From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [PATCH 3/4] x86, AMD: Fix crash as Xen Dom0 on AMD Trinity systems Date: Wed, 06 Jun 2012 15:00:14 -0700 Message-ID: <4FCFD2EE.8060508@zytor.com> References: <1338562358-28182-1-git-send-email-bp@amd64.org> <1338562358-28182-4-git-send-email-bp@amd64.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1338562358-28182-4-git-send-email-bp@amd64.org> Sender: linux-kernel-owner@vger.kernel.org To: Borislav Petkov Cc: Konrad Rzeszutek Wilk , Jacob Shin , Andre Przywara , jeremy@goop.org, xen-devel@lists.xensource.com, LKML , Jan Beulich , Ingo Molnar , Thomas Gleixner , Andreas Herrmann , stable@vger.kernel.org.#.3.4+, Borislav Petkov List-Id: xen-devel@lists.xenproject.org On 06/01/2012 07:52 AM, Borislav Petkov wrote: > From: Andre Przywara > > f7f286a910221 ("x86/amd: Re-enable CPU topology extensions in case BIOS > has disabled it") wrongfully added code which used the AMD-specific > {rd,wr}msr variants for no real reason. > > This caused boot panics on xen which wasn't initializing the > {rd,wr}msr_safe_regs pv_ops members properly. > > This, in turn, caused a heated discussion leading to us reviewing all > uses of the AMD-specific variants and removing them where unneeded > (almost everywhere except an obscure K8 BIOS fix, see 6b0f43ddfa358). > > Finally, this patch switches to the standard {rd,wr}msr*_safe* variants > which should've been used in the first place anyway and avoided unneeded > excitation with xen. > > Signed-off-by: Andre Przywara > Cc: Andreas Herrmann > Cc: stable@vger.kernel.org # 3.4+ > Link: > [Boris: correct and expand commit message] > Signed-off-by: Borislav Petkov Why -stable? I though we had agreed that we didn't have an active problem (unclean hack, yes, but not an active problem) in 3.4/3.5 as it currently sits? -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.