, iovcnt); > >>> } > >>> @@ -722,7 +727,10 @@ ssize_t qemu_deliver_packet_iov(NetClientState > >>> *sender, > >>> return 0; > >>> } > >>> - if (nc->info->receive_iov) { > >>> + if (flags & QEMU_NET_PACKET_FLAG_RAW && nc->info->receive_raw) { > >>> + /* this is required for qemu_announce_self() */ > >>> + ret =3D nc->info->receive_raw(nc, iov[0].iov_base, > >>> iov[0].iov_len); > >>> + } else if (nc->info->receive_iov) { > >>> ret =3D nc->info->receive_iov(nc, iov, iovcnt); > >>> } else { > >>> ret =3D nc_sendv_compat(nc, iov, iovcnt, flags); > >> We still have raw packet support in nv_sendv_compat, can we use it? (a= nd > >> then there's no need for the assert above). > > Okay, so Version 1 of the patch is more appropiate. I would either use = V1 > > or revert fefe2a78. The issue is quite serious > > for live migration. Or you can do even simpler: if (nc->info->receive_iov && !(flags & QEMU_NET_PACKET_FLAG_RAW))) nc->info->receive_iov else nc_sendv_compat Paolo > > > > Peter > > > > >=20 > V1 checks iovcnt and call receive_raw with hard coded first iov. Since > we have raw packet support in nc_sendv_compat(), I mean when we detect > QEMU_NET_PACKET_FLAG_RAW, call nc_sendv_compat() here. >=20