From nobody Fri May 17 09:18:35 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1571400247; cv=none; d=zoho.com; s=zohoarc; b=lmIb1UgtRwNtvuB6R0s3Oc+NhdErvhNNyX73Z7kzUvBMpkdu5uxkZICHaNKGS1tp7757rAIgYCp3QaaDKEa/NRVPNeP42/sArMMuuoquMlIP3EaOPHA6fF/rRQnCY4b2UNFpN2worT3PB84muIPe3ER2qtB6UpBBmY0PQSNoG70= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1571400247; h=Content-Transfer-Encoding:Cc:Date:From:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Sender:Subject:To; bh=Wqb5bk5HZF+Y64P7S2JZPw2ngv/ltZRktMYVmMddlws=; b=D9GMyo6GC1zTXaUGb0S8SWyDF6k7Jd3uW0gbWLAUFgnbfDbir8hiBk+KZe8d/OLXMc4taFJaTuIJNuMC/Ii3dkHoz5pWEGn/RCcw+4FbkmHJfzc6J0nSlVTMjx0RW4Lg5qEYZZJl3natvkluNcZ/ywBVejppF8PxHYyevjh3wkI= ARC-Authentication-Results: i=1; mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 15714002473441005.987101561026; Fri, 18 Oct 2019 05:04:07 -0700 (PDT) Received: from localhost ([::1]:38934 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iLQzC-0001Ll-Ae for importer@patchew.org; Fri, 18 Oct 2019 08:04:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38136) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iLQy8-0000WH-Gr for qemu-devel@nongnu.org; Fri, 18 Oct 2019 08:02:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iLQy7-0006oh-77 for qemu-devel@nongnu.org; Fri, 18 Oct 2019 08:02:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40238) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iLQxz-0006di-JL; Fri, 18 Oct 2019 08:02:47 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D5FF0A76C; Fri, 18 Oct 2019 12:02:46 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-117-198.ams2.redhat.com [10.36.117.198]) by smtp.corp.redhat.com (Postfix) with ESMTP id 892CC1001B03; Fri, 18 Oct 2019 12:02:45 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PATCH v2] doc: Describe missing generic -blockdev options Date: Fri, 18 Oct 2019 14:02:35 +0200 Message-Id: <20191018120235.4438-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Fri, 18 Oct 2019 12:02:46 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 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: , Cc: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" We added more generic options after introducing -blockdev and forgot to update the documentation (man page and --help output) accordingly. Do that now. Signed-off-by: Kevin Wolf Reviewed-by: Peter Maydell --- qemu-options.hx | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/qemu-options.hx b/qemu-options.hx index 793d70ff93..2e6ba5ef1f 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -849,7 +849,8 @@ ETEXI DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, "-blockdev [driver=3D]driver[,node-name=3DN][,discard=3Dignore|unmap]\= n" " [,cache.direct=3Don|off][,cache.no-flush=3Don|off]\n" - " [,read-only=3Don|off][,detect-zeroes=3Don|off|unmap]\n" + " [,read-only=3Don|off][,auto-read-only=3Don|off]\n" + " [,force-share=3Don|off][,detect-zeroes=3Don|off|unmap]\n" " [,driver specific parameters...]\n" " configure a block backend\n", QEMU_ARCH_ALL) STEXI @@ -885,6 +886,25 @@ name is not intended to be predictable and changes bet= ween QEMU invocations. For the top level, an explicit node name must be specified. @item read-only Open the node read-only. Guest write attempts will fail. + +Note that some block drivers support only read-only access, either general= ly or +in certain configurations. In this case, the default value +@option{read-only=3Doff} does not work and the option must be specified +explicitly. +@item auto-read-only +If @option{auto-read-only=3Don} is set, QEMU may fall back to read-only us= age +even when @option{read-only=3Doff} is requested, or even switch between mo= des as +needed, e.g. depending on whether the image file is writable or whether a +writing user is attached to the node. +@item force-share +Override the image locking system of QEMU by forcing the node to utilize +weaker shared access for permissions where it would normally request exclu= sive +access. When there is the potential for multiple instances to have the sa= me +file open (whether this invocation of qemu is the first or the second +instance), both instances must permit shared access for the second instanc= e to +succeed at opening the file. + +Enabling @option{force-share=3Don} requires @option{read-only=3Don}. @item cache.direct The host page cache can be avoided with @option{cache.direct=3Don}. This w= ill attempt to do disk IO directly to the guest's memory. QEMU may still perfo= rm an --=20 2.20.1