From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:45662) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hFxJx-0001wd-P1 for qemu-devel@nongnu.org; Mon, 15 Apr 2019 04:50:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hFxJv-0002yP-VA for qemu-devel@nongnu.org; Mon, 15 Apr 2019 04:50:33 -0400 Received: from mail-it1-x12f.google.com ([2607:f8b0:4864:20::12f]:37350) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1hFxJu-0002uv-Co for qemu-devel@nongnu.org; Mon, 15 Apr 2019 04:50:30 -0400 Received: by mail-it1-x12f.google.com with SMTP id u65so25409208itc.2 for ; Mon, 15 Apr 2019 01:50:28 -0700 (PDT) MIME-Version: 1.0 From: fengyd Date: Mon, 15 Apr 2019 16:50:16 +0800 Message-ID: Content-Type: text/plain; charset="UTF-8" Subject: [Qemu-devel] How live migration work for vhost-user List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org 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? Thanks in advance Yafeng