From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45949) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YGqya-0006Yy-Go for qemu-devel@nongnu.org; Thu, 29 Jan 2015 10:25:52 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YGqyX-0006ik-4b for qemu-devel@nongnu.org; Thu, 29 Jan 2015 10:25:48 -0500 Received: from mx1.redhat.com ([209.132.183.28]:40652) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YGqyW-0006iS-UL for qemu-devel@nongnu.org; Thu, 29 Jan 2015 10:25:45 -0500 Message-ID: <54CA50F0.9050100@redhat.com> Date: Thu, 29 Jan 2015 08:25:36 -0700 From: Eric Blake MIME-Version: 1.0 References: <1422543997-22808-1-git-send-email-dgilbert@redhat.com> In-Reply-To: <1422543997-22808-1-git-send-email-dgilbert@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="xp3RoIpMnFo4BusFoU2tbdhFHQu1ovwLC" Subject: Re: [Qemu-devel] [RFC 0/1] Incoming migration vs early monitor commands List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert (git)" , qemu-devel@nongnu.org Cc: amit.shah@redhat.com, liang.z.li@intel.com, quintela@redhat.com This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --xp3RoIpMnFo4BusFoU2tbdhFHQu1ovwLC Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 01/29/2015 08:06 AM, Dr. David Alan Gilbert (git) wrote: > From: "Dr. David Alan Gilbert" >=20 > The attached patch allows you to execute QMP commands from the command > line prior to -incoming or loadvm. >=20 > I've hit a few cases where we need to pass some state to an incoming > migration, either: > 1) Before it starts processing data > e.g. Liang Li's compression patches that have a parameter for the > number of decompression threads >=20 > 2) Before the socket is set up > so we can influence the connection made; e.g. specify we need to > have a return path for postcopy, or potentially open multiple conne= ctions >=20 > For tcp migration you can use the monitor for (1) prior to the accept; > but it's no use for exec or fd. >=20 > I'd previously suggested adding option parsing to the -incoming URI; That may still be feasible; we have QemuOpts for that purpose. > but > then I realised just being able to execute arbitrary QMP commands might= > be simpler, and we get reuse of all the migrate capability/parameter > stuff for free, and maybe the arbitrary QMP commands are useful for > something else. It feels like command-line QMP would be write-only - there's no sane way to issue query commands and react to what was queried. The full power of QMP is made possible with a bidirectional path, but the command line is not bidirectional. This hack may have uses, but I'm not sure it is my first choice for any situation. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --xp3RoIpMnFo4BusFoU2tbdhFHQu1ovwLC Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJUylDwAAoJEKeha0olJ0Nq1w4H/jbAti6snvd3JFLecQN18iyp 93naXwS78ksYglyXONYoM8p58UpJueIqwlBwPanGeXxnx4ft4D2KXQmrOtfH5y1g BlzWxXNaViEgQjQLTaJs92kZJyUiyX/CErWR8DeDgOQ2ouo0ls82E1VFP+PsOEwB Bbgeg4KyCUt+SxPyYJ5R+OPykdVWCo4TmDORDTZIZvBzPNlzuFnfWHfE6//gL93w CSeoqoeXJLYWgT8uX1Fp719LXZl/8U9C66pmJEDZl5hPHO9B9pdYasc0WgkM/leA 2JK1crp46MGsoiUqqIJSOsgQyBeVQBX1RGbOSpfK+ZZfyRB0CCzM3HrFEubLjHo= =wBj4 -----END PGP SIGNATURE----- --xp3RoIpMnFo4BusFoU2tbdhFHQu1ovwLC--