From: Oleksandr Natalenko <oleksandr@natalenko.name>
To: Prarit Bhargava <prarit@redhat.com>
Cc: bp@alien8.de, linux-edac@vger.kernel.org,
linux-kernel@vger.kernel.org, sironi@amazon.de,
stable@vger.kernel.org, tony.luck@intel.com
Subject: Re: [PATCH v2] arch/x86: Fix boot_cpu_data.microcode version output
Date: Wed, 01 Aug 2018 16:16:42 +0200 [thread overview]
Message-ID: <0a4c663887ecc1672d9927ed7256485b@natalenko.name> (raw)
In-Reply-To: <b84518d4-fc78-ca2a-7bde-ad6b5f6a7d83@redhat.com>
Hi.
On 01.08.2018 13:38, Prarit Bhargava wrote:
>> After this patch, do we preserve an original microcode version
>> somewhere? If no,
>> why? Sometimes it is useful while debugging another crash because of
>> faulty
>> microcode.
>>
> Interesting, and thanks for bringing this up. Oleksandr, under what
> circumstances would you want to know what the old version was. AFAICS
> it is no
> longer running and should not have an impact on the system?
Once the kernel log does not contain a printout regarding updated
microcode anymore (because the log buffer is limited in size and can be
overwritten) and once you have a vmcore, it is handy to use
boot_cpu_data to compare the microcode version with the per-CPU value to
find out that is was updated at all. Or, maybe, that can be inspected in
another way now?
--
Oleksandr Natalenko (post-factum)
next prev parent reply other threads:[~2018-08-01 14:16 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <<20180731112739.32338-1-prarit@redhat.com>
2018-08-01 6:38 ` Oleksandr Natalenko
2018-08-01 11:38 ` Prarit Bhargava
2018-08-01 14:16 ` Oleksandr Natalenko [this message]
2018-08-01 15:29 ` Borislav Petkov
2018-08-01 15:59 ` Luck, Tony
2018-08-01 16:01 ` Oleksandr Natalenko
2018-08-01 16:14 ` Boris Petkov
2018-06-01 12:19 [PATCH] x86/MCE: Get microcode revision from cpu_info instead of boot_cpu_data Borislav Petkov
2018-07-31 11:27 ` [PATCH v2] arch/x86: Fix boot_cpu_data.microcode version output Prarit Bhargava
2018-07-31 11:46 ` Sironi, Filippo
2018-07-31 13:00 ` Borislav Petkov
2018-07-31 15:31 ` Sironi, Filippo
2018-08-01 15:43 ` Borislav Petkov
2018-08-01 15:55 ` Prarit Bhargava
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