> On Sep 9, 2015, at 10:02 AM, Ard Biesheuvel <[email protected]> wrote: > >> >> >> The 1:1 mapping only goes to 4 GB, so anything beyond that is never >> mapped anyway. >> >> >> This is the state when you hand off to the OS, but it is possible as part of >> the boot process to have a driver do some alternate mapping. This was done >> on x86 servers for a software based memory test for example. >> > > OK, thanks Andrew. I have no idea if the 32-bit ARM MMU code would > deal with that at all (you would probably know better than I), but I > was just trying to get my 32-bit QEMU working with > 3 GB of memory. > > So in patch #2, I needed to split the memory into two regions to get > the DXE core to handle it correctly, one below 4 GB and one above 4 > GB. Is that expected?
There could be some assumptions, like the memory > 4GB is passed up to the DXE Core untested, or added later. This seems like an area that could be documented better in the PI specification. Maybe the MdeModulePkg maintainer would have some insight into the assumptions in the DXE Core implementation? Thanks, Andrew Fish _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
