Re: [PATCH 4/6] hw/dma: Replace alloc() + address_space_init() by address_space_create()

[Philippe Mathieu-Daudé]

On 8/19/21 4:22 PM, Peter Maydell wrote:
> On Thu, 19 Aug 2021 at 15:21, Philippe Mathieu-Daudé <philmd@redhat.com> 
> wrote:
>>
>> Replace g_malloc0() + address_space_init() by address_space_create().
>> Release the resource in DeviceUnrealize().
>>
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> ---
>>  hw/dma/xlnx-zdma.c    | 15 +++++++++------
>>  hw/dma/xlnx_csu_dma.c |  9 ++-------
>>  2 files changed, 11 insertions(+), 13 deletions(-)
>>
>> diff --git a/hw/dma/xlnx-zdma.c b/hw/dma/xlnx-zdma.c
>> index fa38a556341..9f6b3fa47c6 100644
>> --- a/hw/dma/xlnx-zdma.c
>> +++ b/hw/dma/xlnx-zdma.c
>> @@ -777,15 +777,17 @@ static void zdma_realize(DeviceState *dev, Error 
>> **errp)
>>          };
>>      }
>>
>> -    if (s->dma_mr) {
>> -        s->dma_as = g_malloc0(sizeof(AddressSpace));
>> -        address_space_init(s->dma_as, s->dma_mr, NULL);
>> -    } else {
>> -        s->dma_as = &address_space_memory;
>> -    }
>> +    s->dma_as = address_space_create(s->dma_mr ?: get_system_memory(), 
>> NULL);
>>      s->attr = MEMTXATTRS_UNSPECIFIED;
>>  }
> 
> Why are these devices doing a heap allocation rather than
> having an AddressSpace whatever field in their device struct ?

To easily use &address_space_memory if 'memory' link is NULL?