[ovirt-users] ovirt 4.1 - skylake - no avx512 support in virtual machines

[Marco Lorenzo Crociani]

Hi,
I can't access avx512* instruction set from virtual machines.
I have made a one server compute cluster to test new hardware:

oVirt 4.1.9
CentOS 7
Cluster CPU Type: Intel Skylake Family
Compatibility Version: 4.1

HOST:
CPU Model Name:Intel(R) Xeon(R) Platinum 8180 CPU @ 2.50GHz
Family: Family
CPU Type: Intel Skylake Family

Virtual Machine settings
A) VM:
Custom CPU Type: Use cluster default(Intel Skylake Family)
General Tab shows: Guest CPU Type: Skylake-Client

avx512: NO

B) VM:
Custom CPU Type: Skylake-Client
General Tab shows: Guest CPU Type: Skylake-Client

avx512: NO

C) VM:
Custom CPU Type: Use cluster default(Intel Skylake Family) [grey - 
cannot modify]
Migration mode: Do not allow migration
Pass-Through Host CPU
General Tab shows: Guest CPU Type: Skylake-Client

avx512: YES   ( cat /proc/cpuinfo  |grep avx512: avx512f avx512dq 
avx512cd avx512bw avx512vl )

Using pass-through host cpu (disabling vm migration) is the only way to 
access avx512 in a VM, is it a bug or am I missing something?

Regards,

-- 
Marco Crociani
Prisma Telecom Testing S.r.l.
via Petrocchi, 4  20127 MILANO  ITALY
Phone:  +39 02 26113507
Fax:  +39 02 26113597
e-mail:  marcoc at prismatelecomtesting.com
web:  http://www.prismatelecomtesting.com