Re: [Qemu-devel] Qemu the right way -[Subthread Cores]

[liebrecht@grossmann-venter.com]

For the record I have no crashes with
-cpu host It works perfectly. Although I can only see 2 cpus in windows 
with 4 showing up in devicemanager.

The first link you sent was actually the first thing I tried and I was 
already aware of that one.
It made no difference whatsoever.
My bios is latest on the rackserver , but it does not have the maximum 
core option in the bios.

Let me update the os to latest patches. I can vaguely remeber a similar 
problem running wi7 pro natively. I think out of the box you get win7 
home cpu limits and only after updates do you have pro lqarger cpu count 
activated. I may remeber wrong, but I will do that first and report 
back.


> Since I do not have networking sorted out yet I cannot update win7 pro, 
> and it
might be the updates which are needed for allowing more than two cpus.

hm, brief search on my side resulted in this tip:

https://answers.microsoft.com/en-us/windows/forum/windows_7-hardware/windows-7-professional-x64-only-showing-2-of-8/0155f525-df73-4642-a828-21b80d1564b0

----------
Some recommendations (in Windows, make sure you are running as 
Administrator):

- Run MSConfig -> Change to Boot tab -> Advanced Options -> "Number of
Processors", make sure there is no check mark.
- Delete processor entries listed in Device Manager, then reboot.

-------------

(I don't think BIOS options from this answer really apply directly to 
qemu case)

also, if win (or some applications inside it) keep crashing with -cpu 
host, you
can try to reload host (Linux) kvm module with additional option:

"options kvm ignore_msrs=1" line (without quotes) should be added to
  /etc/modprobe.d/kvm.conf

from
https://www.passmark.com/forum/performancetest/4748-startup-error-number-4-on-qemu-bsod