On Thu, 6 Jan 2022 at 14:26, Alex Bennée <alex.ben...@linaro.org> wrote: > > > Peter Maydell <peter.mayd...@linaro.org> writes: > > > On Wed, 5 Jan 2022 at 21:05, Alex Bennée <alex.ben...@linaro.org> wrote: > >> Can't be added as a subregion to the container... > >> > >> qemu-system-arm: ../../softmmu/memory.c:2538: > >> memory_region_add_subregion_common: Assertion `!subregion->container' > >> failed. > > > > This assert means you tried to add the same MemoryRegion > > as a subregion of more than one parent MR. > > Right - that is probably something we should make (more?) explicitly > clear in the Memory API docs.
The doc comment does document the requirement: * [...] A region * may only be added once as a subregion (unless removed with * memory_region_del_subregion()); use memory_region_init_alias() if you * want a region to be a subregion in multiple locations. One of the deficiencies of C assert() is the lack of an explanatory text message to go along with the raw expression. > > You can either: > > * pass all the CPUs the same container as their "memory" link, > > if they all see the same view of the world > > This should be the case - I don't think the different cores have any > particular different view of the world. The use of the two 4kb banks I > think is purely convention. > > However trying for a single container shared between both cores fails > because armv7m_realize adds it's board_memory to another container: > > memory_region_add_subregion_overlap(&s->container, 0, s->board_memory, > -1); Yeah, that trick only works for the real CPU object, not for passing to SoC or SoC-like objects. > So I guess I just have to repeat the creation of the aliases for each > core. This seems needlessly messy... It's not great, but the MR tree does need each MR to have only one parent. Maybe there's some way to make it a bit less tedious to create the aliases. -- PMM
