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From: Jan Beulich <jbeulich@suse.com>
To: George Dunlap <george.dunlap@citrix.com>
Cc: AndrewCooper <andrew.cooper3@citrix.com>,
	Steven Haigh <netwiz@crc.id.au>, Andreas Kinzler <hfp@posteo.de>,
	xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: [Xen-devel] Ryzen 3xxx works with Windows
Date: Mon, 18 Nov 2019 13:54:40 +0100	[thread overview]
Message-ID: <b9bb16ee-88c3-ed78-e338-81dd08020fcf@suse.com> (raw)
In-Reply-To: <45f6c5bf-2d24-d3d7-1c61-f8e2da04b5b7@citrix.com>

On 18.11.2019 12:39, George Dunlap wrote:
> On 11/15/19 5:06 PM, Andreas Kinzler wrote:
>> Hello All,
>>
>> I compared the CPUID listings from Ryzen 2700X (attached as tar.xz) to
>> 3700X and found only very few differences. I added
>>
>> cpuid = [ "0x80000008:ecx=xxxxxxxxxxxxxxxx0100xxxxxxxxxxxx" ]
>>
>> to xl.cfg and then Windows runs great with 16 vCPUs. Cinebench R15 score
>> is >2050 which is more or less the bare metal value.
> 
> So this is setting those bits to 0100, or 4.

One of the many possible problems with our incrementing of this field
could be that this results in a value that in "reserved" as per AMD's
documentation. At least for some of the Fam17 models they document
exactly which values are "legal".

This may then (further) get in the way of OSes trying to fully split
APIC IDs into the parts correlating with the topological sub-units
(thread, core, core complex, die, socket).

Jan

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  parent reply	other threads:[~2019-11-18 12:55 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-15 17:06 [Xen-devel] Ryzen 3xxx works with Windows Andreas Kinzler
2019-11-15 17:13 ` George Dunlap
2019-11-18 10:34   ` Jan Beulich
2019-11-18 16:11   ` Andreas Kinzler
2019-11-18 16:25     ` George Dunlap
2019-11-19 23:11       ` Andreas Kinzler
2019-11-15 17:22 ` Steven Haigh
2019-11-18 11:39 ` [Xen-devel] [SUSPECTED SPAM]Ryzen " George Dunlap
2019-11-18 12:29   ` Jan Beulich
2019-11-18 12:36     ` [Xen-devel] Ryzen " Jan Beulich
2019-11-18 12:54   ` Jan Beulich [this message]
2019-11-18 15:15     ` George Dunlap
2019-11-18 15:26       ` Jan Beulich

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