From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754453AbbIQJbZ (ORCPT ); Thu, 17 Sep 2015 05:31:25 -0400 Received: from mail.skyhub.de ([78.46.96.112]:50585 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754149AbbIQJbX (ORCPT ); Thu, 17 Sep 2015 05:31:23 -0400 Date: Thu, 17 Sep 2015 11:31:34 +0200 From: Borislav Petkov To: Ingo Molnar Cc: Andy Lutomirski , x86@kernel.org, Paolo Bonzini , Peter Zijlstra , KVM list , Arjan van de Ven , xen-devel , linux-kernel@vger.kernel.org, Linus Torvalds , Thomas Gleixner , Peter Zijlstra , Andrew Morton , "H. Peter Anvin" Subject: Re: [PATCH 0/3] x86/paravirt: Fix baremetal paravirt MSR ops Message-ID: <20150917093134.GC12316@nazgul.tnic> References: <20150917071920.GA14296@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20150917071920.GA14296@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 17, 2015 at 09:19:20AM +0200, Ingo Molnar wrote: > Most big distro kernels on bare metal have CONFIG_PARAVIRT=y (I checked Ubuntu and > Fedora), so we are potentially exposing a lot of users to problems. + SUSE. > Crashing the bootup on an unknown MSR is bad. Many MSR reads and writes are > non-critical and returning the 'safe' result is much better than crashing or > hanging the bootup. ... and prepending all MSR accesses with feature/CPUID checks is probably almost impossible. -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. --