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=-4.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 1574DC433E9 for ; Thu, 3 Sep 2020 11:06:19 +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 60CBF20767 for ; Thu, 3 Sep 2020 11:06:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=crudebyte.com header.i=@crudebyte.com header.b="I2cRl3Ij" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 60CBF20767 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=crudebyte.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:48678 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kDn4L-0003Vk-8g for qemu-devel@archiver.kernel.org; Thu, 03 Sep 2020 07:06:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59538) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kDmvW-0004Pk-PV for qemu-devel@nongnu.org; Thu, 03 Sep 2020 06:57:10 -0400 Received: from lizzy.crudebyte.com ([91.194.90.13]:48207) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kDmvU-0004dF-Fl for qemu-devel@nongnu.org; Thu, 03 Sep 2020 06:57:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=crudebyte.com; s=lizzy; h=Content-Type:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Content-ID:Content-Description; bh=W/2lkrRkIyBo/QVdv7kuUCGeweBZ0qZUPsBVLhIU7Vg=; b=I2cRl3IjOZ3E5y5FR/t1vl/cHh 7hH/bfsONFMNctI2o2QQt90ipIYmer10owbeVXEXieHrUU9U2AS2WsuMZM0YpChwUnjj22OYlvul+ i+zy8oUWtXV8gUoCwDDZ1Qs5P6dxknVbvT16VZM8VlouhY0K7kww3uqjP4H1txwS3zN/butb/uBlh 9qGpM7JjTqOoJ+H5fCjCHBDUOk2wKr9FWtHlQZr0Y18Xq9y1nSNXlwIzoaBeiTn0MAzy3txvuMUhZ YnXrO/MPs5fR8x0L62oYoz5bU9kVNNP0hdPAwxtZqVKSGrxs9os1x5OVbZXKqx6FsPd6o+pQ4pGhn R9SPqNig==; From: Christian Schoenebeck To: qemu-devel@nongnu.org Cc: Greg Kurz , Daniel =?ISO-8859-1?Q?P=2E_Berrang=E9?= Subject: Re: [PATCH] 9pfs: log warning if msize <= 8192 Date: Thu, 03 Sep 2020 12:57:04 +0200 Message-ID: <5477909.c10NYOVa74@silver> In-Reply-To: <20200903113514.7a0a6ac8@bahia.lan> References: <25793713.39nqsFcaVY@silver> <20200903113514.7a0a6ac8@bahia.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Received-SPF: pass client-ip=91.194.90.13; envelope-from=qemu_oss@crudebyte.com; helo=lizzy.crudebyte.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/03 06:57:06 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] 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, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Donnerstag, 3. September 2020 11:35:14 CEST Greg Kurz wrote: > > On the long term that would be possible, however only with a protocol > > change allowing server to send minimum, maximum and recommended msize to > > client. > Hmm... not sure adding a new 9P protocol version for this is the > way to go. Not speaking of all the hustle this would cause, these > msizes rather look like properties of the device that the guest > can use to configure the 9P session. > > What about adding them to the virtio-9p device config along with > the mount 'tag' and teach trans_virtio.c in linux to expose them > as well in the sysfs entry of the device ? > > This could also be the occasion to describe virtio-9p in the virtio > spec [1]. Something that has been sitting on my TODO list for years > but I could never find time to consider... > > [1] https://docs.oasis-open.org/virtio/virtio/v1.1/virtio-v1.1.html Sounds like a good idea! > > As you know, right now server only has a say in maximum msize. > > I guess you mean minimum size ? Well, it's ambiguous, but we mean the same thing: server may optionally lower the msize previously suggested by client; server must not raise client's suggested msize though. If you see it in the context of Rversion response handling then that's a "minimum" operation, yes. If you see it as prose then it is "maximum msize", e.g.: Server's max. supported msize: 20 MiB <- covered by 9P protocol Server's min. supported msize: 4 kiB <- not officially covered by 9P Client suggests msize 100 MiB -> server lowers that to min(100MiB, 20MiB) = 20MiB. Best regards, Christian Schoenebeck