From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53007) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XqbY7-0000WE-Jo for qemu-devel@nongnu.org; Tue, 18 Nov 2014 00:42:03 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XqbXx-0005c5-2Q for qemu-devel@nongnu.org; Tue, 18 Nov 2014 00:41:59 -0500 Received: from ozlabs.org ([103.22.144.67]:53504) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XqbXw-0005bN-OK for qemu-devel@nongnu.org; Tue, 18 Nov 2014 00:41:49 -0500 Date: Tue, 18 Nov 2014 14:53:17 +1100 From: David Gibson Message-ID: <20141118035317.GB2867@voom.redhat.com> References: <1412358473-31398-1-git-send-email-dgilbert@redhat.com> <1412358473-31398-13-git-send-email-dgilbert@redhat.com> <20141103031244.GH8949@voom.redhat.com> <8617F122-9356-492C-B663-62C101F5EE6B@cs.umu.se> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="p4qYPpj5QlsIQJ0K" Content-Disposition: inline In-Reply-To: <8617F122-9356-492C-B663-62C101F5EE6B@cs.umu.se> Subject: Re: [Qemu-devel] [PATCH v4 12/47] Handle bi-directional communication for fd migration List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Cristian Klein Cc: Andrea Arcangeli , yamahata@private.email.ne.jp, lilei@linux.vnet.ibm.com, quintela@redhat.com, "Dr. David Alan Gilbert" , qemu-devel@nongnu.org, amit.shah@redhat.com, yanghy@cn.fujitsu.com --p4qYPpj5QlsIQJ0K Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Nov 03, 2014 at 03:53:03PM +0200, Cristian Klein wrote: > On 03 Nov 2014, at 5:12 , David Gibson wrot= e: >=20 > > On Fri, Oct 03, 2014 at 06:47:18PM +0100, Dr. David Alan Gilbert (git) = wrote: > >> From: Cristian Klein > >=20 > > This patch really, really requires a rationale in the commit message. > > The reason it's necessary is certainly not obvious. >=20 > =E2=80=9C=E2=80=9D" > libvirt prefers opening the TCP connection itself, for two reasons. First= , connection failed errors can be detected easier, without having to parse = qemu=E2=80=99s error output. Second, libvirt might be asked to secure the t= ransfer by tunnelling the communication through an TLS layer. Therefore, li= bvirt opens the TCP connection itself and passes an FD to qemu using QMP an= d a POSIX-specific mechanism. Hence, in order to make the reverse-path work= in such cases, qemu needs to distinguish if the transmitted FD is a socket= (reverse-path available) or not (reverse-path might not be available) and = use the corresponding abstraction. > =E2=80=9C=E2=80=9D" >=20 > If the above message is clarifies the purpose of this commit, feel > free to add it in the next version of the patch. That would help, yes. --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson --p4qYPpj5QlsIQJ0K Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJUasKtAAoJEGw4ysog2bOSdfMQAJkXUvXfdT/EAmNTPEVxu9Nt Inj8Quc46rboVWHGv/Ke9BxYrDq2QzbomZoZox41aIoh5lB/m1kVGwF4BjdYM4Oy e7gT14M1dXSRLZm3PC+kwkUSGaFeFxVV6TfnZqaFR/3OCLIDYsZ7BtDEJ7q8drxz nuiXU4ygRo/oi6fDhdJILNbHD3nPez96vy8uOpq9ydoOAYLGMZfoC/1oXOwXPoLr X68VnrQtwyS8UjAmU2qRGaXHn7MYc1KoaZJjPDC0jX46RO72g8hkqgLUiB1+lMv4 NVYZcWzOJL246I7YkMnJHl9PZBePXrW0n2cTGNjq2mjh/LXFzrVhFWP5UwSTQZjm FTpmqjxbQoiCl7aoxSpWHyuy8qcon85hX+NfVNblK2+0ZveqYHyVmi+IMDNA17m0 sabUvbb8kas3/A+0b5djH0vNuJ3yRBAXHbMNBGofUcadtKEW+50xRd2Lta+zgnmW 75nYGLK8yaslewkrm7yHMXdo6gUvy6HQZwaA2ywSDYdj0eN/3o9hKU87cJn+iVPq 8gJOxiyR56xqj5sdFCoBeeyZEh9ysyZyggTfwkfLrbIlAJyseVMIK6SQFJXCXp9l Ye63LObyroSt45gg19whBM9XkWctVmUOTXlInvM15/FUao1AbPIP2qcyHpB0PzHA yf60bIc7XBHZFVdVoqL8 =4IUW -----END PGP SIGNATURE----- --p4qYPpj5QlsIQJ0K--