Description of problem:

Bug 745717 disabled exporting SEP to guest CPUs for RHEL 6.4 (machine types) and below. Bug 821741 is tracking a change to enable it back on RHEL 6.5 machine types since the corresponding kernel bug 821463 has since been fixed. We should have similar behavior for RHEL6 machine types in RHEL7 as well.

Adding additional comments from bug 821741 for context since bugzilla won't let me clone that bug :

SEP flag was so far disabled in RHEL 6 64 bit hosts , it is planned to be fixed.
Migration from host with SEP to host without SEP will fail for 32bit guests.
We need to disable SEP for machine type older than rhel6.4.0
Additional info:

--- Additional comment from Eduardo Habkost on 2012-10-08 17:39:29 EDT ---

Changing summary for clarity.

SEP was disabled as part of the fix for Bug 745717 (making migration work properly). This bug is about enabling the feature on hosts that have the SEP feature enabled.

--- Additional comment from Eduardo Habkost on 2012-11-27 12:44:19 EST ---

*** Bug 880090 has been marked as a duplicate of this bug. ***

--- Additional comment from Eduardo Habkost on 2012-11-27 12:47:55 EST ---

Please try to reproduce bug 880090 using only 6.3.z packages, to confirm this is not a regression.

--- Additional comment from Geyang Kong on 2012-11-28 04:30:13 EST ---

This bug can be reproduced by 6.3.z packages

libvirt-0.9.10-21.el6_3.6.x86_64
qemu-kvm-0.12.1.2-2.295.el6_3.2.x86_64
kernel-2.6.32-279.14.1.el6.x86_64

--- Additional comment from Mike Cao on 2012-12-25 02:49:14 EST ---

snip from Bug 880090

>Eduardo Habkost 2012-11-28 01:25:02 CST
>I could reproduce the issue using qemu-kvm-0.12.1.2-2.316.el6.x86_64, running >kernel 2.6.32-279.el6.x86_64 on the host, so it doesn't seem to be a regression.


What you did it hitting https://bugzilla.redhat.com/show_bug.cgi?id=832301 ,we should reproduce it on the kernel higher than build 307 instead of using 279.

According to sluo's report in https://bugzilla.redhat.com/show_bug.cgi?id=880090
qemu-kvm-0.12.1.2-2.320 + SandyBridge -------> fail
qemu-kvm-0.12.1.2-2.319 + SandyBridge -------> pass

This is a regression bug from build qemu-kvm-320 

move the product flag to rhel6.4.0 .

Mike

--- Additional comment from Ademar de Souza Reis Jr. on 2013-01-02 16:13:07 EST ---

Clarifiying a few issues, please correct me if I'm wrong:

The MS certifications is about the drivers only, not the hypervisor configuration, so we should be fine in adding -cpu ... +sep to qemu cmd line

The problem affects only 32bits versions of win8 (SEP is not used in 64bits mode).

So, the impact of this bug is:

 - win8 32 bit won't boot out of the box
 - it won't affect certification of the drivers
 - win2k12 is x64 only, so it's not affected

--- Additional comment from juzhang on 2013-01-04 00:48:19 EST ---

(In reply to comment #15)
> Clarifiying a few issues, please correct me if I'm wrong:
> 
> The MS certifications is about the drivers only, not the hypervisor
> configuration, so we should be fine in adding -cpu ... +sep to qemu cmd line
> 
> The problem affects only 32bits versions of win8 (SEP is not used in 64bits
> mode).
Does libvirt or rhelm will boot guest with +sep by default? If no, seems need to file separate against libvirt and rhelm.

--- Additional comment from Eduardo Habkost on 2013-01-04 04:27:21 EST ---

(In reply to comment #16)
> (In reply to comment #15)
> > Clarifiying a few issues, please correct me if I'm wrong:
> > 
> > The MS certifications is about the drivers only, not the hypervisor
> > configuration, so we should be fine in adding -cpu ... +sep to qemu cmd line
> > 
> > The problem affects only 32bits versions of win8 (SEP is not used in 64bits
> > mode).
> Does libvirt or rhelm will boot guest with +sep by default? If no, seems
> need to file separate against libvirt and rhelm.

They don't, but this is why this is a qemu-kvm bug, not a libvirt bug. They (correctly) do not expect +sep to be necessary as SEP is supposed to be included in the predefined CPU models.

--- Additional comment from Alves on 2013-02-01 11:02:06 EST ---

I am affected by this bug. Is there work around with RHEL 6.3 under the current kernel 2.6.32-279.19.1.el6.x86_64 ? I can upgrade to a beta version of the kernel if necessary. Please advise.

--- Additional comment from Alves on 2013-02-04 01:45:55 EST ---

Dear Gentlemen, please raise alert. I installed a server with Beta 6.4, and the bug is still there. I tried also forcing NX and SEP, but the same issue. So this is not fixed. I can give access to Redhat engineer to my system via VNC, so he may see the problem.
Should I open a new bug or we may continue here??

If we don't fix KVM, the enterprise is going ignore it.

--- Additional comment from Mike Cao on 2013-02-04 02:05:03 EST ---

(In reply to comment #19)
> Dear Gentlemen, please raise alert. I installed a server with Beta 6.4, and
> the bug is still there. I tried also forcing NX and SEP, but the same issue.
> So this is not fixed. I can give access to Redhat engineer to my system via
> VNC, so he may see the problem.
> Should I open a new bug or we may continue here??
> 
> If we don't fix KVM, the enterprise is going ignore it.

I can not reproduce your issue w/ 2.6.32-338.el6.x86_64 & qemu-kvm-rhev-0.12.1.2-2.331.el6.x86_64 /

Pls provide your qemu-kvm commandline,qemu-kvm(-rhev) & kernel version