From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47566) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bAipm-0001FA-BE for qemu-devel@nongnu.org; Wed, 08 Jun 2016 15:08:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bAiph-0001Ep-49 for qemu-devel@nongnu.org; Wed, 08 Jun 2016 15:08:09 -0400 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:58530 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bAipg-0001DM-QJ for qemu-devel@nongnu.org; Wed, 08 Jun 2016 15:08:05 -0400 Message-ID: <57586D0F.1030705@kamp.de> Date: Wed, 08 Jun 2016 21:07:59 +0200 From: Peter Lieven MIME-Version: 1.0 References: <1465304408-16545-1-git-send-email-pl@kamp.de> <5757BDA0.8090504@redhat.com> <5757C593.3060209@kamp.de> <5757CF4D.9080806@redhat.com> <446837650.20783224.1465381383688.JavaMail.zimbra@redhat.com> In-Reply-To: <446837650.20783224.1465381383688.JavaMail.zimbra@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit 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: Paolo Bonzini , Jason Wang Cc: qemu-devel@nongnu.org, qemu-stable@nongnu.org, hongyang yang Am 08.06.2016 um 12:23 schrieb Paolo Bonzini: > > ----- 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 >> >> >> >> On 2016年06月08日 15:13, Peter Lieven wrote: >>> Am 08.06.2016 um 08:39 schrieb Jason Wang: >>>> On 2016年06月07日 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-net >>>>> 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. [Paolo] >>>>> >>>>> 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 = 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 something >>>>> like >>>>> + * .receive_raw_iov in NetClientInfo first. */ >>>>> + assert(!(flags & QEMU_NET_PACKET_FLAG_RAW) || iovcnt == 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 = nc->info->receive_raw(nc, iov[0].iov_base, >>>>> iov[0].iov_len); >>>>> + } else if (nc->info->receive_iov) { >>>>> ret = nc->info->receive_iov(nc, iov, iovcnt); >>>>> } else { >>>>> ret = nc_sendv_compat(nc, iov, iovcnt, flags); >>>> We still have raw packet support in nv_sendv_compat, can we use it? (and >>>> 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 I should have looked into this nc_sendv_compat function before ;-) This indeed is the best solution I think. Will send a v3 tomorrow. Peter