From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36378) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dIfjG-0002Qk-Uc for qemu-devel@nongnu.org; Wed, 07 Jun 2017 14:30:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dIfjC-0004TD-1B for qemu-devel@nongnu.org; Wed, 07 Jun 2017 14:30:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57758) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dIfjB-0004Sy-RT for qemu-devel@nongnu.org; Wed, 07 Jun 2017 14:30:45 -0400 Date: Wed, 7 Jun 2017 21:30:43 +0300 From: "Michael S. Tsirkin" Message-ID: <20170607212825-mutt-send-email-mst@kernel.org> References: <20170607152825.12081-1-pbonzini@redhat.com> <20170607152825.12081-2-pbonzini@redhat.com> <8229C6EB-56EA-475E-99D4-6D9B36B5D0A7@nutanix.com> <7a06506e-20ba-66b8-8c69-c500efe86301@redhat.com> <0281E149-DE28-4D6D-80E0-1132CAB8ABDB@nutanix.com> <1265195474.6852496.1496859744613.JavaMail.zimbra@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1265195474.6852496.1496859744613.JavaMail.zimbra@redhat.com> Subject: Re: [Qemu-devel] [PULL 18/33] vhost-user-scsi: Introduce vhost-user-scsi host device List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: Felipe Franciosi , Peter Maydell , QEMU Developers On Wed, Jun 07, 2017 at 02:22:24PM -0400, Paolo Bonzini wrote: > > > How, since there is no synchronization point between the vhost-user > > > server on the source and the destination? > > > > The idea is that the backend should both stop picking up new requests and > > also quiesce outstanding requests upon a GET_VRING_BASE vhost message. > > This could be documented, It is documented AFAIK. Pls take a look at the spec documentation. > but perhaps it's best to add a START_STOP > feature and message to the vhost-user protocol? We just never need to GET_VRING_BASE if ring keeps going - makes no sense since base gets invalidated immediately. > The feature then can be optional for vhost-user-net and mandatory for > vhost-user-scsi. When this is done we can remove .unmigratable. > > Thanks, > > Paolo If vhost-user-scsi does not stop the ring after responding to GET_VRING_BASE, it's just a bug that needs to be fixed. > > > > > > Can you please send a version of your patch that uses .unmigratable? > > > > Sure I can do that. We can work on the migration later on. > > > > > > > > I'll send a v6 that momentarily drops vhost-scsi, but I intend to > > > include it again in the next pull request. > > > > Sounds good to me. > > > > Felipe > > > > > > > > Thanks, > > > > > > Paolo > > > >