From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:52969) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hL8vt-0004bu-Dg for qemu-devel@nongnu.org; Mon, 29 Apr 2019 12:15:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hL8vr-0008Ky-RR for qemu-devel@nongnu.org; Mon, 29 Apr 2019 12:15:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58274) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hL8vr-0008Hj-Ct for qemu-devel@nongnu.org; Mon, 29 Apr 2019 12:15:07 -0400 Date: Mon, 29 Apr 2019 17:15:02 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20190429161502.GI2748@work-vm> References: <20190415145358.GA2893@work-vm> <20190416084738.GA3123@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] Fwd: How live migration work for vhost-user List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: fengyd Cc: qemu-devel@nongnu.org * fengyd (fengyd81@gmail.com) wrote: > Hi, > > I want to add some log to qemu-kvm-ev. > Do you know how to compile qemu-kvm-ev from source code? That's our downstream package build; it should build fine with rpmbuild, or you can configure and build it like any other qemu. Dave > Thanks > > Yafeng > > On Tue, 16 Apr 2019 at 16:47, Dr. David Alan Gilbert > wrote: > > > * fengyd (fengyd81@gmail.com) wrote: > > > ---------- Forwarded message --------- > > > From: fengyd > > > Date: Tue, 16 Apr 2019 at 09:17 > > > Subject: Re: [Qemu-devel] How live migration work for vhost-user > > > To: Dr. David Alan Gilbert > > > > > > > > > Hi, > > > > > > Any special feature needs to be supported on guest driver? > > > Because it's OK for standard Linux VM, but not OK for our VM where virtio > > > is implemented by ourself. > > > > I'm not sure; you do have to support that 'log' mechanism but I don't > > know what else is needed. > > > > > And with qemu-kvm-ev-2.6, live migration can work with our VM where > > virtio > > > is implemented by ourself. > > > > 2.6 is pretty old, so there's a lot of changes - not sure what's > > relevant. > > > > Dave > > > > > Thanks > > > Yafeng > > > > > > On Mon, 15 Apr 2019 at 22:54, Dr. David Alan Gilbert < > > dgilbert@redhat.com> > > > wrote: > > > > > > > * fengyd (fengyd81@gmail.com) wrote: > > > > > Hi, > > > > > > > > > > During live migration, the folloing log can see in nova-compute.log > > in > > > > my > > > > > environment: > > > > > ERROR nova.virt.libvirt.driver > > [req-039a85e1-e7a1-4a63-bc6d-c4b9a044aab6 > > > > > 0cdab20dc79f4bc6ae5790e7b4a898ac 3363c319773549178acc67f32c78310e - > > > > default > > > > > default] [instance: 5ec719f4-1865-4afe-a207-3d9fae22c410] Live > > Migration > > > > > failure: internal error: qemu unexpectedly closed the monitor: > > > > > 2019-04-15T02:58:22.213897Z qemu-kvm: VQ 0 > > > > > size 0x100 < last_avail_idx 0x1e - used_idx 0x23 > > > > > > > > > > It's OK for standard Linux VM, but not OK for our VM where virtio is > > > > > implemented by ourself. > > > > > KVM version as follow: > > > > > qemu-kvm-common-ev-2.12.0-18.el7_6.3.1.x86_64 > > > > > qemu-kvm-ev-2.12.0-18.el7_6.3.1.x86_64 > > > > > libvirt-daemon-kvm-3.9.0-14.2.el7.centos.ncir.8.x86_64 > > > > > > > > > > Do you know what's the difference between virtio and vhost-user > > during > > > > > migration? > > > > > The function virtio_load in Qemu is called for virtio and vhost-user > > > > during > > > > > migration. > > > > > For virtio, last_avail_idx and used_idx are stored in Qemu, Qemu is > > > > > responsible for updating their values accordingly > > > > > For vhost-user, last_avail_idx and used_idx are stored in vhost-user > > > > app, > > > > > eg. DPDK, not in Qemu? > > > > > How does migration work for vhost-user? > > > > > > > > I don't know the details, but my understanding is that vhost-user > > > > tells the vhost-user client about an area of 'log' memory, where the > > > > vhost-user client must mark pages as dirty. > > > > > > > > In the qemu source, see docs/interop/vhost-user.txt and see > > > > the VHOST_SET_LOG_BASE and VHOST_USER_SET_LOG_FD calls. > > > > > > > > If the client correctly marks the areas as dirty, then qemu > > > > should resend those pages across. > > > > > > > > > > > > Dave > > > > > > > > > Thanks in advance > > > > > Yafeng > > > > -- > > > > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK > > > > > > -- > > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK