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=-0.3 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 53310C433DF for ; Mon, 25 May 2020 16:17:02 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1D5BF2071A for ; Mon, 25 May 2020 16:17:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="j+nJi5Sf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1D5BF2071A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:48782 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jdFmf-0001on-Aw for qemu-devel@archiver.kernel.org; Mon, 25 May 2020 12:17:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33580) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jdFlX-00017d-Vp for qemu-devel@nongnu.org; Mon, 25 May 2020 12:15:52 -0400 Received: from mail-qv1-xf44.google.com ([2607:f8b0:4864:20::f44]:46764) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jdFlU-00050b-DW for qemu-devel@nongnu.org; Mon, 25 May 2020 12:15:51 -0400 Received: by mail-qv1-xf44.google.com with SMTP id dh1so8185439qvb.13 for ; Mon, 25 May 2020 09:15:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=v5caC1qoDQHmpMSdvWXR9hOq/bI0FBDMIPeurKroVVk=; b=j+nJi5Sf5wW1EgQn7lwu7GvwIXVivIMZNrmPUQzAIP1EmUA/onkJE9+NbGO4NtbfUL FMcwvZu8gZ7YWZfa7TbNNHv816EMXCkUc5YfwK3u5CngEcPihRQbcK1dxr1jIcXn3D06 8MJSQ912dDBslL/9gt/OtRlGb1ulAmOXXKWNM1Hm+2l/YbGCtPJkEdQkIlzhOn7c0mpe hk6/H2PeyP+WUsrPuZuFwkcy1lVb7XnErZmdInGACvGmPUOufUzEZ8NQ7S26rMb4J64o 5gwkLljoLS4NrblR8iZdpYPpU8AdeAWIWVei3ZTI96b1zdbKNleEAOzItRDZDGBR2N8q IT7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=v5caC1qoDQHmpMSdvWXR9hOq/bI0FBDMIPeurKroVVk=; b=AWWb9Aa8QjSswelULR+mL/ixhkdWw+gBJc6q1n/nTY8FHt1RhFoHjwaNcfi3JtrK96 U2uqKrmRE+v1dIqqlBkOdM3/YNBfeAj9+wHvu8EnbBIplEYe/eh2ThBAyQeLYmH6/FuT yQjtybWio4q9+ezvaz1MaUzZGbvjS/fe7LofQbsOyFU4V1ech/FjTTEJtmHFkKBdeLVt OmZuoDE/1nBBCSBYn1WopQkP04+dOTujq+mWn2mWdW/AGMi6geG0njjsIGt4fMFTkdyL RpiPOatAYi0rSAQWyiz4zJ/V92LNM5bzRwmKunNRGj5i6JPU5mCO7o2sPxIGkmfB4arI M2xQ== X-Gm-Message-State: AOAM5333L3zfCSQA/5yuATwSxk7cqnUC6vexeFZ2bWpJQioQYjuiKk39 bKMn9JroNgTMtgZcwdfNdn01xo7BSuPgRQVOPpk= X-Google-Smtp-Source: ABdhPJzTUjtarvR+lqTtZ+Rql9/M62aP+i0uM6QPAPlhB68Hk5MDMM5mygWfYfouMPaRJshbsIFl3E6Yq2HGIQxmhuw= X-Received: by 2002:a0c:8b99:: with SMTP id r25mr15465868qva.174.1590423346962; Mon, 25 May 2020 09:15:46 -0700 (PDT) MIME-Version: 1.0 References: <20200508163218.22592-1-lulu@redhat.com> <20200508163218.22592-6-lulu@redhat.com> <20200521124032.GH251811@stefanha-x1.localdomain> In-Reply-To: From: Stefan Hajnoczi Date: Mon, 25 May 2020 17:15:35 +0100 Message-ID: Subject: Re: [RFC v2 5/9] vhost-vdpa: implement vhost-vdpa backend To: Cindy Lu Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2607:f8b0:4864:20::f44; envelope-from=stefanha@gmail.com; helo=mail-qv1-xf44.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: rdunlap@infradead.org, Michael Tsirkin , mhabets@solarflare.com, qemu-devel , rob.miller@broadcom.com, saugatm@xilinx.com, Markus Armbruster , Christoph Hellwig , Eugenio Perez Martin , jgg@mellanox.com, Jason Wang , Shahaf Shuler , "Tian, Kevin" , parav@mellanox.com, vmireyno@marvell.com, "Liang, Cunming" , gdawar@xilinx.com, jiri@mellanox.com, "Wang, Xiao W" , Stefan Hajnoczi , "Wang, Zhihong" , Maxime Coquelin , Tiwei Bie , Ariel Adam , Cornelia Huck , hanand@xilinx.com, "Zhu, Lingshan" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, May 25, 2020 at 4:34 PM Cindy Lu wrote: > On Thu, May 21, 2020 at 8:40 PM Stefan Hajnoczi wrote: > > On Sat, May 09, 2020 at 12:32:14AM +0800, Cindy Lu wrote: > > > From: Tiwei Bie > > > > > > Currently we have 2 types of vhost backends in QEMU: vhost kernel and > > > vhost-user. The above patch provides a generic device for vDPA purpose, > > > this vDPA device exposes to user space a non-vendor-specific configuration > > > interface for setting up a vhost HW accelerator, this patch set introduces > > > a third vhost backend called vhost-vdpa based on the vDPA interface. > > > > > > Vhost-vdpa usage: > > > > > > qemu-system-x86_64 -cpu host -enable-kvm \ > > > ...... > > > -netdev type=vhost-vdpa,vhostdev=/dev/vhost-vdpa-id,id=vhost-vdpa0 \ > > > -device virtio-net-pci,netdev=vhost-vdpa0,page-per-vq=on \ > > > > I haven't looked at vDPA in depth. What is different here compared to > > the existing vhost-backend.c kernel backend? > > > > It seems to be making the same ioctls calls so I wonder if it makes > > sense to share the vhost-backend.c kernel code? > > > > Stefan > Hi Stefan, > Sorry for the late reply and Thanks for these suggestions. > I think the most difference between vhost kernel and vdpa is vdpa > depends on a real hardware. > The point is that vDPA devices work as a virtio device, but vhost-vdpa > qemu must present a vhost-like device in qemu vhost layer. > The ioctl calls are similar with vhost-backend.c now, but after more > and more NIC support vdpa. The difference between vhost-backend.c and > vpda will become more and more big. It will make the code complicated > to share the code with kernel code. Okay, thanks. Stefan