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[libvirt] [PATCH v1 0/3] libvirt: Implement CPU model driver for PowerPC



CPU model driver is to get host's CPU information and it also provides 
one mechanism to expose host's CPU information to guests during migration.

When migrating one guest from one machine to another machine, it will
compare the CPU information. If it is incomptible, it won't start the
guest.

On x86, it uses CPUID instruction to get information. When migrating
the guest, if the CPU defined in guest XML file is incompatible with
host CPU, cpu-baseline will find out best features to expose to guest.
Refer to
 [http://berrange.com/posts/2010/02/15
  /guest-cpu-model-configuration-in-libvirt-with-qemukvm/].

On PowerPC, it can get CPU version by mfpvr instruction. So, if PVR is
 different from definition in guest XML file by cpu-compare, it will fail
to start guest. The CPU infromation can be got by cpu-baseline. But only
CPU vendor and model can be shown, there are no features as x86.
So on PowrePC, it assumes that migration only occurs between the machines
with the same type CPUs on PowerPC.

In this driver, there are definitions of models and PVRs for CPUs supported
on PowerPC. The relationship between models and PVRs are as the following:
For one specific CPU model, its PVR is unique. And also for one PVR code, 
the PVR code is also unique.

So from the PVR code of CPU data, it's easy to get model and vendor information.

It is tested on my Power machine which CPU PVR is Power7_v2.3.
 * cap.xml has the same definition as the host.
   [root ltckvmopal2 kvm-test]# /bin/virsh cpu-compare cap.xml
   CPU described in cap.xml is identical to host CPU

   [root ltckvmopal2 kvm-test]# /bin/virsh cpu-baseline cap.xml
   <cpu mode='custom' match='exact'>
    <model fallback='allow'>POWER7_v2.3</model>
    <vendor>IBM</vendor>
   </cpu>

 * cap.xml has differnt model as the host.
   [root ltckvmopal2 kvm-test]# /bin/virsh cpu-compare cap.xml
   CPU described in cap.xml is incompatible with host CPU

   [root ltckvmopal2 kvm-test]# /bin/virsh cpu-baseline cap.xml
   <cpu mode='custom' match='exact'>
     <model fallback='allow'>POWER7_v2.1</model>
     <vendor>IBM</vendor>
   </cpu>

 *v1 -> v2:
   * Fix coding style's problems in several places.
   * Seperate doc-fix from the coding

Li Zhang (3):
  libvirt: Add one file cpu_ppc_data.h to define CPU data for PPC
  libvirt: Implement CPU model driver for PowerPC
  Doc-fix for PowerPC CPU model driver

 src/cpu/cpu.h          |    3 +
 src/cpu/cpu_map.xml    |   14 ++
 src/cpu/cpu_powerpc.c  |  589 ++++++++++++++++++++++++++++++++++++++++++++++--
 src/cpu/cpu_ppc_data.h |   33 +++
 4 files changed, 621 insertions(+), 18 deletions(-)
 create mode 100644 src/cpu/cpu_ppc_data.h

-- 
1.7.7.6


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