From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36888) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c5FNM-0007bg-Ls for qemu-devel@nongnu.org; Fri, 11 Nov 2016 12:12:29 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c5FNH-00016m-J3 for qemu-devel@nongnu.org; Fri, 11 Nov 2016 12:12:28 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55572) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1c5FNH-00016P-Dh for qemu-devel@nongnu.org; Fri, 11 Nov 2016 12:12:23 -0500 Date: Fri, 11 Nov 2016 19:12:20 +0200 From: "Michael S. Tsirkin" Message-ID: <20161111191020-mutt-send-email-mst@kernel.org> References: <1477293002-144213-1-git-send-email-wei.w.wang@intel.com> <5821B884.5080309@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [virtio-comment] Re: [PATCH v1] docs/vhost-user: extend the vhost-user protocol to support the vhost-pci based inter-vm communication List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?iso-8859-1?Q?Marc-Andr=E9?= Lureau Cc: Wei Wang , virtio-comment@lists.oasis-open.org, qemu-devel@nongnu.org, stefanha@redhat.com, pbonzini@redhat.com On Tue, Nov 08, 2016 at 12:17:38PM +0000, Marc-Andr=E9 Lureau wrote: > Yes, that's the trouble. At any time the Master may send a request and = expects > an immediate reply. There is a race of getting a request from the Slave= in the > middle with your proposed change. I'd rather avoid making the request > bidirectionnal if possible. (I proposed a second channel for Slave->Mas= ter > request in the past: https://lists.gnu.org/archive/html/qemu-devel/2016= -04/ > msg00095.html) I don't have an issue with this, but supporting commands from slave on the same channel shouldn't be too hard too, and it's less work for the management. --=20 MST