Add hyper-v timer enlightenments for windows guests

[Daniel Berrange]

Back in Folsom we added some special timer settings to improve the reliability of guest time keeping and performance

  https://bugs.launchpad.net/nova/+bug/1011848

These were useful for both Windows and Linux guests, but since that time, KVM has gained support for a number of further tunables that specifically help Windows guests supporting Hyper-V enlightenments. Setting these for all windows guests will improve time keeping reliability and performance of windows guests. There is no harm to setting them with old windows versions which lack support for this, since they'll simply ignore the extra feature with no negative impact.

The recommended qemu configuration is from QEMU maintainers is:

   -cpu ...,hv_relaxed,hv_spinlocks=0x1fff,hv_vapic,hv_time

Which maps to the libvirt XML:

   <features>
     <hyperv>
       <relaxed state='on'/>
       <vapic state='on'/>
       <spinlocks state='on' retries='8191'/>
     </hyperv>
   <features/>

   <clock ...>
     <timer name='hypervclock' present='yes'/>
   </clock>

Though there are some version caveats here:
- relaxed state='on' libvirt 1.0.0+, qemu 1.1+
- vapic, spinlocks requires libvirt 1.1.0+, qemu 1.1+
- hypervclock requires libvirt 1.2.2+, qemu 2.0.0+

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/140084

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/140085

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/140086

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/140087

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/140088

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/140089

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/140084
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=b6a5b25335fc93bf605de19cd8531380535de666
Submitter: Jenkins
Branch: master

commit b6a5b25335fc93bf605de19cd8531380535de666
Author: Daniel P. Berrange <email address hidden>
Date: Thu Nov 20 12:24:35 2014 +0000

    libvirt: move setting of clock out into helper method

    Move clock settings will be added in the future, so it
    makes sense to have a separate helper method for all
    of them.

    Related-bug: #1400315
    Change-Id: I1662e2d1e2e729da873c14a0cc307e412c699320

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/140085
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=989eac8b748fd6a545198541afa672039e339f90
Submitter: Jenkins
Branch: master

commit 989eac8b748fd6a545198541afa672039e339f90
Author: Daniel P. Berrange <email address hidden>
Date: Thu Nov 20 12:24:55 2014 +0000

    libvirt: add support for hyperv timer source with windows guests

    The hyperv timer source enables Windows guests to keep accurate
    time, much like kvmclock does for Linux guests. It should be
    enabled for all windows guests, as it doesn't harm older windows
    versions which don't know about it.

    Related-bug: #1400315
    Change-Id: I6af05b4e8e0b2145733c0f301c04555da23b7da8

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/140086
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=3afdc2a2b0ba7c558d51a53096a97bf2ba3640ce
Submitter: Jenkins
Branch: master

commit 3afdc2a2b0ba7c558d51a53096a97bf2ba3640ce
Author: Daniel P. Berrange <email address hidden>
Date: Mon Dec 8 13:11:18 2014 +0000

    libvirt: change representation of guest features

    While the current acpi, apic & pae features are mere single elements,
    further feature will require complex data structures. The libvirt
    config class must thus change from using a simple string to represent
    a feature, to a full class

    Related-bug: #1400315
    Change-Id: Ia6fa2602dd7a9e7623abcfd46c8b57d3631372ef

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/140087
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=189b682ff3dcca38e5b19b52144c3eb4c9bbabbe
Submitter: Jenkins
Branch: master

commit 189b682ff3dcca38e5b19b52144c3eb4c9bbabbe
Author: Daniel P. Berrange <email address hidden>
Date: Mon Dec 8 13:49:01 2014 +0000

    libvirt: add support for configuring hyperv enlightenments in XML

    Extend the guest XML config classes to cope with the following
    hyperv enlightenments:

       <features>
         <hyperv>
           <relaxed state='on'/>
           <vapic state='on'/>
           <spinlocks state='on' retries='4095'/>
         </hyperv>
       <features/>

    Related-bug: #1400315
    Change-Id: Ieff2ae44bf90e09152a56859709707ccdf83cbc9

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/140088
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=31d91d9de312409850f29fcac7f142c3fe7c956f
Submitter: Jenkins
Branch: master

commit 31d91d9de312409850f29fcac7f142c3fe7c956f
Author: Daniel P. Berrange <email address hidden>
Date: Mon Dec 8 13:55:45 2014 +0000

    libvirt: move setting of guest features out into helper method

    Move guest features into a separate helper method, since there
    will be more complicated guest features to be set in the guest
    config in the future.

    Related-bug: #1400315
    Change-Id: Icf575ab1d6eb2a011c08efd998997d0d82aa15a6

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/140089
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=12cf893fd9bc787d2c5c6ef0a8ca0f81582ead8a
Submitter: Jenkins
Branch: master

commit 12cf893fd9bc787d2c5c6ef0a8ca0f81582ead8a
Author: Daniel P. Berrange <email address hidden>
Date: Mon Dec 8 14:30:06 2014 +0000

    libvirt: enable hyperv enlightenments for windows guests

    All windows guests (ie os_type=windows) now get the following
    enabled

           <features>
             <hyperv>
               <relaxed state='on'/>
               <vapic state='on'/>
               <spinlocks state='on' retries='8191'/>
             </hyperv>
           <features/>

    if running a new enough libvirt and QEMU

    Closes-bug: #1400315
    Change-Id: Icd0fe9bda6402d9bf7a4bab8077f0ce755703999