linux-kernel - Re: [PATCH v2] arch/x86: Fix boot_cpu

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Message-ID: <92d17176-e7cd-134c-c6aa-0507f8599cfe@redhat.com>
Date:   Wed, 1 Aug 2018 11:55:42 -0400
From:   Prarit Bhargava <prarit@...hat.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     linux-edac@...r.kernel.org, linux-kernel@...r.kernel.org,
        sironi@...zon.de, tony.luck@...el.com,
        Oleksandr Natalenko <oleksandr@...alenko.name>
Subject: Re: [PATCH v2] arch/x86: Fix boot_cpu_data.microcode version output



On 08/01/2018 11:43 AM, Borislav Petkov wrote:
> (dropping stable@)
> 
> On Tue, Jul 31, 2018 at 07:27:39AM -0400, Prarit Bhargava wrote:
>> I tested this on AMD Ryzen & Intel Broadwell system and dumped the
>> boot_cpu_data before and after a microcode update.  On the Intel
>> system I also did a fatal MCE using mce-inject to confirm the output
>> from the mce handling code.
> 
> Ok, sending the two patches I've massaged into submission as a reply to
> this message - please run them on your boxes. You can also inject MCEs
> on the AMD box to verify - simply enable CONFIG_X86_MCE_INJECT, go to
> debugfs and do, for example:
> 
> cd /sys/kernel/debug/mce-inject/
> echo 10 > /sys/devices/system/machinecheck/machinecheck0/check_interval
> echo 0x9c7d410092080813 > status; echo 0x000000006d3d483b > addr; echo 2 > cpu; echo 4 > bank; echo hw > flags
> echo 0xbc00200000010015 > status; echo 0x00000000942e4d98 > addr; echo 6 > cpu; echo 2 > bank; echo hw > flags
> echo 0xfe000010000b0c0f > status; echo 0xe1101add1e550012 > addr; echo 0xcafebeef > misc; echo 2 > cpu; echo hw > flags; echo 4 > bank
> 

Borislav, I'm not sure if you saw his comments but Oleksandr, cc'd, has an
objection to overwriting the stored microcode version in boot_cpu_data.  He has
found that information useful in debugging microcode issues.

P.

> Thanks!
>