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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 4CDD3C04A68 for ; Wed, 27 Jul 2022 19:38:39 +0000 (UTC) Received: from localhost ([::1]:56230 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oGmre-0001Sc-96 for qemu-devel@archiver.kernel.org; Wed, 27 Jul 2022 15:38:38 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56480) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oGmn7-0006hO-4f for qemu-devel@nongnu.org; Wed, 27 Jul 2022 15:33:57 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:29337) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oGmn0-0000ay-OD for qemu-devel@nongnu.org; Wed, 27 Jul 2022 15:33:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1658950429; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=F8aG+xqlg7S7qrggqrYU2k+A00Sb6LEOAkj2nCO300U=; b=EBM77IKxp0ioZN4sCcKiUx/T8UlzcwD0YMOmVMF1KIL4zbo7r0RJX6/tWhJdL/fffKDRvv 2e2abGkAjrdULlpokyEV49kW9NXXs1lp2/Zl1V2ovj5uH/rD8MSWRzcajZoRMN1kFAKMO+ bx4V3Fwxa1/IfMY22oQLMiqGWYCEicI= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-449-YgWvMHJ9M_Orn0rWpMs3Qw-1; Wed, 27 Jul 2022 15:33:46 -0400 X-MC-Unique: YgWvMHJ9M_Orn0rWpMs3Qw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E0927101A54E; Wed, 27 Jul 2022 19:33:45 +0000 (UTC) Received: from redhat.com (unknown [10.39.193.209]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4149B40CFD0A; Wed, 27 Jul 2022 19:33:42 +0000 (UTC) Date: Wed, 27 Jul 2022 21:33:40 +0200 From: Kevin Wolf To: Stefan Hajnoczi Cc: qemu-devel@nongnu.org, Alberto Faria , Vladimir Sementsov-Ogievskiy , "Michael S. Tsirkin" , Paolo Bonzini , Laurent Vivier , Eric Blake , sgarzare@redhat.com, Marcel Apfelbaum , Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= , qemu-block@nongnu.org, Eduardo Habkost , Vladimir Sementsov-Ogievskiy , John Snow , Thomas Huth , Markus Armbruster , Hanna Reitz , Fam Zheng , Yanan Wang , pkrempa@redhat.com Subject: Re: [RFC v3 1/8] blkio: add io_uring block driver using libblkio Message-ID: References: <20220708041737.1768521-1-stefanha@redhat.com> <20220708041737.1768521-2-stefanha@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220708041737.1768521-2-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 Received-SPF: pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 08.07.2022 um 06:17 hat Stefan Hajnoczi geschrieben: > libblkio (https://gitlab.com/libblkio/libblkio/) is a library for > high-performance disk I/O. It currently supports io_uring and > virtio-blk-vhost-vdpa with additional drivers under development. > > One of the reasons for developing libblkio is that other applications > besides QEMU can use it. This will be particularly useful for > vhost-user-blk which applications may wish to use for connecting to > qemu-storage-daemon. > > libblkio also gives us an opportunity to develop in Rust behind a C API > that is easy to consume from QEMU. > > This commit adds io_uring and virtio-blk-vhost-vdpa BlockDrivers to QEMU > using libblkio. It will be easy to add other libblkio drivers since they > will share the majority of code. > > For now I/O buffers are copied through bounce buffers if the libblkio > driver requires it. Later commits add an optimization for > pre-registering guest RAM to avoid bounce buffers. > > The syntax is: > > --blockdev io_uring,node-name=drive0,filename=test.img,readonly=on|off,cache.direct=on|off > > and: > > --blockdev virtio-blk-vhost-vdpa,node-name=drive0,path=/dev/vdpa...,readonly=on|off > > Signed-off-by: Stefan Hajnoczi The subject line implies only io_uring, but you actually add vhost-vdpa support, too. I think the subject line should be changed. I think it would also make sense to already implement support for vhost-user-blk on the QEMU side even if support isn't compiled in libblkio by default and opening vhost-user-blk images would therefore always fail with a default build. But then you could run QEMU with a custom build of libblkio to make use of it without patching QEMU. This is probably useful for getting libvirt support for using a storage daemon implemented without having to wait for another QEMU release. (Peter, do you have any opinion on this?) Kevin