Re: [Qemu-devel] [PATCH v2 05/14] exec.c: Convert subpage memory ops to _with_attrs

[Peter Maydell]

On 17 April 2015 at 17:15, Alex Bennée <address@hidden> wrote:
>
> Peter Maydell <address@hidden> writes:
>
>> Convert the subpage memory ops to _with_attrs; this will allow
>> us to pass the attributes through to the underlying access
>> functions. (Nothing uses the attributes yet.)
>>
>> Signed-off-by: Peter Maydell <address@hidden>
>> Reviewed-by: Paolo Bonzini <address@hidden>
>> Reviewed-by: Edgar E. Iglesias <address@hidden>
>> ---
>>  exec.c | 33 +++++++++++++++++++++------------
>>  1 file changed, 21 insertions(+), 12 deletions(-)
>>
>> diff --git a/exec.c b/exec.c
>> index 34dafd2..bba6f26 100644
>> --- a/exec.c
>> +++ b/exec.c
>> @@ -1941,8 +1941,8 @@ static const MemoryRegionOps watch_mem_ops = {
>>      .endianness = DEVICE_NATIVE_ENDIAN,
>>  };
>>
>> -static uint64_t subpage_read(void *opaque, hwaddr addr,
>> -                             unsigned len)
>> +static MemTxResult subpage_read(void *opaque, hwaddr addr, uint64_t *data,
>> +                                unsigned len, MemTxAttrs attrs)
>>  {
>>      subpage_t *subpage = opaque;
>>      uint8_t buf[8];
>> @@ -1951,23 +1951,29 @@ static uint64_t subpage_read(void *opaque, hwaddr 
>> addr,
>>      printf("%s: subpage %p len %u addr " TARGET_FMT_plx "\n", __func__,
>>             subpage, len, addr);
>>  #endif
>> -    address_space_read(subpage->as, addr + subpage->base, buf, len);
>> +    if (address_space_read(subpage->as, addr + subpage->base, buf, len)) {
>> +        return MEMTX_DECODE_ERROR;
>> +    }
>
> Doesn't this mean we loose potential other error bits that are returned
> by address_space_read()? Would MEMTX_ERROR ever potentially be returned?

At this point in the series address_space_read() returns a bool.
In the next patch we change the return type of address_space_read()
and this code is also changed to match (ie it returns the error
value).

-- PMM