From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753376AbaCNJ5l (ORCPT ); Fri, 14 Mar 2014 05:57:41 -0400 Received: from mail-ee0-f41.google.com ([74.125.83.41]:36861 "EHLO mail-ee0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751277AbaCNJ5j (ORCPT ); Fri, 14 Mar 2014 05:57:39 -0400 Message-ID: <5322D28C.9080009@redhat.com> Date: Fri, 14 Mar 2014 10:57:32 +0100 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Gleb Natapov CC: Marcelo Tosatti , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] KVM: SVM: fix cr8 intercept window References: <1394561478-8815-1-git-send-email-rkrcmar@redhat.com> <20140312010513.GA8131@amt.cnet> <20140312104047.GA7488@potion.brq.redhat.com> <53209741.3060204@redhat.com> <20140313135206.GB30596@minantech.com> <20140313170846.GA23297@potion.brq.redhat.com> In-Reply-To: <20140313170846.GA23297@potion.brq.redhat.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 13/03/2014 18:08, Radim Krčmář ha scritto: > > I agree that old code is wrong and the patch looks correct, but I only > > see how the bug may cause pending IRR to not be delivered in time, > > not how interrupt can disrupt a higher priority task. Right. Also, on SMP guests the effect would likely be just a deadlock if a lower-priority ISR interrupted a higher priority task and accessed shared data (since you need anyway a spinlock in addition to raising the IRQL). A more likely explanation is that if the remote processor delays an IPI too much, it will have a stable TLB entry. The resulting random corruption of paged memory is compatible with the BAD_POOL_HEADER error codes that Radim observed. > Paolo, can you change the last sentence to ", which means we don't > inject pending IRR immediately."? (or do we just forget it?) It's already in Linus's tree. Paolo