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 E0C8BC76196 for ; Mon, 3 Apr 2023 18:18:40 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pjOkW-0004yA-Re; Mon, 03 Apr 2023 14:17:48 -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 1pjOkV-0004xl-BP for qemu-devel@nongnu.org; Mon, 03 Apr 2023 14:17:47 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pjOkT-0005SA-UP for qemu-devel@nongnu.org; Mon, 03 Apr 2023 14:17:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680545864; 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=5uLE7zjqBICXjlH8JMOkaik6Yad+Dg1Q76bn45edDEQ=; b=ZP1FNTOtbRfi7EEpyi0RdYEVcXTKHU5XogYqyyPaGLSbNDvoB3JaHViYO2XZZrLgQX2ACx dMUTq3yecrcfEkSKtjDWFNoCC+x1xGR0ItuN/BluBzgX910wKynIKd8dG/qkHF3rRnh5uA itvLG4gDF4BD/lzqmatlz51psi5e5aw= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-53-wnbKu8TIO5iHpl_yUMN5ew-1; Mon, 03 Apr 2023 14:17:39 -0400 X-MC-Unique: wnbKu8TIO5iHpl_yUMN5ew-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 971803814587; Mon, 3 Apr 2023 18:17:38 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.52]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 65F6735453; Mon, 3 Apr 2023 18:17:38 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 6139C21E6926; Mon, 3 Apr 2023 20:17:37 +0200 (CEST) From: Markus Armbruster To: Thomas Huth Cc: Markus Armbruster , Alex =?utf-8?Q?Benn=C3=A9e?= , qemu-devel@nongnu.org, 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> <871ql1lc2z.fsf@pond.sub.org> <87mt3pm6tf.fsf@linaro.org> <871ql19fs4.fsf@pond.sub.org> <21d10332-f109-15aa-b282-bc31c07b364c@redhat.com> Date: Mon, 03 Apr 2023 20:17:37 +0200 In-Reply-To: <21d10332-f109-15aa-b282-bc31c07b364c@redhat.com> (Thomas Huth's message of "Mon, 3 Apr 2023 18:31:04 +0200") Message-ID: <875yac4ypq.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 10.11.54.5 Received-SPF: pass client-ip=170.10.129.124; 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 Thomas Huth writes: > On 03/04/2023 16.55, Markus Armbruster wrote: >> Alex Benn=C3=A9e writes: >>=20 >>> Markus Armbruster writes: >>> >>>> Alex Benn=C3=A9e writes: > ... >>> I was under the impression things like -hda wouldn't work say on an Arm >>> machine because you don't know what sort of interface you might be >>> using and -hda implies IDE. Where is this macro substitution done? >>=20 >> qemu_init() calls drive_add() for all these options. >>=20 >> drive_add(TYPE, INDEX, FILE, OPTSTR) creates a QemuOpts in group >> "drive". It sets "if" to if_name[TYPE] unless TYPE is IF_DEFAULT, >> "index" to INDEX unless it's negative, and "file" to FILE unless it's >> null. Then it parses OPTSTR on top. >>=20 >> For -hdX, the call looks like >>=20 >> drive_add(IF_DEFAULT, popt->index - QEMU_OPTION_hda, op= targ, >> HD_OPTS); >>=20 >> We pass IF_DEFAULT, so "if" remains unset. "index" is set to 0 for >> -hda, 1, for -hdb and so forth. "file" is set to the option argument. >> Since HD_OPTS is "media=3Ddisk", we set "media" to "disk". >>=20 >> The QemuOpts in config group "drive" get passed to drive_new() via >> drive_init_func(). Unset "if" defaults to the current machine's class's >> block_default_type. >>=20 >> If a machine doesn't set this member explicitly, it remains zero, which >> is IF_NONE. Documented in blockdev.h: >>=20 >> typedef enum { >> IF_DEFAULT =3D -1, /* for use with drive_add() only = */ >> /* >> * IF_NONE must be zero, because we want MachineClass member >> ---> * block_default_type to default-initialize to IF_NONE >> */ >> IF_NONE =3D 0, >> IF_IDE, IF_SCSI, IF_FLOPPY, IF_PFLASH, IF_MTD, IF_SD, IF_VIRTIO= , IF_XEN, >> IF_COUNT >> } BlockInterfaceType; >>=20 >> Questions? > > How's the average user supposed to know that? Our qemu-options.hx just sa= ys:=20 > "-hda/-hdb file use 'file' as IDE hard disk 0/1 image"... Ancient doc bug. Should have been updated in commit 2d0d2837dcf (Support default block interfaces per QEMUMachine) back in 2012.