Bug 1150418

Summary: Intel Westmere missing feature pclmulqdq(pclmuldq) in guests
Product: Red Hat Enterprise Linux 6 Reporter: mlinden
Component: libvirtAssignee: Libvirt Maintainers <libvirt-maint>
Status: CLOSED DUPLICATE QA Contact: Virtualization Bugs <virt-bugs>
Severity: medium Docs Contact:
Priority: medium    
Version: 6.0CC: ecohen, gklein, iheim, jdenemar, lpeer, lsurette, michal.skrivanek, mlinden, ofrenkel, rbalakri, Rhev-m-bugs, smelamud, yeylon
Target Milestone: pre-dev-freeze   
Target Release: ---   
Hardware: x86_64   
OS: Unspecified   
Whiteboard: virt
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2015-04-14 10:54:48 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1150417    
Bug Blocks:    

Description mlinden 2014-10-08 09:03:59 UTC
Description of problem:

The feature pclmulqdq (also called pclmuldq ) was introduced in Intel Westmere:
http://en.wikipedia.org/wiki/Westmere_%28microarchitecture%29

It is visible on the hypervisor but not on guests.
According to kbase: https://access.redhat.com/solutions/634853 it was introduced in libvirt on Sandybridge. 

Also according to the  /usr/share/libvirt/cpu_map.xml file on the hypervisor it was introduced on Sandybridge, but not Westmere.
Seems like libvirt is missing this cpu feature for Westmere.


Version-Release number of selected component (if applicable):


How reproducible:
Every time

Steps to Reproduce:
1. On a Westmere cpu setup a guest.
2.  on the guest check /proc/cpuinfo and the pclmulqdq feature is missing
3.

Actual results:
pclmulqdq is missing from /proc/cpuinfo on guests.


Expected results:
pclmulqdq feateure to be in /proc/cpuinfo

Additional info:
The feature works fine if using a Sandybridge CPU.

Comment 1 Michal Skrivanek 2014-10-30 15:29:08 UTC
seems it needs new machine type, moving to 3.6 (at least)

Comment 2 Michal Skrivanek 2014-10-30 15:30:22 UTC
possible workaround is to use vdsm hooks to add the new flag explicitly (taking the risk that if the hook is not deployed on all hosts in cluster it's going to break)

Comment 6 Omer Frenkel 2015-04-14 06:41:49 UTC
sounds like libvirt should map this capability for the correct cpu type?

Comment 8 Jiri Denemark 2015-04-14 10:54:48 UTC

*** This bug has been marked as a duplicate of bug 1150417 ***