From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [PATCH V3] x86, amd_ucode: Skip microcode updates for final levels Date: Mon, 3 Aug 2015 23:51:23 +0100 Message-ID: <55BFF06B.50903@citrix.com> References: <1438630443-1904-1-git-send-email-aravind.gopalakrishnan@amd.com> <55BFC6D9.90501@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <55BFC6D9.90501@oracle.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: Boris Ostrovsky , Aravind Gopalakrishnan , jbeulich@suse.com Cc: keir@xen.org, Suravee.Suthikulpanit@amd.com, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 03/08/2015 20:54, Boris Ostrovsky wrote: > On 08/03/2015 03:34 PM, 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 > > Reviewed-by: Boris Ostrovsky For the avoidance of any confusion, I am happy for my R-b to stand, given this addition to the patch. ~Andrew