Hi Michal, > On 13 Mar 2025, at 10:19, Orzel, Michal <michal.or...@amd.com> wrote: > > > > On 12/03/2025 14:52, Luca Fancellu wrote: >> >> >> Rename the setup_pagetables function to setup_mappings in >> order to be implemented also for MPU system that does not >> have page tables. > > mappings is better than pagetables, so: > Reviewed-by: Michal Orzel <michal.or...@amd.com> > > but I'd like to understand what will be implementation of setup_mappings for > MPU. I suppose regions setup such that the following call to early_fdt_map can > succeed and doing this in setup_mm is already too late?
So on the MPU side, mappings are well defined in HW by registers, so we don’t need to allocate pagetables, so setup_mappings in reality will only prepare our logical data structure that tracks the MPU region state (few regions are already written by the asm early code and needs to be tracked). early_fdt_map won’t use this logical view of the MPU (as it’s called early), it will use low level API to access the MPU registers, like the early asm code did, basically to map the DTB. Doing that, we ensure that the current code flow in start_xen can be reused as it. Cheers, Luca
