From patchwork Tue Jun 14 12:13:54 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Cornelia Huck X-Patchwork-Id: 9175761 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 93CCB6075D for ; Tue, 14 Jun 2016 12:28:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8406E22473 for ; Tue, 14 Jun 2016 12:28:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 78AEE27E78; Tue, 14 Jun 2016 12:28:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 5A39822473 for ; Tue, 14 Jun 2016 12:28:26 +0000 (UTC) Received: from localhost ([::1]:34861 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bCnSD-00055B-Bg for patchwork-qemu-devel@patchwork.kernel.org; Tue, 14 Jun 2016 08:28:25 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34278) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bCnEU-0008Vh-Pm for qemu-devel@nongnu.org; Tue, 14 Jun 2016 08:14:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bCnEK-0002Sa-FI for qemu-devel@nongnu.org; Tue, 14 Jun 2016 08:14:13 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:59729 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bCnEK-0002SM-9E for qemu-devel@nongnu.org; Tue, 14 Jun 2016 08:14:04 -0400 Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u5ECDpMH019002 for ; Tue, 14 Jun 2016 08:14:04 -0400 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0b-001b2d01.pphosted.com with ESMTP id 23je2k7vmq-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 14 Jun 2016 08:14:03 -0400 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Tue, 14 Jun 2016 13:14:01 +0100 X-IBM-Helo: d06dlp01.portsmouth.uk.ibm.com X-IBM-MailFrom: cornelia.huck@de.ibm.com X-IBM-RcptTo: qemu-devel@nongnu.org Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by d06dlp01.portsmouth.uk.ibm.com (Postfix) with ESMTP id BC40917D806E for ; Tue, 14 Jun 2016 13:15:13 +0100 (BST) Received: from d06av07.portsmouth.uk.ibm.com (d06av07.portsmouth.uk.ibm.com [9.149.37.248]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u5ECE0lN7995690 for ; Tue, 14 Jun 2016 12:14:00 GMT Received: from d06av07.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av07.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u5ECDxYs005776 for ; Tue, 14 Jun 2016 08:14:00 -0400 Received: from gondolin.boeblingen.de.ibm.com (dyn-9-152-224-202.boeblingen.de.ibm.com [9.152.224.202]) by d06av07.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id u5ECDvp8005597 (version=TLSv1/SSLv3 cipher=AES256-SHA256 bits=256 verify=NO); Tue, 14 Jun 2016 08:13:59 -0400 From: Cornelia Huck To: peter.maydell@linaro.org Date: Tue, 14 Jun 2016 14:13:54 +0200 X-Mailer: git-send-email 2.9.0 In-Reply-To: <20160614121355.9320-1-cornelia.huck@de.ibm.com> References: <20160614121355.9320-1-cornelia.huck@de.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16061412-0020-0000-0000-000001C01B25 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16061412-0021-0000-0000-00001C5856E2 Message-Id: <20160614121355.9320-7-cornelia.huck@de.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2016-06-14_05:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1606140137 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] X-Received-From: 148.163.158.5 Subject: [Qemu-devel] [PULL 6/7] s390x: Limit s390-ccw machines to 248 CPUs X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Cornelia Huck , borntraeger@de.ibm.com, jfrei@linux.vnet.ibm.com, agraf@suse.de, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP From: Christian Borntraeger The sclp scp read info call fills in a buffer with information about the system. With more than 248 CPUs we overflow the 4k buffer of the SCCB, leading to random data corruption. Basically ALL guest operating systems call scp read info, so let's limit the machines to 248 CPUs to make it obvious that >=249 does not work. As KVM also limits itself to 248 and TCG on s390 does not support SMP, this should cause no regression for any user as no VMs with more than 248 VCPUs were ever possible. Signed-off-by: Christian Borntraeger Reviewed-by: David Hildenbrand Reviewed-by: Boris Fiuczynski Signed-off-by: Cornelia Huck --- hw/s390x/s390-virtio-ccw.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c index 95ff5e3..e257ca5 100644 --- a/hw/s390x/s390-virtio-ccw.c +++ b/hw/s390x/s390-virtio-ccw.c @@ -204,7 +204,7 @@ static void ccw_machine_class_init(ObjectClass *oc, void *data) mc->no_parallel = 1; mc->no_sdcard = 1; mc->use_sclp = 1; - mc->max_cpus = 255; + mc->max_cpus = 248; mc->get_hotplug_handler = s390_get_hotplug_handler; hc->plug = s390_machine_device_plug; nc->nmi_monitor_handler = s390_nmi;