Re: [Qemu-devel] Re: [PATCH RFC] Mark a device as non-migratable

[Anthony Liguori <anthony@codemonkey.ws>]

On 06/16/2010 12:05 AM, Cam Macdonell wrote:
> On Tue, Jun 15, 2010 at 4:33 PM, Anthony Liguori<anthony@codemonkey.ws>  wrote:
>    
>> On 06/15/2010 05:26 PM, Cam Macdonell wrote:
>>      
>>> On Tue, Jun 15, 2010 at 10:32 AM, Anthony Liguori<anthony@codemonkey.ws>
>>>   wrote:
>>>
>>>        
>>>> On 06/15/2010 11:16 AM, Cam Macdonell wrote:
>>>>
>>>>          
>>>>> How does this look for marking the device as non-migratable?  It adds a
>>>>> field
>>>>> 'no_migrate' to the SaveStateEntry and tests for it in vmstate_save.
>>>>>   This
>>>>> would
>>>>> replace anything that touches memory.
>>>>>
>>>>> Cam
>>>>>
>>>>> ---
>>>>>   hw/hw.h  |    1 +
>>>>>   savevm.c |   32 +++++++++++++++++++++++++++++---
>>>>>   2 files changed, 30 insertions(+), 3 deletions(-)
>>>>>
>>>>> diff --git a/hw/hw.h b/hw/hw.h
>>>>> index d78d814..7c93f08 100644
>>>>> --- a/hw/hw.h
>>>>> +++ b/hw/hw.h
>>>>> @@ -263,6 +263,7 @@ int register_savevm_live(const char *idstr,
>>>>>                            void *opaque);
>>>>>
>>>>>   void unregister_savevm(const char *idstr, void *opaque);
>>>>> +void mark_no_migrate(const char *idstr, void *opaque);
>>>>>
>>>>>
>>>>>            
>>>> I'm not thrilled with the name but the functionality is spot on.  I lack
>>>> the
>>>> creativity to offer a better name suggestion :-)
>>>>
>>>> Regards,
>>>>
>>>> Anthony Liguori
>>>>
>>>>          
>>> Hmmm, in working on this it seems that the memory (from
>>> qemu_ram_map()) is still attached even when the device is removed
>>> (which causes migration to fail because there is an unexpected
>>> memory).
>>>
>>> Is something like cpu_unregister_physical_memory()/qemu_ram_free() needed?
>>>
>>>        
>> Yes.  You need to unregister any memory that you have registered upon device
>> removal.
>>      
> Is there an established way to achieve this?  I can't seem find
> another device that unregisters memory registered with
> cpu_register_physical_memory().  Is something like
> cpu_unregister_physical_memory() needed?
>    

cpu_register_physical_memory(IO_MEM_UNASSIGNED).

If you look at pci.c, you'll see that it automatically unregisters any 
mapped io regions on remove.

Regards,

Anthony Liguori

> Thanks,
> Cam
>
>    
>> Regards,
>>
>> Anthony Liguori
>>
>>      
>>> Cam
>>>
>>>
>>>        
>>
>>