Re: Trying to understand QOM object creation and property linking

[Peter Maydell]

On Wed, 5 Jan 2022 at 21:05, Alex Bennée <alex.bennee@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.

You can either:
 * pass all the CPUs the same container as their "memory" link,
   if they all see the same view of the world
 * if they have different views of the world, you need to
   create a container for each CPU to be the "memory" link,
   and to populate that container you need to create N-1 alias MRs
   of the board_memory MR (CPU 0's container can use the original
   board_memory MR; CPU 1, ... use the aliases).

Example of option 1: virt board
Example of option 2: hw/arm/armsse.c (look at what it does with
the s->cpu_container[] and s->container_alias[] arrays)

-- PMM