linux-kernel - Re: [PATCH] x86, microcode, AMD: Fix patch level reporting for family15h

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Date:	Thu, 26 Sep 2013 18:18:31 -0500
From:	Suravee Suthikulpanit <suravee.suthikulpanit@....com>
To:	Andreas Herrmann <herrmann.der.user@...glemail.com>
CC:	<jacob.w.shin@...il.com>, <linux-kernel@...r.kernel.org>,
	Borislav Petkov <bp@...en8.de>
Subject: Re: [PATCH] x86, microcode, AMD: Fix patch level reporting for family15h

On 9/26/2013 6:06 PM, Andreas Herrmann wrote:
> On Fri, Sep 27, 2013 at 12:13:22AM +0200, Borislav Petkov wrote:
>> On Thu, Sep 26, 2013 at 04:54:32PM -0500, suravee.suthikulpanit@....com wrote:
>>> From: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
>>>
>>> On AMD family15h, applying microcode patch on the a core (core0)
>>> would also affect the other core (core1) in the same compute unit.
>>> The driver would skip applying the patch on core1, but it still
>>> need to update kernel structures to reflect the proper patch level.
>>>
>>> The current logic is not updating the struct ucode_cpu_info.cpu_sig.rev
>>> of the skipped core. This causes the /sys/devices/system/cpu/cpu1/microcode/version
>>> to report incorrect patch level as shown below:
>>>
>>> [   10.708841] microcode: CPU0: new patch_level=0x0600063d
>>> [   10.714256] microcode: CPU1: patch_level=0x06000626
>>> [   10.719345] microcode: CPU2: patch_level=0x06000626
>>> [   10.748095] microcode: CPU2: new patch_level=0x0600063d
>>> [   10.753365] microcode: CPU3: patch_level=0x06000626
>>> [   10.758264] microcode: CPU4: patch_level=0x06000626
>>> [   10.786999] microcode: CPU4: new patch_level=0x0600063d
>> Actually, this is collect_cpu_info_amd()'s normal operation and shows
>> that there's no need to apply a microcode patch on the odd core since
>> the even core's ucode has been updated.
> Hmm, I think Boris is right, above messages are just logging what
> happened during µcode update. I think the patch_level in "CPU1:
> patch_level=0x06000626" is based on c->microcode which is updated
> shortly after this message was printed.
>
> I assume with your patch, above message won't look different but just
> the contents in /sys/devices/system/cpu/cpu1/microcode/version will
> show the correct version, right?
>
>
> Andreas
>
Yes, the message in dmesg is still showing the same. Only the sysfs... 
version is now fixed.

Suravee

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