Re: [PATCH v2 1/1] hw/nvram: Always register FW_CFG_DATA_GENERATOR_INTERFACE

[Philippe Mathieu-Daudé]

On 10/6/20 2:55 PM, Laszlo Ersek wrote:
> On 10/06/20 13:19, Philippe Mathieu-Daudé wrote:
>> While the FW_CFG_DATA_GENERATOR_INTERFACE is only consumed
>> by a device only available using system-mode (fw_cfg), it is
>> implemented by a crypto component (tls-cipher-suites) which
>> is always available when crypto is used.
>>
>> Commit 69699f3055 introduced the following error in the
>> qemu-storage-daemon binary:
>>
>>   $ echo -e \
>>     '{"execute": "qmp_capabilities"}\r\n{"execute": 
>> "qom-list-types"}\r\n{"execute": "quit"}\r\n' \
>>     | storage-daemon/qemu-storage-daemon --chardev stdio,id=qmp0  --monitor 
>> qmp0
>>   {"QMP": {"version": {"qemu": {"micro": 50, "minor": 1, "major": 5}, 
>> "package": ""}, "capabilities": ["oob"]}}
>>   {"return": {}}
>>   missing interface 'fw_cfg-data-generator' for object 'tls-creds'
>>   Aborted (core dumped)
>>
>> Since QOM dependencies are resolved at runtime, this issue
>> could not be triggered at linktime, and we don't have test
>> running the qemu-storage-daemon binary.
>>
>> Fix by always registering the QOM interface.
>>
>> Reported-by: Kevin Wolf <kwolf@redhat.com>
>> Fixes: 69699f3055 ("crypto/tls-cipher-suites: Produce fw_cfg consumable 
>> blob")
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> ---
>>  hw/nvram/fw_cfg-interface.c | 15 +++++++++++++++
>>  hw/nvram/fw_cfg.c           |  7 -------
>>  MAINTAINERS                 |  2 +-
>>  hw/nvram/meson.build        |  3 +++
>>  4 files changed, 19 insertions(+), 8 deletions(-)
>>  create mode 100644 hw/nvram/fw_cfg-interface.c
>>
>> diff --git a/hw/nvram/fw_cfg-interface.c b/hw/nvram/fw_cfg-interface.c
>> new file mode 100644
>> index 0000000000..2b19502ffe
>> --- /dev/null
>> +++ b/hw/nvram/fw_cfg-interface.c
>> @@ -0,0 +1,15 @@
>> +#include "qemu/osdep.h"
>> +#include "hw/nvram/fw_cfg.h"
>> +
>> +static const TypeInfo fw_cfg_data_generator_interface_info = {
>> +    .parent = TYPE_INTERFACE,
>> +    .name = TYPE_FW_CFG_DATA_GENERATOR_INTERFACE,
>> +    .class_size = sizeof(FWCfgDataGeneratorClass),
>> +};
>> +
>> +static void fw_cfg_register_types(void)
>> +{
>> +    type_register_static(&fw_cfg_data_generator_interface_info);
>> +}
>> +
>> +type_init(fw_cfg_register_types)
> 
> Can you rename *this* instance of "fw_cfg_register_types" to
> "fw_cfg_register_interfaces"?
> 
> While the code is correct from the C lang perspective, duplicate
> function names are not convenient when debugging with gdb, or when
> jumping to tags in an editor.

Sure.

> 
> With the rename:
> 
> Reviewed-by: Laszlo Ersek <lersek@redhat.com>

Thanks!

> 
> (If you strongly disagree, I'm OK to R-b v2 as well.)
> 
> Thanks,
> Laszlo
> 
>> diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
>> index 0e95d057fd..08539a1aab 100644
>> --- a/hw/nvram/fw_cfg.c
>> +++ b/hw/nvram/fw_cfg.c
>> @@ -1360,18 +1360,11 @@ static const TypeInfo fw_cfg_mem_info = {
>>      .class_init    = fw_cfg_mem_class_init,
>>  };
>>  
>> -static const TypeInfo fw_cfg_data_generator_interface_info = {
>> -    .parent = TYPE_INTERFACE,
>> -    .name = TYPE_FW_CFG_DATA_GENERATOR_INTERFACE,
>> -    .class_size = sizeof(FWCfgDataGeneratorClass),
>> -};
>> -
>>  static void fw_cfg_register_types(void)
>>  {
>>      type_register_static(&fw_cfg_info);
>>      type_register_static(&fw_cfg_io_info);
>>      type_register_static(&fw_cfg_mem_info);
>> -    type_register_static(&fw_cfg_data_generator_interface_info);
>>  }
>>  
>>  type_init(fw_cfg_register_types)
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index b76fb31861..a45d908ebd 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -2054,7 +2054,7 @@ R: Laszlo Ersek <lersek@redhat.com>
>>  R: Gerd Hoffmann <kraxel@redhat.com>
>>  S: Supported
>>  F: docs/specs/fw_cfg.txt
>> -F: hw/nvram/fw_cfg.c
>> +F: hw/nvram/fw_cfg*.c
>>  F: stubs/fw_cfg.c
>>  F: include/hw/nvram/fw_cfg.h
>>  F: include/standard-headers/linux/qemu_fw_cfg.h
>> diff --git a/hw/nvram/meson.build b/hw/nvram/meson.build
>> index 1f2ed013b2..fd2951a860 100644
>> --- a/hw/nvram/meson.build
>> +++ b/hw/nvram/meson.build
>> @@ -1,3 +1,6 @@
>> +# QOM interfaces must be available anytime QOM is used.
>> +qom_ss.add(files('fw_cfg-interface.c'))
>> +
>>  softmmu_ss.add(files('fw_cfg.c'))
>>  softmmu_ss.add(when: 'CONFIG_CHRP_NVRAM', if_true: files('chrp_nvram.c'))
>>  softmmu_ss.add(when: 'CONFIG_DS1225Y', if_true: files('ds1225y.c'))
>>
>