On 03/08/2012 12:09 PM, Peter Maydell wrote: > On 8 March 2012 09:50, Avi Kivity <a...@redhat.com> wrote: > > On 03/07/2012 09:32 PM, Peter Maydell wrote: > >> Are we running into the "mapping devices at non-page-offsets isn't > >> supported" issue here? > > > > It wasn't supported? > > Well, you used to run into the issue noted in the comment above > exec.c:register_subpage(): > The address used when calling the IO function is > the offset from the start of the region, plus region_offset. Both > start_addr and region_offset are rounded down to a page boundary > before calculating this offset. This should not be a problem unless > the low bits of start_addr and region_offset differ. > > and for non-page-aligned IO regions we were getting bitten by > this rounding, which is why the offset passed into the read/write > function was strange. > > Is that exec.c comment now out of date?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. > (You might recall we had a conversation about this a little while > back: http://patchwork.ozlabs.org/patch/129267/ ) I had a full memory wipe done during my vacation, so no. -- error compiling committee.c: too many arguments to function
