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=-3.5 required=3.0 tests=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 6FF62C10DCE for ; Wed, 18 Mar 2020 17:28:49 +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 35BAD20752 for ; Wed, 18 Mar 2020 17:28:49 +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="hPvza3jx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 35BAD20752 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]:56524 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jEcUq-0002AZ-Ds for qemu-devel@archiver.kernel.org; Wed, 18 Mar 2020 13:28:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37963) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jEcUB-0001kX-5k for qemu-devel@nongnu.org; Wed, 18 Mar 2020 13:28:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jEcU7-0002ch-9b for qemu-devel@nongnu.org; Wed, 18 Mar 2020 13:28:05 -0400 Received: from us-smtp-delivery-74.mimecast.com ([216.205.24.74]:39628) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jEcU7-0002bX-5p for qemu-devel@nongnu.org; Wed, 18 Mar 2020 13:28:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1584552482; 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=NCAqA9MwGPTVHWbpP3JTc3SIku0UB7/aYOVrwRvsiAw=; b=hPvza3jxXI8z7L/Cp3vkSLVQFJbq/16vTxBpF/+GVFvIFpzG7D0eE9kWN+euDEOm1gcpn8 iPYUslWIXkbLdMVa57dVnIciw1cw7TlX4SMtgVVctDKKnLWL4jl2SyvBloPPWeddyL2AdP ppWaMeZEEfCgvyyE37Fje6JwZhkiZp4= 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-481-jwkcAKdrOLObc_WP74oCNw-1; Wed, 18 Mar 2020 13:28:01 -0400 X-MC-Unique: jwkcAKdrOLObc_WP74oCNw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BFC49189D6D6; Wed, 18 Mar 2020 17:27:59 +0000 (UTC) Received: from gondolin (ovpn-113-129.ams2.redhat.com [10.36.113.129]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9CF95BBBC5; Wed, 18 Mar 2020 17:27:55 +0000 (UTC) Date: Wed, 18 Mar 2020 18:27:53 +0100 From: Cornelia Huck To: Janosch Frank Subject: Re: [PATCH v10 05/16] s390x: protvirt: Inhibit balloon when switching to protected mode Message-ID: <20200318182753.4c48d8cb.cohuck@redhat.com> In-Reply-To: <20200318143047.2335-6-frankja@linux.ibm.com> References: <20200318143047.2335-1-frankja@linux.ibm.com> <20200318143047.2335-6-frankja@linux.ibm.com> Organization: Red Hat GmbH MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 216.205.24.74 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: borntraeger@de.ibm.com, qemu-s390x@nongnu.org, qemu-devel@nongnu.org, david@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, 18 Mar 2020 10:30:36 -0400 Janosch Frank wrote: > Ballooning in protected VMs can only be done when the guest shares the > pages it gives to the host. If pages are not shared, the integrity > checks will fail once those pages have been altered and are given back > to the guest. > > As we currently do not yet have a solution for this we will continue > like this: > > 1. We block ballooning now in QEMU (with this patch). > > 2. Later we will provide a change to virtio that removes the blocker > and adds VIRTIO_F_IOMMU_PLATFORM automatically by QEMU when doing the > protvirt switch. This is OK, as the balloon driver in Linux (the only > supported guest) will refuse to work with the IOMMU_PLATFORM feature > bit set. > > 3. Later, we can fix the guest balloon driver to accept the IOMMU > feature bit and correctly exercise sharing and unsharing of balloon > pages. > > Signed-off-by: Janosch Frank > Reviewed-by: David Hildenbrand > Reviewed-by: Christian Borntraeger > Reviewed-by: Claudio Imbrenda > --- > hw/s390x/s390-virtio-ccw.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) Reviewed-by: Cornelia Huck