From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35932) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gRCrv-0002eu-UP for qemu-devel@nongnu.org; Mon, 26 Nov 2018 04:07:52 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gRCrs-0003VX-1v for qemu-devel@nongnu.org; Mon, 26 Nov 2018 04:07:51 -0500 Received: from szxga02-in.huawei.com ([45.249.212.188]:2351 helo=huawei.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gRCrq-0003T5-0W for qemu-devel@nongnu.org; Mon, 26 Nov 2018 04:07:47 -0500 From: linzhecheng Date: Mon, 26 Nov 2018 09:07:32 +0000 Message-ID: References: <20181126064611.zgsxden3jemuglaj@sirius.home.kraxel.org> <20181126084933.jdlxzj6l7lq5kubg@sirius.home.kraxel.org> In-Reply-To: <20181126084933.jdlxzj6l7lq5kubg@sirius.home.kraxel.org> Content-Language: zh-CN Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [Qemu-devel] [question] live migration about redir-usb List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann Cc: "qemu-devel@nongnu.org" , "wangxin (U)" , "Zhoujian (jay)" > -----Original Message----- > From: Gerd Hoffmann [mailto:kraxel@redhat.com] > Sent: Monday, November 26, 2018 4:50 PM > To: linzhecheng > Cc: qemu-devel@nongnu.org; wangxin (U) ; > Zhoujian (jay) > Subject: Re: [Qemu-devel] [question] live migration about redir-usb >=20 > On Mon, Nov 26, 2018 at 06:53:23AM +0000, linzhecheng wrote: > > > > > > > -----Original Message----- > > > From: Gerd Hoffmann [mailto:kraxel@redhat.com] > > > Sent: Monday, November 26, 2018 2:46 PM > > > To: linzhecheng > > > Cc: qemu-devel@nongnu.org; wangxin (U) > ; > > > Zhoujian (jay) > > > Subject: Re: [Qemu-devel] [question] live migration about redir-usb > > > > > > On Mon, Nov 26, 2018 at 02:29:12AM +0000, linzhecheng wrote: > > > > Hi, Gerd > > > > I have read this discussion thread about live migration in tcp mode= . > > > > https://bugzilla.redhat.com/show_bug.cgi?id=3D1254971 > > > > Only spice redirection supports live migration not, but why not tcp= mode? > > > > Does usbredirserver not support it or qemu? > > > > > > usbredirserver. > > > > > > spice client holds a connection to both source and target host for a > > > seamless connection handover, and usb-redir needs that too to hand > > > over the usb device without interruption. > > > > > > usbredirserver can't do that. >=20 > > So if we realize the handover between src and dst chardev of qemu, we > > can do live migration in tcp mode. >=20 > > Is it similar with openvswtich who both accept the connection of src an= d dst > qemu? >=20 > It is more complicated than just accepting two connections. Network can = just > throw away packages if needed, typicaly they will be resent by the guest.= That > doesn't work with usb, you must properly keep track of every in-flight us= b > transfer. Why will network throw away packets? I think inflight usb Packets have already been tracked by redir-usb in live migration. What's m= ore do we have to do? >=20 > What exactly do you want do? Realize live migration for redir-usb in tcp mode. >=20 > Maybe it will be simpler to build a stripped-down spice client with only = the usb > redir code, which doesn't require a UI and which you can start from the > command line like usbredirserver? Most spice client code is actually in = shared > libraries, so it should not be too much work. >=20 > cheers, > Gerd