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 ws5-mx01.kavi.com (ws5-mx01.kavi.com [34.193.7.191]) (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 D5B7BC64EC4 for ; Mon, 6 Mar 2023 21:44:09 +0000 (UTC) Received: from lists.oasis-open.org (oasis.ws5.connectedcommunity.org [10.110.1.242]) by ws5-mx01.kavi.com (Postfix) with ESMTP id D42341318C2 for ; Mon, 6 Mar 2023 21:44:08 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id BEE7B9866C9 for ; Mon, 6 Mar 2023 21:44:08 +0000 (UTC) Received: from host09.ws5.connectedcommunity.org (host09.ws5.connectedcommunity.org [10.110.1.97]) by lists.oasis-open.org (Postfix) with QMQP id B0016983C2D; Mon, 6 Mar 2023 21:44:08 +0000 (UTC) Mailing-List: contact virtio-dev-help@lists.oasis-open.org; run by ezmlm List-ID: Sender: Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 9AD739866C1 for ; Mon, 6 Mar 2023 21:44:04 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: may8pab_MYKc-5YQD9lU9g-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678139041; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=/OY/rntB86FytA/6O5zjv5r2vzqTbNde/PGe0CGx4/w=; b=mI7+AW+79X7g2r87kpGHXSxAgqQsMiqXOh+JBE4/dsxvXFb+NHQa/IbFWhRXKNqqDS wWiF2R8c+r1R9rYcwMexeS/YAYgAXtufprIbypRiuFuFOvoemaijbfkCke2bKK4+ytTe RibokaaZgnv5sAckLVmT4Veqw0C6G2wAa9tdYuKAMr3noQGxN/vz/grc6iJm0qJn154l wJE5v/eSzjR4uJAfokQw4af6/LPDlncPkbI1YVDT8bdDuj9hD86BjT2VPZfjZ4pDq5Xs GsepGKYidelHHD9iK2TgsDVFij4YJ0Z6jJkOIP15y3S4eSAx1vxt/hie5vQVC3C2qjk9 88Lw== X-Gm-Message-State: AO0yUKUbgOy0vcszLFDoj+m11EBMsoOm6ukHiM1+2TC4i0q9zITP10oC VWAQK2Z7e3i/+uc6TugrG6fgY0MXfi9hfVyEGPOthU3ajPqj267KgowU9hwSPGrwLIu1rMwI+Z8 CZLCkH2r/xReHtdZa5kqfvDPRO2AO X-Received: by 2002:a5d:4ac6:0:b0:2c5:4ca3:d56c with SMTP id y6-20020a5d4ac6000000b002c54ca3d56cmr11301192wrs.0.1678139041297; Mon, 06 Mar 2023 13:44:01 -0800 (PST) X-Google-Smtp-Source: AK7set9SY3iOgrw3AyFW7DWcKjQr4SHvayzBNTWamAOSIOOPgDzdmCg5DkDyR4mjrnKDxoHWzX4sBg== X-Received: by 2002:a5d:4ac6:0:b0:2c5:4ca3:d56c with SMTP id y6-20020a5d4ac6000000b002c54ca3d56cmr11301176wrs.0.1678139040976; Mon, 06 Mar 2023 13:44:00 -0800 (PST) Date: Mon, 6 Mar 2023 16:43:55 -0500 From: "Michael S. Tsirkin" To: Stefan Hajnoczi Cc: virtio-comment@lists.oasis-open.org, virtio-dev@lists.oasis-open.org, jasowang@redhat.com, cohuck@redhat.com, sgarzare@redhat.com, nrupal.jani@intel.com, Piotr.Uminski@intel.com, hang.yuan@intel.com, virtio@lists.oasis-open.org, Zhu Lingshan , pasic@linux.ibm.com, Shahaf Shuler , Parav Pandit , Max Gurtovoy Message-ID: <20230306163955-mutt-send-email-mst@kernel.org> References: <20230302190230-mutt-send-email-mst@kernel.org> <20230303132840.GC2866370@fedora> <20230303083213-mutt-send-email-mst@kernel.org> <20230303202133.GA2901137@fedora> <20230305043419-mutt-send-email-mst@kernel.org> <20230306000302.GA244754@fedora> <20230305191351-mutt-send-email-mst@kernel.org> <20230306110340.GA35392@fedora> <20230306133525-mutt-send-email-mst@kernel.org> <20230306201759.GA78491@fedora> MIME-Version: 1.0 In-Reply-To: <20230306201759.GA78491@fedora> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Subject: [virtio-dev] Re: [virtio] Re: [PATCH v10 04/10] admin: introduce virtio admin virtqueues On Mon, Mar 06, 2023 at 03:17:59PM -0500, Stefan Hajnoczi wrote: > On Mon, Mar 06, 2023 at 01:37:31PM -0500, Michael S. Tsirkin wrote: > > On Mon, Mar 06, 2023 at 06:03:40AM -0500, Stefan Hajnoczi wrote: > > > On Sun, Mar 05, 2023 at 07:18:24PM -0500, Michael S. Tsirkin wrote: > > > > On Sun, Mar 05, 2023 at 07:03:02PM -0500, Stefan Hajnoczi wrote: > > > > > On Sun, Mar 05, 2023 at 04:38:59AM -0500, Michael S. Tsirkin wrote: > > > > > > On Fri, Mar 03, 2023 at 03:21:33PM -0500, Stefan Hajnoczi wrote: > > > > > > > What happens if a command takes 1 second to complete, is the device > > > > > > > allowed to process the next command from the virtqueue during this time, > > > > > > > possibly completing it before the first command? > > > > > > > > > > > > > > This requires additional clarification in the spec because "they are > > > > > > > processed by the device in the order in which they are queued" does not > > > > > > > explain whether commands block the virtqueue (in order completion) or > > > > > > > not (out of order completion). > > > > > > > > > > > > Oh I begin to see. Hmm how does e.g. virtio scsi handle this? > > > > > > > > > > virtio-scsi, virtio-blk, and NVMe requests may complete out of order. > > > > > Several may be processed by the device at the same time. > > > > > > > > Let's say I submit a write followed by read - is read > > > > guaranteed to return an up to date info? > > > > > > In general, no. The driver must wait for the write completion before > > > submitting the read if it wants consistency. > > > > > > Stefan > > > > I see. I think it's a good design to follow then. > > > > I'll just copy > > The driver queues requests to an arbitrary request queue, and > > they are used by the device on that same queue. It is the > > responsibility of the driver to ensure strict request ordering > > for commands placed on different queues, because they will be > > consumed with no order constraints. > > > > replacing "request" with "admin". > > That sounds like it's only about multi-queue because it says "... for > commands placed on different queues". What I mentioned about a write > followed by a read quest also applies within a single queue. Well that text is from the virtio scsi spec. turning it around does it need clarification there? > Can you clarify the semantics in the single queue case? > > Stefan --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org