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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 E845DC4724C for ; Wed, 6 May 2020 16:13:32 +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 B4289208CA for ; Wed, 6 May 2020 16:13:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="fO2+sJR5" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B4289208CA 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]:40912 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jWMfr-0002QF-QY for qemu-devel@archiver.kernel.org; Wed, 06 May 2020 12:13:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:52866) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jWMf9-0001zY-4N for qemu-devel@nongnu.org; Wed, 06 May 2020 12:12:47 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:30782 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jWMf8-00016K-1G for qemu-devel@nongnu.org; Wed, 06 May 2020 12:12:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588781564; 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=HZRDjL7nazpxt3wSuOJ5/WwzUELoarexy41YvOu/dZk=; b=fO2+sJR5zdNpOEumdJoYB53TZHtU3uWK2wIhElMw2MpyGPkdmJaDT5H5qrK2BVyerrSL69 O7jeSlsdgDQcw6Qyh7v3xySBL4yMX96JOjg+tkh6H3dOu8Qd3G4qpbjnNvPBG+eNkcpw5B GSUxl7ZPtD9IWQKG8cXZXrg/GzyAr3o= 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-488-l-m5nLYwP7axoWQd8MLKoA-1; Wed, 06 May 2020 12:12:37 -0400 X-MC-Unique: l-m5nLYwP7axoWQd8MLKoA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E01D41005510; Wed, 6 May 2020 16:12:35 +0000 (UTC) Received: from [10.3.114.73] (ovpn-114-73.phx2.redhat.com [10.3.114.73]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5F6CA6299C; Wed, 6 May 2020 16:12:29 +0000 (UTC) Subject: Re: [PATCH v1 10/17] virtio-mem: Paravirtualized memory hot(un)plug To: David Hildenbrand , qemu-devel@nongnu.org References: <20200506094948.76388-1-david@redhat.com> <20200506094948.76388-11-david@redhat.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <051610a8-4773-2de5-0d4c-48e39791f05e@redhat.com> Date: Wed, 6 May 2020 11:12:23 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200506094948.76388-11-david@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Received-SPF: pass client-ip=205.139.110.61; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/06 05:50:09 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] 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_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN 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: Eduardo Habkost , kvm@vger.kernel.org, "Michael S . Tsirkin" , "Dr . David Alan Gilbert" , Markus Armbruster , qemu-s390x@nongnu.org, Igor Mammedov , Paolo Bonzini , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 5/6/20 4:49 AM, David Hildenbrand wrote: > This is the very basic/initial version of virtio-mem. An introduction to > virtio-mem can be found in the Linux kernel driver [1]. While it can be > used in the current state for hotplug of a smaller amount of memory, it > will heavily benefit from resizeable memory regions in the future. > > Each virtio-mem device manages a memory region (provided via a memory > backend). After requested by the hypervisor ("requested-size"), the > guest can try to plug/unplug blocks of memory within that region, in order > to reach the requested size. Initially, and after a reboot, all memory is > unplugged (except in special cases - reboot during postcopy). > > The guest may only try to plug/unplug blocks of memory within the usable > region size. The usable region size is a little bigger than the > requested size, to give the device driver some flexibility. The usable > region size will only grow, except on reboots or when all memory is > requested to get unplugged. The guest can never plug more memory than > requested. Unplugged memory will get zapped/discarded, similar to in a > balloon device. > > The block size is variable, however, it is always chosen in a way such that > THP splits are avoided (e.g., 2MB). The state of each block > (plugged/unplugged) is tracked in a bitmap. > > As virtio-mem devices (e.g., virtio-mem-pci) will be memory devices, we now > expose "VirtioMEMDeviceInfo" via "query-memory-devices". > > +++ b/qapi/misc.json > @@ -1354,19 +1354,56 @@ > } > } > > +## > +# @VirtioMEMDeviceInfo: > +# > +# @memdev: memory backend linked with the region > +# > +# Since: 5.1 Here you claim 5.1, > +## > +{ 'struct': 'VirtioMEMDeviceInfo', > + 'data': { '*id': 'str', > + 'memaddr': 'size', > + 'requested-size': 'size', > + 'size': 'size', > + 'max-size': 'size', > + 'block-size': 'size', > + 'node': 'int', > + 'memdev': 'str' > + } > +} > + > ## > # @MemoryDeviceInfo: > # > # Union containing information about a memory device > # > # nvdimm is included since 2.12. virtio-pmem is included since 4.1. > +# virtio-mem is included since 5.2. but here 5.2. They should probably be the same :) -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org