Bug 1094820

Summary:	Hot plug CPU not working with RHEL6 machine types running on RHEL7 host.
Product:	Red Hat Enterprise Linux 7	Reporter:	Jan Kurik <jkurik>
Component:	qemu-kvm	Assignee:	Miroslav Rezanina <mrezanin>
Status:	CLOSED ERRATA	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	high	Docs Contact:
Priority:	unspecified
Version:	7.0	CC:	acathrow, areis, gklein, hhuang, iheim, imammedo, jherrman, jkurik, juzhang, knoel, lersek, lpeer, michal.skrivanek, michen, mkalinin, mrezanin, nsednev, pbonzini, pm-eus, qzhang, Rhev-m-bugs, virt-maint, xfu, yeylon
Target Milestone:	rc	Keywords:	ZStream
Target Release:	---
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:	qemu-kvm-1.5.3-60.el7_0.2	Doc Type:	Bug Fix
Doc Text:	Previously, an internal error prevented KVM from executing a CPU hot plug on a Red Hat Enterprise Linux 7 guest running on a Red Hat Enterprise Linux 7 host. This update addresses the internal error and CPU hot plugging in the described scenario now functions correctly.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2014-06-10 12:35:17 UTC	Type:	---
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:	1094285
Bug Blocks:

Description Jan Kurik 2014-05-06 14:35:36 UTC

This bug has been copied from bug #1094285 and has been proposed
to be backported to 7.0 z-stream (EUS).

Comment 5 FuXiangChun 2014-05-08 15:02:04 UTC

QE tested this bug with qemu-kvm-1.5.3-60.el7_0.2.x86_64 and 3.10.0-123.el7.x86_64

Tested two scenarios.

S1. For RHEL6.5 & win2012 & rhel7.0 guest
Boot guest with machine type rhel6.0.0 ~ rhel6.5.0 & pc on rhel7.0 host

result:
hotplug vcpu->works

S2. For RHEL6.5 & win2012 guest.
1.Boot guest with machine type rhel6.0.0 ~ rhel6.5.0 on rhel6.6 host.
2.migration from rhel6.6 -> rhel7.0 
3.hotplug vcpu on rhel7.0

result:
hotplug vcpu->works

so, Base on this testing result. This bug is fixed.


additional.
For rhel6.6 host.
# uname -r
2.6.32-459.el6.x86_64
qemu-kvm-0.12.1.2-2.425.el6.x86_64

Comment 6 FuXiangChun 2014-05-09 01:38:20 UTC

Jan,
As far as QE know, we support vcpu hotplug from rhel6.3. Current, according to my testing result as comment5. vcpu can be hotpluged successfully with -M RHEL6.0~6.2 as well, It is expected?

Comment 7 juzhang 2014-05-09 01:40:18 UTC

Seems we need to needinfo paolo.

Comment 8 Karen Noel 2014-05-09 11:32:22 UTC

There are 3 components: host, machine type and guest OS

1. KVM supports vcpu inplug starting with RHEL 6.4 host. (6.3 was tech preview)

2. Any rhel6.y.0 machine type can be used. 

3. Any guest OS that supports CPU hotplug will work.

So, the RHEL7 behavior matches RHEL6. 

Thanks.

Comment 13 errata-xmlrpc 2014-06-10 12:35:17 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHSA-2014-0704.html