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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 8BB27C2BA2B for ; Fri, 10 Apr 2020 09:32:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5B3E020769 for ; Fri, 10 Apr 2020 09:32:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="CZPq7nfV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726179AbgDJJcy (ORCPT ); Fri, 10 Apr 2020 05:32:54 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:55618 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725861AbgDJJcy (ORCPT ); Fri, 10 Apr 2020 05:32:54 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 03A9JBhs020013; Fri, 10 Apr 2020 09:32:39 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2020-01-29; bh=Ums9rtORUoERTp+Sz6iCrEwniL6ascuI/F+Lp1A7/ic=; b=CZPq7nfVZcUVlHkIyoJG8scMCIvrBwYLJGNHvjq7v7oPL6CeT692fSrNnI3a4cf/2e2/ nkiSWISFGfNfUKL1jJCEDin+hLjlnDcSskNlcamFKBCl3E3EJGlVIKWIEhv/4qsgwDtL j0SkHd0SRWkTW2Xr8PzQay6ZKoNzIOe/DhrEgcQSSlN4Ri9e0Ywr7iez/9bs1ZJ9yuWV jKMAq3d4a8bRDkcHjJYenh75w9qAjdW6WNPuABHlRvA4vmkyyopbQ6HjFngr6TmWNIT5 F3HZC1+Rwh+W6OyNrHVRY97Gk7P+WeUmZenQutNR7hRUy4/u/W/+hZoa5pDcDvJCtHDn IA== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2120.oracle.com with ESMTP id 309gw4hmbq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 10 Apr 2020 09:32:39 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 03A9HUTx162777; Fri, 10 Apr 2020 09:32:39 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userp3030.oracle.com with ESMTP id 3091m6wc8m-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 10 Apr 2020 09:32:39 +0000 Received: from abhmp0020.oracle.com (abhmp0020.oracle.com [141.146.116.26]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 03A9WbL9024236; Fri, 10 Apr 2020 09:32:37 GMT Received: from [10.159.147.187] (/10.159.147.187) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 10 Apr 2020 02:32:37 -0700 Subject: Re: [RFC PATCH 00/26] Runtime paravirt patching To: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= , linux-kernel@vger.kernel.org, x86@kernel.org Cc: peterz@infradead.org, hpa@zytor.com, jpoimboe@redhat.com, namit@vmware.com, mhiramat@kernel.org, bp@alien8.de, vkuznets@redhat.com, pbonzini@redhat.com, boris.ostrovsky@oracle.com, mihai.carabas@oracle.com, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, virtualization@lists.linux-foundation.org References: <20200408050323.4237-1-ankur.a.arora@oracle.com> From: Ankur Arora Message-ID: <37d755a7-8fc9-8cc8-5627-027a8479b6c7@oracle.com> Date: Fri, 10 Apr 2020 02:32:35 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9586 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 malwarescore=0 mlxlogscore=999 phishscore=0 spamscore=0 adultscore=0 suspectscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004100078 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9586 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 bulkscore=0 phishscore=0 lowpriorityscore=0 impostorscore=0 clxscore=1015 suspectscore=0 malwarescore=0 spamscore=0 mlxlogscore=999 mlxscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004100078 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-04-08 5:28 a.m., Jürgen Groß wrote: > On 08.04.20 07:02, Ankur Arora wrote: [ snip ] > > Quite a lot of code churn and hacks for a problem which should not > occur on a well administrated machine. Yeah, I agree the patch set is pretty large and clearly the NMI or the stop_machine() are completely out. That said, as I wrote in my other mail I think the problem is still worth solving. > Especially the NMI dependencies make me not wanting to Ack this series. The NMI solution did turn out to be pretty ugly. I was using it to solve two problems: avoid a deadlock where an NMI handler could use a lock while the stop_machine() thread is trying to rewrite the corresponding call-sites. And, needed to ensure that we don't lock and unlock using mismatched primitives. Thanks Ankur > > > Juergen