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=-6.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 2A302C10DCE for ; Wed, 18 Mar 2020 11:43:12 +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 E0C862076F for ; Wed, 18 Mar 2020 11:43:11 +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="OxTBl86+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E0C862076F 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]:49204 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jEX6N-00045J-3K for qemu-devel@archiver.kernel.org; Wed, 18 Mar 2020 07:43:11 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51432) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jEX5d-0003Rm-UJ for qemu-devel@nongnu.org; Wed, 18 Mar 2020 07:42:27 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jEX5c-0004my-I3 for qemu-devel@nongnu.org; Wed, 18 Mar 2020 07:42:25 -0400 Received: from us-smtp-delivery-74.mimecast.com ([63.128.21.74]:47189) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jEX5c-0004bB-88 for qemu-devel@nongnu.org; Wed, 18 Mar 2020 07:42:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1584531743; 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=NoF2tXLL+2rmnbX9do3XUmMoNsslmXyv5OuhY+nKjBo=; b=OxTBl86+V7MMxAfbJ6trIwacein+jNqkpynYYV2C4V5yF8Vu7VGnCqRhjgS87Nfb1VlhSL NI4DFnbpd+qeNzEpyeThAeE/4OwPznvuR/8TlnS7QEm5qLCnCZuumCl2amBP1vmS+HXbmo 8tOgx9GDYyKle6T2fdwNRSQQvOmX7+E= 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-342-8x4xAT3OPIq6INNMAgqwVw-1; Wed, 18 Mar 2020 07:42:21 -0400 X-MC-Unique: 8x4xAT3OPIq6INNMAgqwVw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8952A107ACC7; Wed, 18 Mar 2020 11:42:20 +0000 (UTC) Received: from gondolin (ovpn-113-129.ams2.redhat.com [10.36.113.129]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9A7435D9C5; Wed, 18 Mar 2020 11:42:16 +0000 (UTC) Date: Wed, 18 Mar 2020 12:42:14 +0100 From: Cornelia Huck To: Janosch Frank Subject: Re: [PATCH v9 04/15] s390x: protvirt: Inhibit balloon when switching to protected mode Message-ID: <20200318124214.15778f76.cohuck@redhat.com> In-Reply-To: <20200311132151.172389-5-frankja@linux.ibm.com> References: <20200311132151.172389-1-frankja@linux.ibm.com> <20200311132151.172389-5-frankja@linux.ibm.com> Organization: Red Hat GmbH MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 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] X-Received-From: 63.128.21.74 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, 11 Mar 2020 09:21:40 -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) add trailing '.' > > 2. Later we will provide a change to virtio that removes the blocker s/Later/Later,/ > and adds VIRTIO_F_IOMMU_PLATFORM automatically by QEMU when doing the > protvirt switch. This is ok as the guest balloon driver will reject to > work with the IOMMU change "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 "Later, we can fix the Linux guest balloon driver..." > feature bit and correctly exercise sharing and unsharing of balloon > pages again, missing trailing '.' > > Signed-off-by: Janosch Frank > Reviewed-by: David Hildenbrand > Reviewed-by: Christian Borntraeger > --- > hw/s390x/s390-virtio-ccw.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c > index deb31e060052d279..066e01f303c35671 100644 > --- a/hw/s390x/s390-virtio-ccw.c > +++ b/hw/s390x/s390-virtio-ccw.c > @@ -41,6 +41,7 @@ > #include "hw/qdev-properties.h" > #include "hw/s390x/tod.h" > #include "sysemu/sysemu.h" > +#include "sysemu/balloon.h" > #include "hw/s390x/pv.h" > #include "migration/blocker.h" > > @@ -326,6 +327,7 @@ static void s390_machine_unprotect(S390CcwMachineState *ms) > ms->pv = false; > migrate_del_blocker(pv_mig_blocker); > error_free_or_abort(&pv_mig_blocker); > + qemu_balloon_inhibit(false); > } > > static int s390_machine_protect(S390CcwMachineState *ms) > @@ -333,10 +335,12 @@ static int s390_machine_protect(S390CcwMachineState *ms) > Error *local_err = NULL; > int rc; > Maybe add a comment? /* * Ballooning on protected VMs needs support in the guest for * sharing and unsharing balloon pages. Block ballooning for * now, until we have a solution to make at least Linux guests * either support it or fail gracefully. */ > + qemu_balloon_inhibit(true); > error_setg(&pv_mig_blocker, > "protected VMs are currently not migrateable."); > rc = migrate_add_blocker(pv_mig_blocker, &local_err); > if (local_err) { > + qemu_balloon_inhibit(false); > error_report_err(local_err); > error_free_or_abort(&pv_mig_blocker); > return rc; > @@ -345,6 +349,7 @@ static int s390_machine_protect(S390CcwMachineState *ms) > /* Create SE VM */ > rc = s390_pv_vm_enable(); > if (rc) { > + qemu_balloon_inhibit(false); > error_report_err(local_err); > migrate_del_blocker(pv_mig_blocker); > error_free_or_abort(&pv_mig_blocker);