Re: [PATCH] x86, amd_ucode: Safeguard against #GP

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 22/05/14 16:53, Aravind Gopalakrishnan wrote:
> On 5/21/2014 5:08 PM, Andrew Cooper wrote:
>> On 21/05/2014 22:28, Aravind Gopalakrishnan wrote:
>>> When HW tries to load a corrupted patch, it generates #GP
>>> and hangs the system. Use wrmsr_safe instead so that we
>>> fail to load microcode gracefully.
>>>
>>> Example on a Fam15h system-
>>> (XEN) microcode: CPU0 collect_cpu_info: patch_id=0x6000626
>>> (XEN) microcode: CPU0 size 7870, block size 2586 offset 76 equivID
>>> 0x6012 rev 0x6000637
>>> (XEN) microcode: CPU0 found a matching microcode update with version
>>> 0x6000637 (current=0x6000626)
>>> (XEN) traps.c:3073: GPF (0000): ffff82d08016f682 -> ffff82d08022d9f8
>>> (XEN) microcode: CPU0 update from revision 0x6000637 to 0x6000626
>>> failed
>>>
>>> Signed-off-by: Aravind Gopalakrishnan <aravind.gopalakrishnan@amd.com>
>> I suspect that you will find with a *very* up-to-date master tree, an
>> early #GP should result in panic() instead of a hang, following
>> 279840d5ea646  (If it doesn't I would be interested to know)
>
> The console log states 'Panic on CPU0'. But system is basically hung
> after that.
> (attached snapshot)

I refer you to the last line :)

You have "noreboot" on your command line

~Andrew