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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7334BC71145 for ; Wed, 23 Aug 2023 19:30:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237943AbjHWTaT (ORCPT ); Wed, 23 Aug 2023 15:30:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47688 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238098AbjHWTaA (ORCPT ); Wed, 23 Aug 2023 15:30:00 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5E9E10C8; Wed, 23 Aug 2023 12:29:58 -0700 (PDT) Received: from pps.filterd (m0353728.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 37NJCZGq030998; Wed, 23 Aug 2023 19:29:58 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=pp1; bh=8V1esxwklFErSUFnPK6XOA6s5/KCSCyZQLNUOEjUwVQ=; b=DYQLCFsvQm7ip5ocKtXS1uWIqlbbB2h59SlXyf2Fj18SRGwf6SBl7OdI3PoKnArd5CPE uFxkg1Ka6Rmg23WDAm6dxV4xBUwIawPNnBn7pthvJxEQ5RKr1y/FT/lzUkDBEEzOOW8H xqO1L4SbIgURfEWG2RmjwsQgcOTAIYp45o0zOHj9/NIEV/fEd06VcJ6HodPNRJN1ctyM 8zJ8KIBqOsi65CHT9Kpeuj/jqmFPfp9mTR8nJHzbOpdY812yl6FGn3d2rU+j8iBwyHEW in455Bi661CNMAXhS7ZZTMfou6y8JtWlUF3pqTSZkWeXNfyexUYWaHGPg5UuOuU7ztVO ew== Received: from ppma21.wdc07v.mail.ibm.com (5b.69.3da9.ip4.static.sl-reverse.com [169.61.105.91]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3snr2kgg3x-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 23 Aug 2023 19:29:58 +0000 Received: from pps.filterd (ppma21.wdc07v.mail.ibm.com [127.0.0.1]) by ppma21.wdc07v.mail.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 37NIjrrr016403; Wed, 23 Aug 2023 19:29:57 GMT Received: from smtprelay02.fra02v.mail.ibm.com ([9.218.2.226]) by ppma21.wdc07v.mail.ibm.com (PPS) with ESMTPS id 3sn227rxvj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 23 Aug 2023 19:29:57 +0000 Received: from smtpav04.fra02v.mail.ibm.com (smtpav04.fra02v.mail.ibm.com [10.20.54.103]) by smtprelay02.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 37NJTsww25690648 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 23 Aug 2023 19:29:54 GMT Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E839D2004B; Wed, 23 Aug 2023 19:29:53 +0000 (GMT) Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5514020040; Wed, 23 Aug 2023 19:29:53 +0000 (GMT) Received: from osiris (unknown [9.171.42.232]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTPS; Wed, 23 Aug 2023 19:29:53 +0000 (GMT) Date: Wed, 23 Aug 2023 21:29:51 +0200 From: Heiko Carstens To: Alexander Gordeev Cc: Michael Mueller , kvm@vger.kernel.org, linux-s390@vger.kernel.org, Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Vasily Gorbik , Viktor Mihajlovski Subject: Re: [PATCH] KVM: s390: fix gisa destroy operation might lead to cpu stalls Message-ID: <20230823192951.28372-A-hca@linux.ibm.com> References: <20230823124140.3839373-1-mimu@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-TM-AS-GCONF: 00 X-Proofpoint-GUID: mJu6Q59Hxe4ba6l_geAJbSrW0jFH3oY2 X-Proofpoint-ORIG-GUID: mJu6Q59Hxe4ba6l_geAJbSrW0jFH3oY2 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.957,Hydra:6.0.601,FMLib:17.11.176.26 definitions=2023-08-23_13,2023-08-22_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 mlxlogscore=270 mlxscore=0 phishscore=0 clxscore=1015 malwarescore=0 spamscore=0 bulkscore=0 suspectscore=0 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2308100000 definitions=main-2308230173 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, Aug 23, 2023 at 06:01:59PM +0200, Alexander Gordeev wrote: > On Wed, Aug 23, 2023 at 04:09:26PM +0200, Michael Mueller wrote: > > Does that make sense for you? > > Not really. If process_gib_alert_list() does guarantee the removal, > then it should be a condition, not the loop. > > But I am actually not into this code. Just wanted to point out that > cpu_relax() is removed from this loop and the two other loops within > process_gib_alert_list() do not have it either. Not sure if you are mainly referring to the missing cpu_relax(), however: any chance you missed that cpu_relax() translates only to barrier() on s390? So it really doesn't "relax" anything. cpu_relax() used to be a diagnose 0x44 (aka voluntary yield), but that caused many problems, therefore we removed that logic, and the only thing remaining is a no-op with compiler barrier semantics.