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 E6698C761A6 for ; Mon, 3 Apr 2023 06:23:17 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pjDaJ-0007I8-6s; Mon, 03 Apr 2023 02:22:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pjDaE-0007Fn-2m for qemu-devel@nongnu.org; Mon, 03 Apr 2023 02:22:27 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pjDaB-0000zy-0v for qemu-devel@nongnu.org; Mon, 03 Apr 2023 02:22:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680502939; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=7Ke0XOLjHyP51AZrx6au9pHWRsLphMBn4QLOm46d90k=; b=aLruUzYi35UEtgoVBuslYLnZaOsoVJj0B7D6a5gtoZjy3gtz5rbCZyvSpA8COmQX+70eKZ 2vZ5n74zHRFrHRO6h1IuMT8wVNMBOXBWhEYrh+TyJAxLyBF7qZQNNmftHSk2v3eFNNbPKo kusldfJ0Tv4bkGFOyItOe/VJnZfV3jE= 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-486-qz1yvOKfM3ebFQxxURVUQw-1; Mon, 03 Apr 2023 02:22:16 -0400 X-MC-Unique: qz1yvOKfM3ebFQxxURVUQw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 83D85858289; Mon, 3 Apr 2023 06:22:15 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.52]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C67741415117; Mon, 3 Apr 2023 06:22:13 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 8FC7321E6926; Mon, 3 Apr 2023 08:22:12 +0200 (CEST) From: Markus Armbruster To: Alex =?utf-8?Q?Benn=C3=A9e?= Cc: qemu-devel@nongnu.org, Thomas Huth , Warner Losh , Ryo ONODERA , Kevin Wolf , Beraldo Leal , Wainer dos Santos Moschetta , Hanna Reitz , qemu-block@nongnu.org, Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Kyle Evans , Reinoud Zandijk , Michael Tokarev Subject: Re: [PATCH 04/11] qemu-options: finesse the recommendations around -blockdev References: <20230330101141.30199-1-alex.bennee@linaro.org> <20230330101141.30199-5-alex.bennee@linaro.org> Date: Mon, 03 Apr 2023 08:22:12 +0200 In-Reply-To: <20230330101141.30199-5-alex.bennee@linaro.org> ("Alex =?utf-8?Q?Benn=C3=A9e=22's?= message of "Thu, 30 Mar 2023 11:11:34 +0100") Message-ID: <871ql1lc2z.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com 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, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, 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: 2.1.29 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-bounces+qemu-devel=archiver.kernel.org@nongnu.org Alex Benn=C3=A9e writes: > We are a bit premature in recommending -blockdev/-device as the best > way to configure block devices, especially in the common case. > Improve the language to hopefully make things clearer. > > Suggested-by: Michael Tokarev > Signed-off-by: Alex Benn=C3=A9e > --- > qemu-options.hx | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/qemu-options.hx b/qemu-options.hx > index 59bdf67a2c..9a69ed838e 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -1143,10 +1143,14 @@ have gone through several iterations as the featu= re set and complexity > of the block layer have grown. Many online guides to QEMU often > reference older and deprecated options, which can lead to confusion. >=20=20 > -The recommended modern way to describe disks is to use a combination of > +The most explicit way to describe disks is to use a combination of > ``-device`` to specify the hardware device and ``-blockdev`` to > describe the backend. The device defines what the guest sees and the > -backend describes how QEMU handles the data. > +backend describes how QEMU handles the data. The ``-drive`` option > +combines the device and backend into a single command line options > +which is useful in the majority of cases. -drive may look simpler from afar, but it really is a hot mess. Sadly, we can't get rid of it until we find a replacement for configuring onboard block devices. We might be able to clean it up some if we accept compatibility breaks. A new convenience option would be less confusing, I guess. > Older options like ``-hda`` > +bake in a lot of assumptions from the days when QEMU was emulating a > +legacy PC, they are not recommended for modern configurations. >=20=20 > ERST These older options and the non-option argument are simple macros for -drive: IMG-FILE -drive index=3D0,file=3DIMG-FILE,media=3Ddi= sk -hda IMG-FILE -drive index=3D0,file=3DIMG-FILE,media=3Ddi= sk -hdb IMG-FILE -drive index=3D1,file=3DIMG-FILE,media=3Ddi= sk -hdc IMG-FILE -drive index=3D2,file=3DIMG-FILE,media=3Ddi= sk -hdd IMG-FILE -drive index=3D3,file=3DIMG-FILE,media=3Ddi= sk -cdrom IMG-FILE -drive index=3D2,file=3DIMG-FILE,media=3Dcd= rom -fda IMG-FILE -drive if=3Dfloppy,index=3D0,file=3DIMG-FILE -fdb IMG-FILE -drive if=3Dfloppy,index=3D1,file=3DIMG-FILE -mtdblock IMG-FILE -drive if=3Dmtd,file=3DIMG-FILE -sd IMG-FILE -drive if=3Dsd,file=3DIMG-FILE -pflash IMG-FILE -drive if=3Dpflash,file=3DIMG-FILE What assumptions do you have in mind? I think you need at least Kevin's Acked-by for this.