From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:39727) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hFyy6-0001L4-Oj for qemu-devel@nongnu.org; Mon, 15 Apr 2019 06:36:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hFyy5-0005qP-Bj for qemu-devel@nongnu.org; Mon, 15 Apr 2019 06:36:06 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:34536) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hFyy4-0005pn-Rp for qemu-devel@nongnu.org; Mon, 15 Apr 2019 06:36:05 -0400 Date: Mon, 15 Apr 2019 13:35:47 +0300 From: Yuval Shaia Message-ID: <20190415103546.GA6854@lap1> References: <20190411110157.14252-1-yuval.shaia@oracle.com> <20190411190215.2163572e.cohuck@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190411190215.2163572e.cohuck@redhat.com> Subject: Re: [Qemu-devel] [RFC 0/3] VirtIO RDMA List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Cornelia Huck Cc: virtualization@lists.linux-foundation.org, qemu-devel@nongnu.org, mst@redhat.com, marcel.apfelbaum@gmail.com, linux-rdma@vger.kernel.org, jgg@mellanox.com On Thu, Apr 11, 2019 at 07:02:15PM +0200, Cornelia Huck wrote: > On Thu, 11 Apr 2019 14:01:54 +0300 > Yuval Shaia wrote: > > > Data center backends use more and more RDMA or RoCE devices and more and > > more software runs in virtualized environment. > > There is a need for a standard to enable RDMA/RoCE on Virtual Machines. > > > > Virtio is the optimal solution since is the de-facto para-virtualizaton > > technology and also because the Virtio specification > > allows Hardware Vendors to support Virtio protocol natively in order to > > achieve bare metal performance. > > > > This RFC is an effort to addresses challenges in defining the RDMA/RoCE > > Virtio Specification and a look forward on possible implementation > > techniques. > > > > Open issues/Todo list: > > List is huge, this is only start point of the project. > > Anyway, here is one example of item in the list: > > - Multi VirtQ: Every QP has two rings and every CQ has one. This means that > > in order to support for example 32K QPs we will need 64K VirtQ. Not sure > > that this is reasonable so one option is to have one for all and > > multiplex the traffic on it. This is not good approach as by design it > > introducing an optional starvation. Another approach would be multi > > queues and round-robin (for example) between them. > > > > Expectations from this posting: > > In general, any comment is welcome, starting from hey, drop this as it is a > > very bad idea, to yeah, go ahead, we really want it. > > Idea here is that since it is not a minor effort i first want to know if > > there is some sort interest in the community for such device. > > My first reaction is: Sounds sensible, but it would be good to have a > spec for this :) > > You'll need a spec if you want this to go forward anyway, so at least a > sketch would be good to answer questions such as how many virtqueues > you use for which purpose, what is actually put on the virtqueues, > whether there are negotiable features, and what the expectations for > the device and the driver are. It also makes it easier to understand > how this is supposed to work in practice. > > If folks agree that this sounds useful, the next step would be to > reserve an id for the device type. Thanks for the tips, will sure do that, it is that first i wanted to make sure there is a use case here. Waiting for any feedback from the community. > > > > > The scope of the implementation is limited to probing the device and doing > > some basic ibverbs commands. Data-path is not yet implemented. So with this > > one can expect only that driver is (partialy) loaded and basic queries and > > resource allocation is done. > > > > One note regarding the patchset. > > I know it is not standard to collaps patches from several repos as i did > > here (qemu and linux) but decided to do it anyway so the whole picture can > > be seen. > > > > patch 1: virtio-net: Move some virtio-net-pci decl to include/hw/virtio > > This is a prelimenary patch just as a hack so i will not need to > > impelement new netdev > > patch 2: hw/virtio-rdma: VirtIO rdma device > > The implementation of the device > > patch 3: RDMA/virtio-rdma: VirtIO rdma driver > > The device driver > > > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81357C10F0E for ; 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Mon, 15 Apr 2019 06:36:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hFyy5-0005qP-Bj for qemu-devel@nongnu.org; Mon, 15 Apr 2019 06:36:06 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:34536) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hFyy4-0005pn-Rp for qemu-devel@nongnu.org; Mon, 15 Apr 2019 06:36:05 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x3FATA5k154348; Mon, 15 Apr 2019 10:35:56 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2018-07-02; bh=y3V9ndy/Qm5yVBdn+YrDF4jd95IBdj4M6Ir3QrTHJOA=; b=LwPE2go3ika4GfcdL/mqQFwLnSf42Y9Gwoo6Z8+LegQpSIEzagjefWXYueDkMLNj/32G kcnJ8SS6wqIA8zQV91UCmSuqHDviaWX6o4ulU2/z1DFz7JW2eQPB2Ow66VT3Jx53aqjN pQsXZOKz+qRXSY8etzOom+/vrxwVJH7uWkTagfIz/W3JKLPdp/M0hsWzHmjLQqhabOxG myuVBjj+snviCCvg6T/bdA+b3jWKqokIQRuBXj1kwsH5wnNmaaLtkJ1+15juJwlJBn8m BfCGNL+ZxUaVnpK5rdjyffrUyfg1OjQFOlCEP6ZJVUCD/xM9dhM0zAP6zjY2a/jHK9CG NQ== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2120.oracle.com with ESMTP id 2rusnekvb8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 15 Apr 2019 10:35:56 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x3FAY3tk188212; Mon, 15 Apr 2019 10:35:55 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserp3030.oracle.com with ESMTP id 2ru5ta8vpw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 15 Apr 2019 10:35:55 +0000 Received: from abhmp0006.oracle.com (abhmp0006.oracle.com [141.146.116.12]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x3FAZs7M000534; Mon, 15 Apr 2019 10:35:54 GMT Received: from lap1 (/77.138.183.59) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 15 Apr 2019 03:35:54 -0700 Date: Mon, 15 Apr 2019 13:35:47 +0300 From: Yuval Shaia To: Cornelia Huck Message-ID: <20190415103546.GA6854@lap1> References: <20190411110157.14252-1-yuval.shaia@oracle.com> <20190411190215.2163572e.cohuck@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline In-Reply-To: <20190411190215.2163572e.cohuck@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9227 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904150074 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9227 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904150074 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] X-Received-From: 156.151.31.85 Subject: Re: [Qemu-devel] [RFC 0/3] VirtIO RDMA X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mst@redhat.com, linux-rdma@vger.kernel.org, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, jgg@mellanox.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190415103547.2GxNeS6WBzZnT-AEhTs3uXgWHQA8csYrX2Nwkqrdy9o@z> On Thu, Apr 11, 2019 at 07:02:15PM +0200, Cornelia Huck wrote: > On Thu, 11 Apr 2019 14:01:54 +0300 > Yuval Shaia wrote: > > > Data center backends use more and more RDMA or RoCE devices and more and > > more software runs in virtualized environment. > > There is a need for a standard to enable RDMA/RoCE on Virtual Machines. > > > > Virtio is the optimal solution since is the de-facto para-virtualizaton > > technology and also because the Virtio specification > > allows Hardware Vendors to support Virtio protocol natively in order to > > achieve bare metal performance. > > > > This RFC is an effort to addresses challenges in defining the RDMA/RoCE > > Virtio Specification and a look forward on possible implementation > > techniques. > > > > Open issues/Todo list: > > List is huge, this is only start point of the project. > > Anyway, here is one example of item in the list: > > - Multi VirtQ: Every QP has two rings and every CQ has one. This means that > > in order to support for example 32K QPs we will need 64K VirtQ. Not sure > > that this is reasonable so one option is to have one for all and > > multiplex the traffic on it. This is not good approach as by design it > > introducing an optional starvation. Another approach would be multi > > queues and round-robin (for example) between them. > > > > Expectations from this posting: > > In general, any comment is welcome, starting from hey, drop this as it is a > > very bad idea, to yeah, go ahead, we really want it. > > Idea here is that since it is not a minor effort i first want to know if > > there is some sort interest in the community for such device. > > My first reaction is: Sounds sensible, but it would be good to have a > spec for this :) > > You'll need a spec if you want this to go forward anyway, so at least a > sketch would be good to answer questions such as how many virtqueues > you use for which purpose, what is actually put on the virtqueues, > whether there are negotiable features, and what the expectations for > the device and the driver are. It also makes it easier to understand > how this is supposed to work in practice. > > If folks agree that this sounds useful, the next step would be to > reserve an id for the device type. Thanks for the tips, will sure do that, it is that first i wanted to make sure there is a use case here. Waiting for any feedback from the community. > > > > > The scope of the implementation is limited to probing the device and doing > > some basic ibverbs commands. Data-path is not yet implemented. So with this > > one can expect only that driver is (partialy) loaded and basic queries and > > resource allocation is done. > > > > One note regarding the patchset. > > I know it is not standard to collaps patches from several repos as i did > > here (qemu and linux) but decided to do it anyway so the whole picture can > > be seen. > > > > patch 1: virtio-net: Move some virtio-net-pci decl to include/hw/virtio > > This is a prelimenary patch just as a hack so i will not need to > > impelement new netdev > > patch 2: hw/virtio-rdma: VirtIO rdma device > > The implementation of the device > > patch 3: RDMA/virtio-rdma: VirtIO rdma driver > > The device driver > > >