On 10 March 2017 at 09:59, Peter Xu <pet...@redhat.com> wrote:
> On Fri, Mar 10, 2017 at 09:33:57AM +0100, Paolo Bonzini wrote:
>>
>>
>> On 10/03/2017 05:13, Peter Xu wrote:
>> > Trying to get memory region size of an uninitialized memory region is
>> > probably not a good idea. Let's just do the alloc no matter what.
>> >
>> > Signed-off-by: Peter Xu <pet...@redhat.com>
>>
>> What is the effect of the bug? The idea was to do the initialization
>> once only (memory_region_size ought to be 0 when the MR is
>> uninitialized; now it is ugly but it made more sense when MemoryRegion
>> was just a C struct and not a QOM object).
>
> It's not really a bug. I just saw it, thought it was something not
> quite right, so posted a patch.
We could reasonably abstract out the test into a function
bool backend_mr_initialized(HostMemoryBackend *backend)
{
/* We forbid zero-length in file_backend_memory_alloc,
* so zero always means "we haven't allocated the backend
* MR yet".
*/
return memory_region_size(&backend->mr) != 0;
}
and use it in file_backend_memory_alloc(), set_mem_path()
and file_memory_backend_set_share(). That would make the intent
clearer here I think.
thanks
-- PMM
