DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 919003939C29
Subject: Re: CPU microcode reported wrong in /proc/cpuinfo
To: cygwin@cygwin.com
References: <DM6PR09MB404382AB07B3636AFAF09B97A5830@DM6PR09MB4043.namprd09.prod.outlook.com>
From: Brian Inglis <Brian.Inglis@SystematicSw.ab.ca>
Autocrypt: addr=Brian.Inglis@SystematicSw.ab.ca; prefer-encrypt=mutual;
 keydata=
 mDMEXopx8xYJKwYBBAHaRw8BAQdAnCK0qv/xwUCCZQoA9BHRYpstERrspfT0NkUWQVuoePa0
 LkJyaWFuIEluZ2xpcyA8QnJpYW4uSW5nbGlzQFN5c3RlbWF0aWNTdy5hYi5jYT6IlgQTFggA
 PhYhBMM5/lbU970GBS2bZB62lxu92I8YBQJeinHzAhsDBQkJZgGABQsJCAcCBhUKCQgLAgQW
 AgMBAh4BAheAAAoJEB62lxu92I8Y0ioBAI8xrggNxziAVmr+Xm6nnyjoujMqWcq3oEhlYGAO
 WacZAQDFtdDx2koSVSoOmfaOyRTbIWSf9/Cjai29060fsmdsDLg4BF6KcfMSCisGAQQBl1UB
 BQEBB0Awv8kHI2PaEgViDqzbnoe8B9KMHoBZLS92HdC7ZPh8HQMBCAeIfgQYFggAJhYhBMM5
 /lbU970GBS2bZB62lxu92I8YBQJeinHzAhsMBQkJZgGAAAoJEB62lxu92I8YZwUBAJw/74rF
 IyaSsGI7ewCdCy88Lce/kdwX7zGwid+f8NZ3AQC/ezTFFi5obXnyMxZJN464nPXiggtT9gN5
 RSyTY8X+AQ==
Organization: Systematic Software
Message-ID: <5f880838-55ad-6f6e-33a6-6a57d7ae9c92@SystematicSw.ab.ca>
Date: Wed, 10 Jun 2020 15:45:30 -0600
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101
 Thunderbird/68.9.0
MIME-Version: 1.0
In-Reply-To: <DM6PR09MB404382AB07B3636AFAF09B97A5830@DM6PR09MB4043.namprd09.prod.outlook.com>
Content-Language: en-CA
Precedence: list
Reply-To: cygwin@cygwin.com
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Errors-To: cygwin-bounces@cygwin.com
Sender: "Cygwin" <cygwin-bounces@cygwin.com>

On 2020-06-10 14:23, Lavrentiev, Anton (NIH/NLM/NCBI) [C] via Cygwin wrote:
>> I'll have to recheck how Linux handles these
> 
> JFYI I was in correspondence with the cpuid utility team lately, and they told me that Linux uses vendor-specific MSRs to pull that info out:
> 
>> Check out:
>>
>>    MSR_IA32_UCODE_REV
>>    MSR_AMD64_PATCH_LEVEL
>>
>> Both reference MSR 0x8b.

As does MS, as I also tracked down some older MS Windows microcode registry
values used, whose names also appear to be based on the earlier MSR names.
Using MSRs are not an option, as MS Windows appears to provide no documented
access to those register values, and they are only accessible from kernel level
drivers, which are not available for latest MS Windows (i.e. I don't trust
offered drivers that claim to provide MSR access!)

I have applied a patch for this, and rebuilt cygwin, but are having problems
testing with the new dll (as are some others), so need some time to figure out
what are the minimum synced pieces now required to be able to test!

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

This email may be disturbing to some readers as it contains
too much technical detail. Reader discretion is advised.
[Data in IEC units and prefixes, physical quantities in SI.]
--
Problem reports:      https://cygwin.com/problems.html
FAQ:                  https://cygwin.com/faq/
Documentation:        https://cygwin.com/docs.html
Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple