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Date: Mon, 14 Nov 2011 13:55:34 -0600
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [PATCH 2/7] ivshmem: use migration blockers to
 prevent live	migration in peer mode
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To: quintela@redhat.com
Cc: Kevin Wolf <kwolf@redhat.com>, Lucas Meneghel Rodrigues <lmr@redhat.com>, Anthony Liguori <aliguori@us.ibm.com>, Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>, qemu-devel@nongnu.org, Avi Kivity <avi@redhat.com>

On 11/14/2011 01:52 PM, Juan Quintela wrote:
> Anthony Liguori<aliguori@us.ibm.com>  wrote:
>> On 11/14/2011 07:05 AM, Juan Quintela wrote:
>>> Anthony Liguori<aliguori@us.ibm.com>   wrote:
>>>> Now when you try to migrate with ivshmem, you get a proper QMP error:
>>>>
>>>> (qemu) migrate tcp:localhost:1025
>>>> Migration is disabled when using feature 'peer mode' in device 'ivshmem'
>>>> (qemu)
>>>
>>> This was the only user of register_device_unmigratable(), just to remove
>>> function if we continue this path.
>>
>> There are a couple more in usb also but I can convert them too.
>
> usb uses "yet another" way to make devices unmigratable.
>
> static const VMStateDescription vmstate_usb_host = {
>      .name = "usb-host",
>      .unmigratable = 1,
> };
>
> So, we have "already" two ways to make a device unmigratable:
> - calling register_device_unmigratable() (ivhs)
> - definining in vmstate .unmigratable = 1
> - and now your new way.
>
> My point was that only one (or even two) should be enough.

Ah, yes, I see now.  I'll remove that function.

Regards,

Anthony Liguori

>
> Why two? because the .unmigratable way is very useful for devices that
> haven't been made "migratable", but that are converted to qdev.  Not
> jthat this couldn't be "fixed" on registration with a call to
> migrate_add_blocker.
>
> Later, Juan.
>