[Qemu-devel] Re: [PATCH 1/6] Make fw_cfg interface 32-bit aware

[Anthony Liguori <anthony@codemonkey.ws>]

Alexander Graf wrote:
> Anthony Liguori wrote:
>   
>> Alexander Graf wrote:
>>     
>>> The fw_cfg interface can only handle up to 16 bits of data for its
>>> streams.
>>> While that isn't too much of a problem when handling integers, we would
>>> like to stream full kernel images over that interface!
>>>
>>> So let's extend it to 32 bit length variables.
>>>
>>> Signed-off-by: Alexander Graf <agraf@suse.de>
>>> ---
>>>  hw/fw_cfg.c |    8 ++++----
>>>  hw/fw_cfg.h |    2 +-
>>>  2 files changed, 5 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/hw/fw_cfg.c b/hw/fw_cfg.c
>>> index a6d811b..3a3f694 100644
>>> --- a/hw/fw_cfg.c
>>> +++ b/hw/fw_cfg.c
>>> @@ -39,7 +39,7 @@
>>>  #define FW_CFG_SIZE 2
>>>  
>>>  typedef struct _FWCfgEntry {
>>> -    uint16_t len;
>>> +    uint32_t len;
>>>      uint8_t *data;
>>>      void *callback_opaque;
>>>      FWCfgCallback callback;
>>> @@ -48,7 +48,7 @@ typedef struct _FWCfgEntry {
>>>  typedef struct _FWCfgState {
>>>      FWCfgEntry entries[2][FW_CFG_MAX_ENTRY];
>>>      uint16_t cur_entry;
>>> -    uint16_t cur_offset;
>>> +    uint32_t cur_offset;
>>>  } FWCfgState;
>>>  
>>>  static void fw_cfg_write(FWCfgState *s, uint8_t value)
>>> @@ -171,12 +171,12 @@ static const VMStateDescription vmstate_fw_cfg = {
>>>      .minimum_version_id_old = 1,
>>>      .fields      = (VMStateField []) {
>>>          VMSTATE_UINT16(cur_entry, FWCfgState),
>>> -        VMSTATE_UINT16(cur_offset, FWCfgState),
>>> +        VMSTATE_UINT32(cur_offset, FWCfgState),
>>>          VMSTATE_END_OF_LIST()
>>>      }
>>>  };
>>>  
>>> -int fw_cfg_add_bytes(void *opaque, uint16_t key, uint8_t *data,
>>> uint16_t len)
>>> +int fw_cfg_add_bytes(void *opaque, uint16_t key, uint8_t *data,
>>> uint32_t len)
>>>  {
>>>      FWCfgState *s = opaque;
>>>      int arch = !!(key & FW_CFG_ARCH_LOCAL);
>>>   
>>>       
>> We need to bump a version here.
>>     
>
> Sure - which one?
>   

The version_id field in vmstate_fw_cfg.  You also have to try to support 
older versions which means you may want to either split cur_offset into 
a high and low or ask Juan what the appropriate vodoo would be.

Regards,

Anthony Liguori

> Alex
>