Re: [Qemu-devel] [PATCH v7 10/13] vfio: Add load state functions to SaveVMHandlers

[Kirti Wankhede <kwankhede@nvidia.com>]

On 7/12/2019 8:22 AM, Yan Zhao wrote:
> On Tue, Jul 09, 2019 at 05:49:17PM +0800, Kirti Wankhede wrote:
>> Flow during _RESUMING device state:
>> - If Vendor driver defines mappable region, mmap migration region.
>> - Load config state.
>> - For data packet, till VFIO_MIG_FLAG_END_OF_STATE is not reached
>>     - read data_size from packet, read buffer of data_size
>>     - read data_offset from where QEMU should write data.
>>         if region is mmaped, write data of data_size to mmaped region.
>>     - write data_size.
>>         In case of mmapped region, write to data_size indicates kernel
>>         driver that data is written in staging buffer.
>>     - if region is trapped, pwrite() data of data_size from data_offset.
>> - Repeat above until VFIO_MIG_FLAG_END_OF_STATE.
>> - Unmap migration region.
>>
>> For user, data is opaque. User should write data in the same order as
>> received.
>>
>> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
>> Reviewed-by: Neo Jia <cjia@nvidia.com>
>> ---
>>  hw/vfio/migration.c  | 162 +++++++++++++++++++++++++++++++++++++++++++++++++++
>>  hw/vfio/trace-events |   3 +
>>  2 files changed, 165 insertions(+)
>>
>> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
>> index 4e9b4cce230b..5fb4c5329ede 100644
>> --- a/hw/vfio/migration.c
>> +++ b/hw/vfio/migration.c
>> @@ -249,6 +249,26 @@ static int vfio_save_device_config_state(QEMUFile *f, void *opaque)
>>      return qemu_file_get_error(f);
>>  }
>>  
>> +static int vfio_load_device_config_state(QEMUFile *f, void *opaque)
>> +{
>> +    VFIODevice *vbasedev = opaque;
>> +    uint64_t data;
>> +
>> +    if (vbasedev->ops && vbasedev->ops->vfio_load_config) {
>> +        vbasedev->ops->vfio_load_config(vbasedev, f);
>> +    }
>> +
>> +    data = qemu_get_be64(f);
>> +    if (data != VFIO_MIG_FLAG_END_OF_STATE) {
>> +        error_report("%s: Failed loading device config space, "
>> +                     "end flag incorrect 0x%"PRIx64, vbasedev->name, data);
>> +        return -EINVAL;
>> +    }
>> +
>> +    trace_vfio_load_device_config_state(vbasedev->name);
>> +    return qemu_file_get_error(f);
>> +}
>> +
>>  /* ---------------------------------------------------------------------- */
>>  
>>  static int vfio_save_setup(QEMUFile *f, void *opaque)
>> @@ -421,12 +441,154 @@ static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
>>      return ret;
>>  }
>>  
>> +static int vfio_load_setup(QEMUFile *f, void *opaque)
>> +{
>> +    VFIODevice *vbasedev = opaque;
>> +    VFIOMigration *migration = vbasedev->migration;
>> +    int ret = 0;
>> +
>> +    if (migration->region.buffer.mmaps) {
>> +        ret = vfio_region_mmap(&migration->region.buffer);
>> +        if (ret) {
>> +            error_report("%s: Failed to mmap VFIO migration region %d: %s",
>> +                         vbasedev->name, migration->region.index,
>> +                         strerror(-ret));
>> +            return ret;
>> +        }
>> +    }
>> +
>> +    ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING);
>> +    if (ret) {
>> +        error_report("%s: Failed to set state RESUMING", vbasedev->name);
>> +    }
>> +    return ret;
>> +}
>> +
>> +static int vfio_load_cleanup(void *opaque)
>> +{
>> +    vfio_save_cleanup(opaque);
>> +    return 0;
>> +}
>> +
>> +static int vfio_load_state(QEMUFile *f, void *opaque, int version_id)
>> +{
>> +    VFIODevice *vbasedev = opaque;
>> +    VFIOMigration *migration = vbasedev->migration;
>> +    int ret = 0;
>> +    uint64_t data, data_size;
>> +
> I think checking of version_id is still needed.
> 

Checking version_id with what value?

Thanks,
Kirti