From: Stefan Hajnoczi <stefanha@gmail.com>
To: Catalin Vasile <cata.vasile@nxp.com>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [virtio-net] migration
Date: Thu, 9 Jun 2016 13:59:38 +0100 [thread overview]
Message-ID: <20160609125938.GG15369@stefanha-x1.localdomain> (raw)
In-Reply-To: <HE1PR04MB1306F8A87CE19B0FCF9D3A67EE420@HE1PR04MB1306.eurprd04.prod.outlook.com>
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On Fri, May 27, 2016 at 12:59:51PM +0000, Catalin Vasile wrote:
> What is the workflow for virtio-net devices when migrating the VM it belongs to?
> From what I understand so far the stop() primitives in qemu are called for virtio_net and vhost_net which makes the virtqueue reset such that it seems the queues are completely empty.
> How does the guest know that the jobs he sent on the virtqueue were discarded so that he can retry or release resources that were used for managing those jobs/packets?
No, virtqueues stay as-is across migration. vring state (e.g.
last_avail_idx) is migrated so that the new QEMU can pick up where the
old one left off.
See hw/virtio/virtio.c load/save code to learn more.
Stefan
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prev parent reply other threads:[~2016-06-09 12:59 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-27 12:59 [Qemu-devel] [virtio-net] migration Catalin Vasile
2016-06-09 12:59 ` Stefan Hajnoczi [this message]
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