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

[Aravind Gopalakrishnan <aravind.gopalakrishnan@xxxxxxx>]

On 5/22/2014 10:56 AM, Andrew Cooper wrote:
> 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@xxxxxxx>
> > > 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
Ah. Okay, Will try again.

Thanks,
-Aravind.

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