Re: VM save/restore

[Junjie Wei <junjie.wei@oracle.com>]

On 08/18/2012 03:34 AM, Keir Fraser wrote:
> On 18/08/2012 07:38, "Keir Fraser" <keir.xen@gmail.com> wrote:
>
>>
>>> I think if a VM can be successfully started, then save/restore should
>>> also work. So I made a patch and did some testing.
>>
>> The check for 64 VCPUs is to cover the fact we only save/restore a 64-bit
>> vcpumap. That would need fixing too surely, ot CPUs > 64 would be offline
>> after restore I would imagine.
>
> How about the attached patch? It might actually work properly, unlike yours.
> ;)
>
>>> The above problem is gone but there are new ones.
>>>
>>> Let me summarize the result here.
>>>
>>> With the patch, save/restore works fine as long as it can be started,
>>> except two cases.
>>>
>>> 1) 32-bit guests can be configured with VCPUs > 32 and started,
>>>      but the guest can only make use of 32 of them.
>
> HVM guest? I don't know why this is. You will have to investigate some more
> what has happened to the rest of your VCPUs! I think it should definitely
> work. Cc Jan in case he has any thoughts.
>
>>> 2) 32-bit PVM guests can be configured with VCPUs > 64 and started,
>>>      but `xm save' does not work.
>
> That's because your changes to the save/restore code were wrong. Try my
> patch instead.
>
>   -- Keir
>

Tested. Your patch works perfectly for all cases. :)


Thanks,
Junjie