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 35601C61DA4 for ; Sat, 18 Mar 2023 12:42:51 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pdVtE-0005dj-PT; Sat, 18 Mar 2023 08:42:28 -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 1pdVtD-0005dT-Mo for qemu-devel@nongnu.org; Sat, 18 Mar 2023 08:42:27 -0400 Received: from mail-wm1-x32c.google.com ([2a00:1450:4864:20::32c]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1pdVtB-0002tl-B9 for qemu-devel@nongnu.org; Sat, 18 Mar 2023 08:42:27 -0400 Received: by mail-wm1-x32c.google.com with SMTP id fm20-20020a05600c0c1400b003ead37e6588so6529355wmb.5 for ; Sat, 18 Mar 2023 05:42:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1679143343; h=content-transfer-encoding:mime-version:message-id:in-reply-to:date :subject:cc:to:from:user-agent:references:from:to:cc:subject:date :message-id:reply-to; bh=+X5AZjW4T3hafnEKWm40v+WXiEjKiog1S2u4reHJTF8=; b=NZ8E9SQYeAxJ7u+dI7gRE1UidZX0tTBk/ga6QI0h3hsrtccqqWdanc+p212OPM5FKU J6nATdWRcPLo9vk1HeE6BtsSI1dyup/HiBCaG3HWgshxPsDve4nzvpFJa6bTvVj8UcEc iKUylYOvnMajR1sKXucUPdt+iNyQL32SQMzENeEe1B6hEGqYnMiIhkN1oUH/o3atrllK Xc7GGReIjnaZ6t0a67zD5cl5zzZ43P22yMnyD+zpOpigAgA0Amcy5fjCvxIOaMGNZA9n fXVu4+DeMi8ShUfb1mf3E/Ey6GP+cxP5OZ/N4cO2CNBFCdDUfN78d6KFRH6ynvqjeM3r bi+A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679143343; h=content-transfer-encoding:mime-version:message-id:in-reply-to:date :subject:cc:to:from:user-agent:references:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=+X5AZjW4T3hafnEKWm40v+WXiEjKiog1S2u4reHJTF8=; b=ATtFD+gsi22PBf4999rPZaZpRB6OERLoCtRIDz0NAJS05K6QDL2QCl8/LSOL2DBwm7 ohWMiO53Gr7q/yHtEv49KUCDTN2RetXzVh/NPQsftAk6xuSlaKWQc3eIRRhs5A8gSQNF uHrF/a+5yrYGKxRsrGbZyM14/eqKanwPUJIxQMWlraMp6vfA/d6cfCrNcbydJd5L5oEI SK5+qG0cLtBagZ1wc+cpw5vULmib6ZWrGbb24NKDe4EjRp4Js3FGa/RtvZNg+d/aMtiF nNReJ3NHfvHMxi4q123KkQbbs9QelYJyKPd/7CgW37QSdKHiB/BbmMn6zLlN/W0PovKV e7Ng== X-Gm-Message-State: AO0yUKVMKjSmXZAdSbrE27Sltoy3jzuCPVdYLhxd+gB2irQI/d1uJ5gb wegw70Ol4gl3ODJNmk0cYTsFZw== X-Google-Smtp-Source: AK7set/qPkqD2vXp4Q7GK0IhYVl820fQ3a5Gnm6J7n+Pmji8BOt/VMGhnFfKdY3lL1KMhWy1TS2IIw== X-Received: by 2002:a05:600c:21c6:b0:3ed:775e:5257 with SMTP id x6-20020a05600c21c600b003ed775e5257mr5094552wmj.35.1679143343029; Sat, 18 Mar 2023 05:42:23 -0700 (PDT) Received: from zen.linaroharston ([85.9.250.243]) by smtp.gmail.com with ESMTPSA id k2-20020a5d6e82000000b002c55b0e6ef1sm4337428wrz.4.2023.03.18.05.42.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 18 Mar 2023 05:42:22 -0700 (PDT) Received: from zen (localhost [127.0.0.1]) by zen.linaroharston (Postfix) with ESMTP id 666CA1FFB7; Sat, 18 Mar 2023 12:42:22 +0000 (GMT) References: <20230318075159.97849-1-mjt@msgid.tls.msk.ru> User-agent: mu4e 1.9.22; emacs 29.0.60 From: Alex =?utf-8?Q?Benn=C3=A9e?= To: Michael Tokarev Cc: qemu-block@nongnu.org, stefanha@redhat.com, qemu-devel@nongnu.org Subject: Re: [PATCH] doc: do not recommend -blockdev Date: Sat, 18 Mar 2023 12:32:13 +0000 In-reply-to: <20230318075159.97849-1-mjt@msgid.tls.msk.ru> Message-ID: <874jqiw7rl.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2a00:1450:4864:20::32c; envelope-from=alex.bennee@linaro.org; helo=mail-wm1-x32c.google.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, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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-bounces+qemu-devel=archiver.kernel.org@nongnu.org Michael Tokarev writes: > Currently, documentation recommends to use -blockdev instead of -drive. > This is quite a bit misleading, because -blockdev is "too" low-level, > requires good knowlege of how to construct block device stack, esp. > in context of various qcow2 layers, and requires too explicit configurati= on. > More, quite some constructs does not work with -blockdev, - for example > this is -snapshot. > > Instead of "recommended" word, use another construct here. Could we expand the images section: https://qemu.readthedocs.io/en/latest/system/images.html to give a better overview of when you should use -device/-blockdev vs -driv= e? > > Signed-off-by: Michael Tokarev > --- > qemu-options.hx | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/qemu-options.hx b/qemu-options.hx > index 59bdf67a2c..8fe31b465d 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -1143,7 +1143,7 @@ have gone through several iterations as the feature= 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 low-level detailed 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. How about: 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. The ``--drive`` option combines the device and backend into a single command line options which is useful in the majority of cases. Older options like ``-hda`` make a bake in a lot of assumptions from the days when QEMU was emulating a legacy PC, they are not recommended for modern configurations. --=20 Alex Benn=C3=A9e Virtualisation Tech Lead @ Linaro