Il 14/10/2014 07:42, Peter Maydell ha scritto:
> On 14 October 2014 07:10, Paolo Bonzini <pbonz...@redhat.com> wrote:
>> Il 14/10/2014 06:54, Peter Maydell ha scritto:
>>> Why is this patch only changing this board? What's special
>>> about virt that means we don't want to also make this
>>> change for the other ARM boards? What about all the other
>>> boards for the other architectures?
>>
>> -mem-path is not too useful without KVM (TCG is too slow to
>> notice the difference. PPC and S390 have already been fixed.
>
> MIPS has KVM too now...
Yes.
>>> Incidentally I can't see anything that guards against
>>> calling memory_region_allocate_system_memory() twice,
>>> so I think you would end up with two blocks of RAM
>>> both backed by the same file then. Or have I misread
>>> the code?
>>
>> That would be a bug in the board, it is caught here:
>>
>> if (memory_region_is_mapped(seg)) {
>> char *path =
>> object_get_canonical_path_component(OBJECT(backend));
>> error_report("memory backend %s is used multiple times. Each "
>> "-numa option must use a different memdev value.",
>> path);
>> exit(1);
>> }
>>
>> The error message gives the common user error rather than
>> the less common developer error, but still you catch it.
>
> That's only in the NUMA code path though, isn't it?
> I was looking at the non-numa codepath, which is what
> all the boards I care about are going to be taking :-)
The non-NUMA path will allocate memory from two separate files.
-mem-path takes a path, not a file.
> What's the right thing for a board where the system
> RAM isn't contiguous, by the way?
x86 allocates a big RAM region and uses aliases to split it into
non-contiguous areas.
Paolo
