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 96807C6FD1A for ; Mon, 6 Mar 2023 18:37:42 +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 C9CBD76068 for ; Mon, 6 Mar 2023 18:37:41 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id BE2AF9866C4 for ; Mon, 6 Mar 2023 18:37:41 +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 B24479866BD; Mon, 6 Mar 2023 18:37:41 +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 A24799866BF for ; Mon, 6 Mar 2023 18:37:41 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: R_XI--CEOOGR_0Kg_oMfSQ-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678127856; 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=fUWErxNPrUrIMv2QbGRSFvzl2G28V2kvcbsO7YO7Kg0=; b=3vTiEPTr0NNEivoISNHRq0yeMTdqXsK+x4aGyb4WLvHacC3XNLIZTCViMCtQtALdBu jqB+R+GV2E5jg4xPFhuYw6+ce2E2LxjZK6d+BnyfWgcKOVtRIjGrWOEqxOqb81qnWKzC jSMEWUv+7YNzOEEH7NPpGyXlnNAuMrk7X46V+CKjvQAWQpeC4iIazbjwTFmY1XsW1+Zv EwyOqsIDbYZe4Ggagr29YGlCctAvE8x2f1nlk8JZBmhaIwYolGSDBNM0nqtDAVZ6OjWc Ia6wTmAudeq39Dx8oZ/AD1JPUfP7mhgSPzWv3QwRmU14b4c6CXvZubWRHuCgPbpdFDjz 2s7Q== X-Gm-Message-State: AO0yUKVH4L+En0D8HcHpQvtkbDh2vht4p6U6l1XfLybafVxyjPyXlIt0 DN6S+iYrPvQGD56PX887z/pD44MC7RRnPNhhvElT4zQ2ayQ+aKr97dSG3nGjPwueEg4umVHFGmM 7QtuYWsV8Ex1UIMZG0Crp0LzeF1Bb X-Received: by 2002:a05:600c:3b0c:b0:3eb:2b88:999f with SMTP id m12-20020a05600c3b0c00b003eb2b88999fmr9887596wms.5.1678127856112; Mon, 06 Mar 2023 10:37:36 -0800 (PST) X-Google-Smtp-Source: AK7set+pfueUoTftA7cCbkxlmh7uF0V/CpSd6IjoWMj0zckWOgYt3Z+Ok+5HFp4Hrghly0Ye4rD4WA== X-Received: by 2002:a05:600c:3b0c:b0:3eb:2b88:999f with SMTP id m12-20020a05600c3b0c00b003eb2b88999fmr9887577wms.5.1678127855839; Mon, 06 Mar 2023 10:37:35 -0800 (PST) Date: Mon, 6 Mar 2023 13:37:31 -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: <20230306133525-mutt-send-email-mst@kernel.org> References: <20c81b66f0b21b5bd646c24840ac3f8462c86acf.1677761896.git.mst@redhat.com> <20230302204007.GD2554028@fedora> <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> MIME-Version: 1.0 In-Reply-To: <20230306110340.GA35392@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 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". -- MST --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org