Re: [PATCH v5 COLOPre 08/18] tools/libxl: introduce libxl__domain_restore_device_model to load qemu state

[Wen Congyang <wency@cn.fujitsu.com>]

On 01/26/2016 02:41 AM, Konrad Rzeszutek Wilk wrote:
> On Thu, Dec 17, 2015 at 03:48:12PM +0800, Wen Congyang wrote:
>> From: Yang Hongyang <hongyang.yang@easystack.cn>
>>
>> In normal migration, the qemu state was passed to qemu as a parameter.
> 
> /was/is/
> 
>> With COLO, Secondary vm is running. So we will do the following steps
>> at every checkpoint:
>> 1. suspend both primary vm and secondary vm
>> 2. sync the state
>> 3. resume both primary vm and secondary vm
>> Primary will send qemu's state in step2, and
>> Secondary's qemu should read it and restore the state before it
> 
> s/Secondary/secondary/
>> is resumed. We can not pass the state to qemu as a parameter because
>> Secondary QEMU already started at this point, so we introduce
> 
> s/Secondary/secondary/
>> libxl__domain_restore_device_model() to do it.
>> This API should be called before resuming secondary vm.
> 
> s/before/MUST/

s/should/MUST/?

Thanks
Wen Congyang

> 
>>
>> Signed-off-by: Yang Hongyang <hongyang.yang@easystack.cn>
>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>> Cc: Anthony Perard <anthony.perard@citrix.com>
>> ---
>>  tools/libxl/libxl_dom_save.c | 20 ++++++++++++++++++++
>>  tools/libxl/libxl_internal.h |  4 ++++
>>  tools/libxl/libxl_qmp.c      | 10 ++++++++++
>>  3 files changed, 34 insertions(+)
>>
>> diff --git a/tools/libxl/libxl_dom_save.c b/tools/libxl/libxl_dom_save.c
>> index 0bfa5fc..88cb1b3 100644
>> --- a/tools/libxl/libxl_dom_save.c
>> +++ b/tools/libxl/libxl_dom_save.c
>> @@ -609,6 +609,26 @@ int libxl__restore_emulator_xenstore_data(libxl__domain_create_state *dcs,
>>      return rc;
>>  }
>>  
>> +int libxl__domain_restore_device_model(libxl__gc *gc, uint32_t domid,
>> +                                       const char *restore_file)
>> +{
>> +    int rc;
>> +
>> +    switch (libxl__device_model_version_running(gc, domid)) {
>> +    case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL:
>> +        /* not supported now */
> 
> Perhaps: Will never be supported.
> 
>> +        rc = ERROR_INVAL;
>> +        break;
>> +    case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN:
>> +        rc = libxl__qmp_restore(gc, domid, restore_file);
>> +        break;
>> +    default:
>> +        rc = ERROR_INVAL;
>> +    }
>> +
>> +    return rc;
>> +}
>> +
> 
> 
> .
>