[libvirt] [PATCH 3/4] PowerPC cpu : Handle only high order 16 bits for PVR

[Daniel P. Berrange]

On Fri, Oct 10, 2014 at 03:51:22PM +0530, Prerna Saxena wrote:
> 
> >From 1bcba78ed387a876208fec1ef60b81d65c8474e5 Mon Sep 17 00:00:00 2001
> From: "Pradipta Kr. Banerjee" <bpradip at in.ibm.com>
> Date: Tue, 7 Oct 2014 11:12:36 +0530
> 
> IBM Power processors differ uniquely across generations (such as power6,
> power7, power8). Each generation signifies a new PowerISA version
> that exhibits features unique to that generation.
> The higher 16 bits of PVR for IBM Power processors encode the CPU generation,
> while the CPU chip (sub)version is encoded in lower 16 bits.
> 
> For all practical purposes of launching a VM, we care about the
> generation which the vCPU will belong to, and not specifically the chip
> version. This patch updates the libvirt PVR check to reflect this
> relationship.
> It also contains changes to cpu_map.xml since processor generations
> as understood by QEMU compat mode go as "power6", "power7" or "power8"
> [Reference : QEMU commit 8dfa3a5e85 ]
> 
> Signed-off-by: Pradipta Kr. Banerjee <bpradip at in.ibm.com>
> Signed-off-by: Prerna Saxena <prerna at linux.vnet.ibm.com>
> ---
>  src/cpu/cpu_map.xml   | 22 ++++++++--------------
>  src/cpu/cpu_powerpc.c |  7 ++++++-
>  2 files changed, 14 insertions(+), 15 deletions(-)
> 
> diff --git a/src/cpu/cpu_map.xml b/src/cpu/cpu_map.xml
> index 18c7b0d..f2f13fb 100644
> --- a/src/cpu/cpu_map.xml
> +++ b/src/cpu/cpu_map.xml
> @@ -602,30 +602,24 @@
>      <vendor name='IBM'/>
>  
>      <!-- IBM-based CPU models -->
> -    <model name='POWER7'>
> +    <model name='power6'>
>        <vendor name='IBM'/>
> -      <pvr value='0x003f0200'/>
> +      <pvr value='0x003e0000'/>
>      </model>
>  
> -    <model name='POWER7_v2.1'>
> +    <model name='power7'>
>        <vendor name='IBM'/>
> -      <pvr value='0x003f0201'/>
> +      <pvr value='0x003f0000'/>
>      </model>
>  
> -    <model name='POWER7_v2.3'>
> +    <model name='power7+'>
>        <vendor name='IBM'/>
> -      <pvr value='0x003f0203'/>
> +      <pvr value='0x004a0000'/>
>      </model>
>  
> -    <model name='POWER7+_v2.1'>
> +    <model name='power8'>
>        <vendor name='IBM'/>
> -      <pvr value='0x004a0201'/>
> +      <pvr value='0x004b0000'/>
>      </model>
> -
> -    <model name='POWER8_v1.0'>
> -      <vendor name='IBM'/>
> -      <pvr value='0x004b0100'/>
> -    </model>
> -
>    </arch>
>  </cpus>

This looks like it is going to break upgrades for any existing deployed
guests on PPC using named CPU models, which is not something we can do.

Regards,
Daniel
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