Re: [Qemu-devel] [PATCH 08/20] memory: store MemoryRegionSection pointers in phys_map

[Peter Maydell]

On 8 March 2012 11:11, Avi Kivity <address@hidden> wrote:
> On 03/08/2012 12:09 PM, Peter Maydell wrote:
>> Is that exec.c comment now out of date?
>
> For subpage, I think so.  It's still broken for page aligned regions
> that have low bits set in their offset:
>
>  memory_region_init_io(foo, ..., 4097)
>  memory_region_add_subregion(sysmem, 4095, foo);
>
> the 4095-4096 region will work, but the 4096-8191 region will not.  I'll
> address it later when I'll regress the memory core in other ways.

Right, so as long as your region is less than a page in size it's
OK. That should be enough for me to do a cleanup I've been wanting
to do for ages: the v7M NVIC should really be modelled as a region
from 0xE000E100 .. 0xE000ECFF overlaying the general "system registers"
region from 0xE000E000 .. 0xE000EFFF, but at the moment there's
a nasty hack in the interrupt controller read/write routines that
says "if offset in this range then call a different function in
another device"...

-- PMM