Received: by 2002:a05:6358:3188:b0:123:57c1:9b43 with SMTP id q8csp37033151rwd; Tue, 11 Jul 2023 08:36:53 -0700 (PDT) X-Google-Smtp-Source: APBJJlG7vKvUHwR003LCebr0hF0/iUYnSgfPSk2FLJ9BcbXyKrz09mEtNlUB+awpayxeN+FD3VJ5 X-Received: by 2002:a17:902:d2d1:b0:1b8:c972:606c with SMTP id n17-20020a170902d2d100b001b8c972606cmr19143893plc.57.1689089812768; Tue, 11 Jul 2023 08:36:52 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1689089812; cv=none; d=google.com; s=arc-20160816; b=bpzwIBMl5Rvwnio57LQbK79Piqwf5HdLwMXirAEM5W0gvTHUM+I4OZUb9OsGwfzcOe 3zNE/Y1UnON/Sss7RsCRcL99dpBZBNgnLTz4Z2uRpSdK7wefRb5qP6gdsbCmxZwT7wF4 guvlue7BOJfaYMeE1ibLZR0HbmCDAz/taNbP3d6m+6VH/uRWx4wxlVbfIhZdHLnwaOCs LRUOYRqP7E68TUpd+4o1v3igwvKfejxt/zOm9jD1gHJAiXqadBvpfnw7j4870XbpYBUH ffDrrGxGIARCCt15uYdi5aQBdcVZYDULxmFza1E4MzicswdUq3vA53h6KHBF9zXfEJ8P OpOA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:date:user-agent:message-id:subject:cc:to:from :references:in-reply-to:content-transfer-encoding:mime-version :dkim-signature; bh=ASYvEAEg58jzfr0uCG8q5lwqerxnbVzb/1DLtoelZms=; fh=taxXs5CCVrArxiyX4tSwxGor5TquVz2yJJQD3RnfiDM=; b=Lb5VSaW4XOhq0OqKZFN9kow4lxhqA6WTFfs7PfGtj/cT0cFd9QRco7dxla05fMCnCp 558lFOVGUIytICVks13ojWcD14WZt8bei0bi8BKeLUBd8VUK0dlUFm82OzRZwLVVaYfn 8VV43GrjoM2KHkeMa6ON/2qSjGDsqZaUqPSUaGh1oaxTbAYUwg9DHh38Prhn8Axgtk3v N8R0pgLnXdYIKHDL5752wj0uoG8JA/gNc/rUaGvu/VtHX0bg2ofSIrtu/K34SMmubiN4 jywubASw05awY4U3W6kyvWmxXKCSwGWF2vzpdHVPoKWXZvHd6GnzN0d4HUeMCGNWPDqd Xyzw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@ibm.com header.s=pp1 header.b=R7CsUwmu; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=NONE dis=NONE) header.from=ibm.com Return-Path: Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id a13-20020a170902eccd00b001b0473abd39si1784954plh.483.2023.07.11.08.36.39; Tue, 11 Jul 2023 08:36:52 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@ibm.com header.s=pp1 header.b=R7CsUwmu; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=NONE dis=NONE) header.from=ibm.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231810AbjGKPSt (ORCPT + 99 others); Tue, 11 Jul 2023 11:18:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38044 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231678AbjGKPSi (ORCPT ); Tue, 11 Jul 2023 11:18:38 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 75CFB9E; Tue, 11 Jul 2023 08:18:37 -0700 (PDT) Received: from pps.filterd (m0356517.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 36BFF2No016941; Tue, 11 Jul 2023 15:18:37 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=content-type : mime-version : content-transfer-encoding : in-reply-to : references : from : to : cc : subject : message-id : date; s=pp1; bh=ASYvEAEg58jzfr0uCG8q5lwqerxnbVzb/1DLtoelZms=; b=R7CsUwmucePLq2g0B2VCiRUtILvLSwruLlDFlyOf3RE38UuTq73Q9wpgJe6Hu03hZc7p jlhzWieSLRp3sowz3jZXuLWMV6M2YA+CF1NFZL00tvbxZQrUIpveBlfTO841IUZhFLnw AUImM/vvLoT0GNhXTFns19CDP/VrCjnJPJ5LdTCVSYlgpuEB4wGbuih9e0hAh9rfEydQ I8cArSjHk4mO4fBAPD+Xno+VxgA6T4OeWF2ElERyLPhfUCDq72PbMwkKcHJkfWWbVH80 Kr5wOQBPEx1lH2BNB3dGoMqpESr1AyY8RtuDmp2juq1bqtCh/bnkG6sqEr0ERTBc/WyP IQ== Received: from ppma06fra.de.ibm.com (48.49.7a9f.ip4.static.sl-reverse.com [159.122.73.72]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3rs9j803yg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 11 Jul 2023 15:18:36 +0000 Received: from pps.filterd (ppma06fra.de.ibm.com [127.0.0.1]) by ppma06fra.de.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 36B7fD5Y018540; Tue, 11 Jul 2023 15:18:34 GMT Received: from smtprelay02.fra02v.mail.ibm.com ([9.218.2.226]) by ppma06fra.de.ibm.com (PPS) with ESMTPS id 3rpy2e9d3t-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 11 Jul 2023 15:18:34 +0000 Received: from smtpav05.fra02v.mail.ibm.com (smtpav05.fra02v.mail.ibm.com [10.20.54.104]) by smtprelay02.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 36BFITYv5309020 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 11 Jul 2023 15:18:29 GMT Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EBA8620040; Tue, 11 Jul 2023 15:18:28 +0000 (GMT) Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C6D962004B; Tue, 11 Jul 2023 15:18:28 +0000 (GMT) Received: from t14-nrb (unknown [9.171.51.229]) by smtpav05.fra02v.mail.ibm.com (Postfix) with ESMTP; Tue, 11 Jul 2023 15:18:28 +0000 (GMT) Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable In-Reply-To: <20230705111937.33472-2-imbrenda@linux.ibm.com> References: <20230705111937.33472-1-imbrenda@linux.ibm.com> <20230705111937.33472-2-imbrenda@linux.ibm.com> From: Nico Boehr To: Claudio Imbrenda , kvm@vger.kernel.org Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, frankja@linux.ibm.com, mhartmay@linux.ibm.com, nsg@linux.ibm.com, borntraeger@de.ibm.com Subject: Re: [PATCH v2 1/2] KVM: s390: pv: simplify shutdown and fix race Message-ID: <168908870840.9488.10883720390869049418@t14-nrb> User-Agent: alot/0.8.1 Date: Tue, 11 Jul 2023 17:18:28 +0200 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 1GAatIAo8lgqXvCgI3AThbYOnw_A0UlB X-Proofpoint-GUID: 1GAatIAo8lgqXvCgI3AThbYOnw_A0UlB X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.957,Hydra:6.0.591,FMLib:17.11.176.26 definitions=2023-07-11_08,2023-07-11_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 spamscore=0 impostorscore=0 malwarescore=0 lowpriorityscore=0 clxscore=1011 adultscore=0 mlxscore=0 mlxlogscore=841 suspectscore=0 priorityscore=1501 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2305260000 definitions=main-2307110135 X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Quoting Claudio Imbrenda (2023-07-05 13:19:36) > Simplify the shutdown of non-protected VMs. There is no need to do > complex manipulations of the counter if it was zero. >=20 > This also fixes a very rare race which caused pages to be torn down > from the address space with a non-zero counter even on older machines > that don't support the UVC instruction, causing a crash. >=20 > Reported-by: Marc Hartmayer > Fixes: fb491d5500a7 ("KVM: s390: pv: asynchronous destroy for reboot") > Signed-off-by: Claudio Imbrenda Reviewed-by: Nico Boehr