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=-6.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 B9A85C433E5 for ; Mon, 27 Jul 2020 10:04:07 +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 8359220672 for ; Mon, 27 Jul 2020 10:04:07 +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="AERsZrDb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8359220672 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]:56064 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jzzzK-00018G-Rh for qemu-devel@archiver.kernel.org; Mon, 27 Jul 2020 06:04:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44342) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jzzyf-0000Vs-Rn for qemu-devel@nongnu.org; Mon, 27 Jul 2020 06:03:25 -0400 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:47475 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 1jzzyd-000052-8y for qemu-devel@nongnu.org; Mon, 27 Jul 2020 06:03:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595844202; 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=ivy2XEBy58oI03WkVcrKvZFFGTzPEWgtS0K5KFwBdGg=; b=AERsZrDbbk++TsAOaIsJ5FDQhibkeqidDaf76fI7oL4pOqnonw4lLCBpRP/rNb0B6BoJdj 3j7zL+pCKHawezX94aEoxRLaakijCZOnPqch8UiJuCHhraO2h17In4n+uC2TAil5mpjsRJ kEwUID/bmIt3dB6br/fiTyVktPr2NI8= 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-270-W_qF33KRM0aA53-wLiWgrg-1; Mon, 27 Jul 2020 06:03:20 -0400 X-MC-Unique: W_qF33KRM0aA53-wLiWgrg-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 76E861009441; Mon, 27 Jul 2020 10:03:19 +0000 (UTC) Received: from gondolin (ovpn-112-210.ams2.redhat.com [10.36.112.210]) by smtp.corp.redhat.com (Postfix) with ESMTP id 71D7E19D82; Mon, 27 Jul 2020 10:03:11 +0000 (UTC) Date: Mon, 27 Jul 2020 12:03:08 +0200 From: Cornelia Huck To: David Hildenbrand Subject: Re: [PATCH RFCv3 9/9] s390x: initial support for virtio-mem Message-ID: <20200727120308.39a4c810.cohuck@redhat.com> In-Reply-To: <20200724143750.59836-10-david@redhat.com> References: <20200724143750.59836-1-david@redhat.com> <20200724143750.59836-10-david@redhat.com> Organization: Red Hat GmbH MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=205.139.110.61; envelope-from=cohuck@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/27 01:46:13 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, 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=-1, 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: Thomas Huth , Janosch Frank , "Michael S . Tsirkin" , Heiko Carstens , qemu-devel@nongnu.org, Halil Pasic , Christian Borntraeger , qemu-s390x@nongnu.org, Claudio Imbrenda , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, 24 Jul 2020 16:37:50 +0200 David Hildenbrand wrote: > Let's wire up the initial, basic virtio-mem implementation in QEMU. It will > have to see some important extensions (esp., resizeable allocations) > before it can be considered production ready. Also, the focus on the Linux > driver side is on memory hotplug, there are a lot of things optimize in > the future to improve memory unplug capabilities. However, the basics > are in place. > > Block migration for now, as we'll have to take proper care of storage > keys and storage attributes. Also, make sure to not hotplug huge pages > to a setup without huge pages. > > With a Linux guest that supports virtio-mem (and has > CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE set for now), a basic example. > > 1. Start a VM with 2G initial memory and a virtio-mem device with a maximum > capacity of 18GB (and an initial size of 300M): > sudo qemu-system-s390x \ > --enable-kvm \ > -m 2G,maxmem=20G \ > -smp 4 \ > -nographic \ > -chardev socket,id=monitor,path=/var/tmp/monitor,server,nowait \ > -mon chardev=monitor,mode=readline \ > -net nic -net user \ > -hda s390x.cow2 \ > -object memory-backend-ram,id=mem0,size=18G \ > -device virtio-mem-ccw,id=vm0,memdev=mem0,requested-size=300M > > 2. Query the current size of virtio-mem device: > (qemu) info memory-devices > Memory device [virtio-mem]: "vm0" > memaddr: 0x80000000 > node: 0 > requested-size: 314572800 > size: 314572800 > max-size: 19327352832 > block-size: 1048576 > memdev: /objects/mem0 > > 3. Request to grow it to 8GB: > (qemu) qom-set vm0 requested-size 8G > (qemu) info memory-devices > Memory device [virtio-mem]: "vm0" > memaddr: 0x80000000 > node: 0 > requested-size: 8589934592 > size: 8589934592 > max-size: 19327352832 > block-size: 1048576 > memdev: /objects/mem0 > > 4. Request to shrink it to 800M (might take a while, might not fully > succeed, and might not be able to remove memory blocks in Linux): > (qemu) qom-set vm0 requested-size 800M > (qemu) info memory-devices > Memory device [virtio-mem]: "vm0" > memaddr: 0x80000000 > node: 0 > requested-size: 838860800 > size: 838860800 > max-size: 19327352832 > block-size: 1048576 > memdev: /objects/mem0 > > Note 1: Due to lack of resizeable allocations, we will go ahead and > reserve a 18GB vmalloc area + size the QEMU RAM slot + KVM mamory slot > 18GB. echo 1 > /proc/sys/vm/overcommit_memory might be required for > now. In the future, this area will instead grow on actual demand and shrink > when possible. > > Note 2: Although virtio-mem-pci is wired up as well, it does not seem to > work currently on s390x due to lack of MSI-X. IIRC, you can trick virtio-pci into using msi-x via nvectors. Might be interesting to try. > > Signed-off-by: David Hildenbrand > --- > hw/s390x/Kconfig | 1 + > hw/s390x/Makefile.objs | 1 + > hw/s390x/s390-virtio-ccw.c | 121 ++++++++++++++++++++++++++++++++++++- > hw/virtio/virtio-mem.c | 2 + > 4 files changed, 123 insertions(+), 2 deletions(-)