freebsd stable - Jul 2018 - Ryzen issues on FreeBSD ? (with sort of workaround)

On 03/07/2018 11:09, Konstantin Belousov wrote:
> On Tue, Jul 03, 2018 at 10:27:06AM +0100, Pete French wrote:
>>
>>> It is very likely that the latest microcode sets the chicken bits
for the
>>> known erratas already.  AFAIK, this is the best that a ucode update
>>> can typically do anyway.
>>>
>>
>> I just did some testing - it does do these bits:
> By 'it' you mean the microcode update/BIOS on your board ?
Yes, sorry. As I was testing without the patch I looked to see what the 
values were that it had set.

I may have got my hex wrong on the last two though I have to say - it 
may be setting all four bits.

-pete.

So, I got my first lockup in weeks, testing with the latest stable
and the patch which sets the kernel bits. But I cant say it its
Ryzen related or not.

Meanwhile I also got access to an Epyc server in Azure. Am also
runing the latest STABLE on that tp see how it goes. Interesting
thing there is that there appears to be no access to the MSR's.
They all appear as zerousing cpucontrol. I am not entirely surprised
by this as the are very low level, but I di think they were saved
and restored during context switches between virtual machines so I
was hoping to be able to set them. Is this normal ?

-pete.