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Date: Thu, 5 Jul 2018 13:47:20 +0300
From: Konstantin Belousov <kostikbel@gmail.com>
To: Pete French <petefrench@ingresso.co.uk>
Cc: avg@freebsd.org, eric@vangyzen.net, freebsd-stable@freebsd.org,
 freebsd@hda3.com, truckman@FreeBSD.org
Subject: Re: Ryzen issues on FreeBSD ? (with sort of workaround)
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On Thu, Jul 05, 2018 at 11:43:29AM +0100, Pete French wrote:
> > It does not make any sense to even try to access the chicken bits
> > MSRs when running under virtualization.  It is the duty of the
> > hypervisor to configure hardware. 
> 
> I would tend to agree with you :-) I was kind of surprised to read that they
> are actually saved and restored as part of a VM context switch in fact.
Why do you state that they are saved/restored ?  What is the evidence ?

> 
> > I updated the patch.
> 
> Thanks I shall try this now on my workstation and the Epyc virtual machine

On VM the patch should be NOP, testing it is a waste of time IMO.