Re: [Qemu-ppc] [RFC PATCH] target-ppc: enable migration within the same CPU family

[Alexey Kardashevskiy]

On 04/04/2014 11:28 PM, Alexander Graf wrote:
> On 04/04/2014 07:17 AM, Alexey Kardashevskiy wrote:
>> On 03/24/2014 04:28 PM, Alexey Kardashevskiy wrote:
>>> Currently only migration fails if CPU version is different even a bit.
>>> For example, migration from POWER7 v2.0 to POWER7 v2.1 fails because of
>>> that. Since there is no difference between CPU versions which could
>>> affect migration stream, we can safely enable it.
>>>
>>> This adds a helper to find the closest POWERPC family class (i.e. first
>>> abstract class in hierarchy).
>>>
>>> This replaces VMSTATE_UINTTL_EQUAL statement with a custom handler which
>>> checks if the source and destination CPUs belong to the same family and
>>> fails if they are not.
>>>
>>> This adds a PVR reset to the default value as it will be overwritten
>>> by VMSTATE_UINTTL_ARRAY(env.spr, PowerPCCPU, 1024).
>>>
>>> Since the actual migration format is not changed by this patch,
>>> @version_id of vmstate_ppc_cpu does not have to be changed either.
>>>
>>> Signed-off-by: Bharata B Rao <address@hidden>
>>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
>>
>> Ping?
> 
> Can't we just always allow migration to succeed? It's a problem of the tool
> stack above if it allows migration to an incompatible host, no?

After very convincing mail from Peter Maydell, this is the only solution,
correct? If so, I'll make a patch then.


-- 
Alexey