From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [PATCH V2] x86, amd_ucode: Skip microcode updates for final levels Date: Mon, 3 Aug 2015 17:43:27 +0100 Message-ID: <55BF9A2F.3060709@citrix.com> References: <1438619749-1625-1-git-send-email-aravind.gopalakrishnan@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1438619749-1625-1-git-send-email-aravind.gopalakrishnan@amd.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Aravind Gopalakrishnan , jbeulich@suse.com Cc: boris.ostrovsky@oracle.com, keir@xen.org, Suravee.Suthikulpanit@amd.com, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 03/08/15 17:35, Aravind Gopalakrishnan wrote: > Some of older[Fam10h] systems require that certain number of > applied microcode patch levels should not be overwritten by > the microcode loader. Otherwise, system hangs are known to occur. > > The 'final_levels' of patch ids have been obtained empirically. > Refer bug https://bugzilla.suse.com/show_bug.cgi?id=913996 > for details of the issue. > > The short version is that people have predominantly noticed > system hang issues when trying to update microcode levels > beyond the patch IDs below. > [0x01000098, 0x0100009f, 0x010000af] > > From internal discussions, we gathered that OS/hypervisor > cannot reliably perform microcode updates beyond these levels > due to hardware issues. Therefore, we need to abort microcode > update process if we hit any of these levels. > > In this patch, we check for those microcode versions and abort > if the current core has one of those final patch levels applied > by the BIOS > > A linux version of the patch has already made it into tip- > http://marc.info/?l=linux-kernel&m=143703405627170 > > Signed-off-by: Aravind Gopalakrishnan Reviewed-by: Andrew Cooper