Re: [Qemu-devel] [PATCH 04/38] tests/libqos/pci-pc: Fix qpci_pc_iomap() to map BARs aligned

[Markus Armbruster]

Marc-André Lureau <address@hidden> writes:

> On Mon, Feb 29, 2016 at 7:40 PM, Markus Armbruster <address@hidden> wrote:
>> qpci_pc_iomap() maps BARs one after the other, without padding.  This
>> is wrong.  PCI Local Bus Specification Revision 3.0, 6.2.5.1. Address
>> Maps: "all address spaces used are a power of two in size and are
>> naturally aligned".  That's because the size of a BAR is given by the
>> number of address bits the device decodes, and the BAR needs to be
>> mapped at a multiple of that size to ensure the address decoding
>> works.
>>
>> Fix qpci_pc_iomap() accordingly.  This takes care of a FIXME in
>> ivshmem-test.
>>
>> Signed-off-by: Markus Armbruster <address@hidden>
>
> Reviewed-by: Marc-André Lureau <address@hidden>
>
> Neat, thanks for fixing my fixme ;)

You're welcome :)

Of course, I found it the hard way regardless.  I experimented with new
tests, and suddenly *nothing* worked anymore.  WTF?!?  After "some"
debugging, I notced a BAR mapped at a funny address...  what happens if
I align it properly?  Everything works, that's what happens.  And then I
remembered your FIXME.

Thanks!