From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751284AbeAYTNZ (ORCPT ); Thu, 25 Jan 2018 14:13:25 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:35925 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750994AbeAYTNY (ORCPT ); Thu, 25 Jan 2018 14:13:24 -0500 Date: Thu, 25 Jan 2018 20:13:04 +0100 (CET) From: Thomas Gleixner To: Dexuan Cui cc: David Woodhouse , Dexuan-Linux Cui , Alexey Dobriyan , "pbonzini@redhat.com" , "rkrcmar@redhat.com" , "mingo@redhat.com" , "hpa@zytor.com" , "dave.hansen@linux.intel.com" , "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" , "x86@kernel.org" , "arjan@linux.intel.com" Subject: RE: tip/master falls off NOP cliff with KPTI under KVM In-Reply-To: Message-ID: References: <20180110220814.GA29262@avx2> <20180110223457.GA1762@avx2> <1515624823.22302.260.camel@amazon.co.uk> <1516866801.30244.3.camel@infradead.org> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: multipart/mixed; BOUNDARY="8323329-1332931525-1516907585=:2203" 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323329-1332931525-1516907585=:2203 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT On Thu, 25 Jan 2018, Dexuan Cui wrote: > > From: David Woodhouse [mailto:dwmw2@infradead.org] > > Sent: Wednesday, January 24, 2018 23:53 > > On Wed, 2018-01-24 at 16:53 -0800, Dexuan-Linux Cui wrote: > > > On Wed, Jan 10, 2018 at 2:53 PM, Woodhouse, David > > wrote: > > > > > > > > On Thu, 2018-01-11 at 01:34 +0300, Alexey Dobriyan wrote: > > > > > > > > > > > > > > > Bisection points to > > > > > > > > > >         f3433c1010c6af61c9897f0f0447f81b991feac1 is the first bad > > commit > > > > >         commit f3433c1010c6af61c9897f0f0447f81b991feac1 > > > > >         Author: David Woodhouse > > > > >         Date:   Tue Jan 9 14:43:11 2018 +0000 > > > > > > > > > >             x86/retpoline/entry: Convert entry assembler indirect jumps > > > > Thanks. We've fixed the underlying problem with the alternatives > > > > mechanism, *and* changed the retpoline code not to actually rely on > > > > said fix. > > > Hi David and all, > > > It looks the latest upstream tree did fix the issue. > > > Can you please specify the related commit(s) that fixed the issue? > > > I need to cherry-pick the fix. I suppose a quick reply from you would save > > >  me a lot of time. :-) > > > > Hi Dexuan, > > > > The above commit didn't ever make it into Linus' tree in that form; the > > issues were fixed beforehand. So there isn't a subsequent commit that > > fixes it. I think it might have just been removing some .align 16 from > > nospec-branch.h? > > > > The correct version has been backported to 4.9 and 4.4 releases > > already; if you pulled in an early version directly from tip/x86/pti > > then I'd recommend you drop it and pull in the real version instead. > > Thanks for the clarification, David! > I'm going to pull the latest version from Linus's master branch. The simpler solution is to pull from tip x86/pti which is still 4.14 based and contains only the stuff which has to do with these issues. It's mostly in Linus tree already except for the topmost 3 patches. Thanks, tglx --8323329-1332931525-1516907585=:2203--