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=-15.4 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,URIBL_BLOCKED, 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 1A21EC433E0 for ; Fri, 26 Feb 2021 16:25:28 +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 8EA5764EC0 for ; Fri, 26 Feb 2021 16:25:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8EA5764EC0 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]:59574 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lFfvi-0000V4-Ia for qemu-devel@archiver.kernel.org; Fri, 26 Feb 2021 11:25:26 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:50572) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lFfuM-0007Xk-Rk for qemu-devel@nongnu.org; Fri, 26 Feb 2021 11:24:02 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:51034) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lFfuK-0004le-6L for qemu-devel@nongnu.org; Fri, 26 Feb 2021 11:24:02 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1614356638; 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=08Dm4BdMhHlTjs7ePfZNXxj+SgRo/TrkhcclfF2dnu0=; b=HYvq69BbpL04tpncc+Pr2LUDiRPKrLpsRobyX65jDx+B+zRXZ3T+A8/+9aks5ktGdz8+Yf 71vWhSFWICcMgePMmokogsRToRqRvwQGvY1toxVw4ret9wEY2ma4ExDNTqRtTwnvf8enaW UMOfPd8g2KW06GnQ7N40Xg2E7cAfO48= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-347-2TaMN-OmOmeoD1BGv_gTug-1; Fri, 26 Feb 2021 11:23:56 -0500 X-MC-Unique: 2TaMN-OmOmeoD1BGv_gTug-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0A44080402C; Fri, 26 Feb 2021 16:23:55 +0000 (UTC) Received: from [10.3.113.12] (ovpn-113-12.phx2.redhat.com [10.3.113.12]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 007C51A8A3; Fri, 26 Feb 2021 16:23:47 +0000 (UTC) To: Kevin Wolf , qemu-devel@nongnu.org References: <20210224135255.253837-1-kwolf@redhat.com> <20210224135255.253837-8-kwolf@redhat.com> From: Eric Blake Organization: Red Hat, Inc. Subject: Re: [PATCH v2 07/31] qapi/qom: Add ObjectOptions for memory-backend-* Message-ID: Date: Fri, 26 Feb 2021 10:23:46 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <20210224135255.253837-8-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eblake@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 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, NICE_REPLY_A=-0.349, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: lvivier@redhat.com, thuth@redhat.com, pkrempa@redhat.com, berrange@redhat.com, ehabkost@redhat.com, qemu-block@nongnu.org, libvir-list@redhat.com, jasowang@redhat.com, armbru@redhat.com, mreitz@redhat.com, kraxel@redhat.com, pbonzini@redhat.com, dgilbert@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2/24/21 7:52 AM, Kevin Wolf wrote: > This adds a QAPI schema for the properties of the memory-backend-* > objects. > > HostMemPolicy has to be moved to an include file that can be used by the > storage daemon, too, because ObjectOptions must be the same in all > binaries if we don't want to compile the whole code multiple times. > > Signed-off-by: Kevin Wolf > --- > qapi/common.json | 20 ++++++++ > qapi/machine.json | 22 +-------- > qapi/qom.json | 118 +++++++++++++++++++++++++++++++++++++++++++++- > 3 files changed, 138 insertions(+), 22 deletions(-) > > +++ b/qapi/qom.json > +## > +# @MemoryBackendProperties: > +# > +# Properties for objects of classes derived from memory-backend. > +# > +# @merge: if true, mark the memory as mergeable (default depends on the machine > +# type) > +# > +# @dump: if true, include the memory in core dumps (default depends on the > +# machine type) Interesting choice to flip the description text from its previous wording, but fine by me: object_class_property_set_description(oc, "dump", "Set to 'off' to exclude from core dump"); > +# > +# @host-nodes: the list of NUMA host nodes to bind the memory to > +# > +# @policy: the NUMA policy (default: 'default') > +# > +# @prealloc: if true, preallocate memory (default: false) Not quite in the same order as backends/hostmem.c:host_memory_backend_class_init() (alphabetic here instead of matching the C code declaration order), but that doesn't impact QMP semantics, and I was able to match everything up in the end. > +# > +# @prealloc-threads: number of CPU threads to use for prealloc (default: 1) > +# > +# @share: if false, the memory is private to QEMU; if true, it is shared > +# (default: false) > +# > +# @size: size of the memory region in bytes > +# > +# @x-use-canonical-path-for-ramblock-id: if true, the canoncial path is used > +# for ramblock-id. Disable this for 4.0 > +# machine types or older to allow > +# migration with newer QEMU versions. > +# (default: false generally, but true > +# for machine types <= 4.0) The comment in the C code mentions that in spite of the x- prefix, we have to treat this as a stable interface until 4.0 machines disappear. Do we need any of that sentiment in the documentation here? > +# > +# Since: 2.1 > +## > +{ 'struct': 'MemoryBackendProperties', > + 'data': { '*dump': 'bool', > + '*host-nodes': ['uint16'], > + '*merge': 'bool', > + '*policy': 'HostMemPolicy', > + '*prealloc': 'bool', > + '*prealloc-threads': 'uint32', > + '*share': 'bool', > + 'size': 'size', > + '*x-use-canonical-path-for-ramblock-id': 'bool' } } > + > +## > +# @MemoryBackendFileProperties: > +# > +# Properties for memory-backend-file objects. > +# > +# @align: the base address alignment when QEMU mmap(2) @mem-path. Some > +# backend store specified by @mem-path requires an alignment different Grammar feels off. Would it read better as ...when QEMU mmap(2)s @mem-path. Some backend stores specified by @mem-path require an... > +# than the default one used by QEMU, e.g. the device DAX /dev/dax0.0 > +# requires 2M alignment rather than 4K. In such cases, users can > +# specify the required alignment via this option. > +# 0 selects a default alignment (currently the page size). (default: 0) Again, not in the same order as backends/hostmem-file.c:file_backend_class_init(), but it matches up. > +# > +# @discard-data: if true, the file contents can be destroyed when QEMU exits, > +# to avoid unnecessarily flushing data to the backing file. Note > +# that ``discard-data`` is only an optimization, and QEMU might > +# not discard file contents if it aborts unexpectedly or is > +# terminated using SIGKILL. (default: false) > +# > +# @mem-path: the path to either a shared memory or huge page filesystem mount > +# > +# @pmem: specifies whether the backing file specified by @mem-path is in > +# host persistent memory that can be accessed using the SNIA NVM > +# programming model (e.g. Intel NVDIMM). > +# > +# @readonly: if true, the backing file is opened read-only; if false, it is > +# opened read-write. (default: false) > +# > +# Since: 2.1 > +## > +{ 'struct': 'MemoryBackendFileProperties', > + 'base': 'MemoryBackendProperties', > + 'data': { '*align': 'size', > + '*discard-data': 'bool', > + 'mem-path': 'str', > + '*pmem': 'bool', To match the C code, this should be '*pmem': { 'type':'bool', 'if':'defined(CONFIG_LIBPMEM)' }, > + '*readonly': 'bool' } } > + > +## > +# @MemoryBackendMemfdProperties: > +# > +# Properties for memory-backend-memfd objects. > +# > +# The @share boolean option is true by default with memfd. > +# > +# @hugetlb: if true, the file to be created resides in the hugetlbfs filesystem > +# (default: false) > +# > +# @hugetlbsize: the hugetlb page size on systems that support multiple hugetlb > +# page sizes (it must be a power of 2 value supported by the > +# system). 0 selects a default page size. This option is ignored > +# if @hugetlb is false. (default: 0) > +# > +# @seal: if true, create a sealed-file, which will block further resizing of > +# the memory (default: true) > +# > +# Since: 2.12 > +## > +{ 'struct': 'MemoryBackendMemfdProperties', > + 'base': 'MemoryBackendProperties', > + 'data': { '*hugetlb': 'bool', > + '*hugetlbsize': 'size', > + '*seal': 'bool' } } backends/hostmem-memfd.c makes 'hugetlb' and 'hugetlbsize' conditional on qemu_memfd_check(MFD_HUGETLB), and only registers the overal type based on qemu_memfd_check(MFD_ALLOW_SEALING). In turn, qemu_memfd_check returns false except for CONFIG_LINUX,... > + > ## > # @ObjectType: > # > @@ -287,7 +395,10 @@ > 'cryptodev-backend-builtin', > 'cryptodev-vhost-user', > 'dbus-vmstate', > - 'iothread' > + 'iothread', > + 'memory-backend-file', > + 'memory-backend-memfd', > + 'memory-backend-ram' > ] } > > ## > @@ -314,7 +425,10 @@ > 'cryptodev-backend-builtin': 'CryptodevBackendProperties', > 'cryptodev-vhost-user': 'CryptodevVhostUserProperties', > 'dbus-vmstate': 'DBusVMStateProperties', > - 'iothread': 'IothreadProperties' > + 'iothread': 'IothreadProperties', > + 'memory-backend-file': 'MemoryBackendFileProperties', > + 'memory-backend-memfd': 'MemoryBackendMemfdProperties', ...so I'm wondering if this branch should be: 'memory-backend-memfd', { 'type':'MemoryBackendMemfdProperties', 'if': 'defined(CONFIG_LINUX)' }, and whether we are risking problems by always having the 'hugetlb*' fields even when the runtime does not register them. > + 'memory-backend-ram': 'MemoryBackendProperties' > } } > > ## > Because of my questions on conditional compilation, I'm not comfortable with R-b yet. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org