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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 8CBD9C43331 for ; Fri, 3 Apr 2020 12:16:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 61EDF20737 for ; Fri, 3 Apr 2020 12:16:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403916AbgDCMQq (ORCPT ); Fri, 3 Apr 2020 08:16:46 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:40148 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403836AbgDCMQq (ORCPT ); Fri, 3 Apr 2020 08:16:46 -0400 Received: from p5de0bf0b.dip0.t-ipconnect.de ([93.224.191.11] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jKLF5-0005yc-FS; Fri, 03 Apr 2020 14:16:11 +0200 Received: by nanos.tec.linutronix.de (Postfix, from userid 1000) id C5CE3103A01; Fri, 3 Apr 2020 14:16:10 +0200 (CEST) From: Thomas Gleixner To: Jim Mattson , "Kenneth R. Crudup" Cc: Steven Rostedt , Nadav Amit , Sean Christopherson , x86 , Paolo Bonzini , Fenghua Yu , Xiaoyao Li , Thomas Hellstrom , Tony Luck , Peter Zijlstra , Jessica Yu , Vitaly Kuznetsov , Wanpeng Li , kvm , LKML , Doug Covelli Subject: Re: [PATCH 3/3] KVM: VMX: Extend VMX's #AC interceptor to handle split lock #AC in guest In-Reply-To: References: <20200402124205.334622628@linutronix.de> <20200402155554.27705-1-sean.j.christopherson@intel.com> <20200402155554.27705-4-sean.j.christopherson@intel.com> <87sghln6tr.fsf@nanos.tec.linutronix.de> <20200402174023.GI13879@linux.intel.com> <87h7y1mz2s.fsf@nanos.tec.linutronix.de> <20200402205109.GM13879@linux.intel.com> <87zhbtle15.fsf@nanos.tec.linutronix.de> <08D90BEB-89F6-4D94-8C2E-A21E43646938@vmware.com> <20200402190839.00315012@gandalf.local.home> Date: Fri, 03 Apr 2020 14:16:10 +0200 Message-ID: <87tv20lq7p.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jim, Jim Mattson writes: > On Thu, Apr 2, 2020 at 4:16 PM Kenneth R. Crudup wrote: >> On Thu, 2 Apr 2020, Steven Rostedt wrote: >> >> > If we go the approach of not letting VM modules load if it doesn't have the >> > sld_safe flag set, how is this different than a VM module not loading due >> > to kabi breakage? >> >> Why not a compromise: if such a module is attempted to be loaded, print up >> a message saying something akin to "turn the parameter 'split_lock_detect' >> off" as we reject loading it- and if we see that we've booted with it off >> just splat a WARN_ON() if someone tries to load such modules? > > What modules are we talking about? I thought we were discussing L1 > hypervisors, which are just binary blobs. The only modules at the L0 > level are kvm and kvm_intel. Maybe in your world, but VmWare (which got this started), VirtualBox, Jailhouse and who knows what else _are_ L0 hypervisors. Otherwise we wouldn't have that conversation at all. Thanks, tglx