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=-15.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 23B2DC433E0 for ; Thu, 14 Jan 2021 19:40:26 +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 C32A22343B for ; Thu, 14 Jan 2021 19:40:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C32A22343B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:55156 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l08To-0003RT-PF for qemu-devel@archiver.kernel.org; Thu, 14 Jan 2021 14:40:24 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:44600) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l08Rh-0002Jx-SL for qemu-devel@nongnu.org; Thu, 14 Jan 2021 14:38:13 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:33706) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l08Rf-0007sw-Rf for qemu-devel@nongnu.org; Thu, 14 Jan 2021 14:38:13 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1610653090; 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=gJWa34xrqF6QuTqeROtO7elVavrhMnJHwGEc4V0AkZ8=; b=i76A1+rc8F9djBHD2AqOmoNBjYxLDQ/fX9iuxbdwMCJLV9LWKVBZvQp7a/iVzgQi3saRod K0F9+sSU4JqReMOKgU0l0JxGzAk8r5xqlHXbKLoHSgZLK4K8rImm1tG3oqoWqwNdw3mEZi eTHn4mgUAGH03eV47AhqffQ6OollRYE= Received: from mail-ej1-f70.google.com (mail-ej1-f70.google.com [209.85.218.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-100-6npENWTJPzWfAXsHrJKEsw-1; Thu, 14 Jan 2021 14:38:06 -0500 X-MC-Unique: 6npENWTJPzWfAXsHrJKEsw-1 Received: by mail-ej1-f70.google.com with SMTP id u25so2647509ejf.3 for ; Thu, 14 Jan 2021 11:38:06 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=gJWa34xrqF6QuTqeROtO7elVavrhMnJHwGEc4V0AkZ8=; b=YcmzXJ+0oAxkUKtwTKwRnQZgCK+UAZUXKfJfWwhfXLaNvw351Q/86Iz/TZobdkWtSL oO8Td6S1R+SHAcCcrfW0RDmrdqbo0Ra5KLLHjyWvCZupI4FtJOpJU76v+OTo/szgJ7Vs toafggRa14vvhnvK6c+ChDSIdsJnbQdIEZPxnL6vN9Tmh625S+byVHj3fbKcgmHPTiVf shyRB1i8REJBhaXPERdwczAo3pO4PQ8qAie2mtsByDSgb3Wu9IRCJJCOXbeT52rRvUD3 a6OiF1FIZA7dZUBQ7TUiYcbwRJUD67t8OBBCxUCpxbHK596aT39uS3gRHWTYnyQ5+oB7 MH0g== X-Gm-Message-State: AOAM530EK+dq4obvG2jqWbq37ZX/EHAMQoxr+wLGRFIjMp79FL1whfgq 2GGjPIS1bviH6u0OcOshUaxSbqTVn6gBWOaEGfcFpY6UvOPeWFK0saDjIFbLf9uS4gE4fLCq1hz fnJqrIImWIk7tm30= X-Received: by 2002:a17:906:7156:: with SMTP id z22mr6274821ejj.441.1610653085078; Thu, 14 Jan 2021 11:38:05 -0800 (PST) X-Google-Smtp-Source: ABdhPJx/Ny2ivo/t92m5vGPjZxhxB7AkF7vHPEPCww7VcuMzD+wwe2JVca1z7kbU3WFHB5a/DESS5g== X-Received: by 2002:a17:906:7156:: with SMTP id z22mr6274814ejj.441.1610653084872; Thu, 14 Jan 2021 11:38:04 -0800 (PST) Received: from ?IPv6:2001:b07:6468:f312:c8dd:75d4:99ab:290a? ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id d6sm2305619ejy.114.2021.01.14.11.38.03 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 14 Jan 2021 11:38:04 -0800 (PST) Subject: Re: [PATCH] machine: add missing doc for memory-backend option To: Igor Mammedov , qemu-devel@nongnu.org References: <20210111222729.757402-1-imammedo@redhat.com> From: Paolo Bonzini Message-ID: Date: Thu, 14 Jan 2021 20:38:01 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <20210111222729.757402-1-imammedo@redhat.com> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=pbonzini@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -32 X-Spam_score: -3.3 X-Spam_bar: --- X-Spam_report: (-3.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.248, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.237, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mprivozn@redhat.com, ehabkost@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 11/01/21 23:27, Igor Mammedov wrote: > Add documentation for '-machine memory-backend' CLI option and > how to use it. > > PS: > While at it add a comment to x-use-canonical-path-for-ramblock-id, > to make sure it won't go away by accident. > > Signed-off-by: Igor Mammedov > --- > backends/hostmem.c | 8 ++++++++ > qemu-options.hx | 25 ++++++++++++++++++++++++- > 2 files changed, 32 insertions(+), 1 deletion(-) > > diff --git a/backends/hostmem.c b/backends/hostmem.c > index 4bde00e8e7..f6f4e818c7 100644 > --- a/backends/hostmem.c > +++ b/backends/hostmem.c > @@ -497,6 +497,14 @@ host_memory_backend_class_init(ObjectClass *oc, void *data) > host_memory_backend_get_share, host_memory_backend_set_share); > object_class_property_set_description(oc, "share", > "Mark the memory as private to QEMU or shared"); > + /* > + * Do not delete/rename option till 4.0 and older machine types exist, > + * Option will be used by upper layers to override (disable) canonical path > + * for ramblock-id set by compat properties on old machine types ( <= 4.0), > + * to keep migration working when backend is used for main RAM with > + * -machine memory-backend= option (main RAM historically used prefix-less > + * ramblock-id). > + */ > object_class_property_add_bool(oc, "x-use-canonical-path-for-ramblock-id", > host_memory_backend_get_use_canonical_path, > host_memory_backend_set_use_canonical_path); > diff --git a/qemu-options.hx b/qemu-options.hx > index 459c916d3d..c02628bd26 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -35,7 +35,8 @@ DEF("machine", HAS_ARG, QEMU_OPTION_machine, \ > " suppress-vmdesc=on|off disables self-describing migration (default=off)\n" > " nvdimm=on|off controls NVDIMM support (default=off)\n" > " memory-encryption=@var{} memory encryption object to use (default=none)\n" > - " hmat=on|off controls ACPI HMAT support (default=off)\n", > + " hmat=on|off controls ACPI HMAT support (default=off)\n" > + " memory-backend='backend-id' specifies explicitly provided backend for main RAM (default=none)\n", > QEMU_ARCH_ALL) > SRST > ``-machine [type=]name[,prop=value[,...]]`` > @@ -96,6 +97,28 @@ SRST > ``hmat=on|off`` > Enables or disables ACPI Heterogeneous Memory Attribute Table > (HMAT) support. The default is off. > + > + ``memory-backend='id'`` > + An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options. > + Allows to use a memory backend as main RAM. > + > + For example: > + :: > + -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on > + -machine memory-backend=pc.ram > + -m 512M > + > + Migration compatibility note: > + a) as backend id one shall use value of 'default-ram-id', advertised by > + machine type (available via ``query-machines`` QMP command) > + b) for machine types 4.0 and older, user shall > + use ``x-use-canonical-path-for-ramblock-id=on`` backend option, > + if migration to/from old QEMU (<5.0) is expected. > + For example: > + :: > + -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=on > + -machine memory-backend=pc.ram > + -m 512M > ERST > > HXCOMM Deprecated by -machine > Queued, thanks. Paolo