Re: [PATCH for-8.2 0/3] arm: Use correct number of MPU regions on mps2-tz boards

[Peter Maydell]

On Mon, 24 Jul 2023 at 18:43, Peter Maydell <peter.maydell@linaro.org> wrote:
>
> This patchseries resolves issue
> https://gitlab.com/qemu-project/qemu/-/issues/1772
> which is a report that we don't implement the correct number of MPU
> regions on our MPS2/MPS3 boards.  Ideally guest software ought not to
> care since (a) it can find out the number of regions by looking at
> the MPU_TYPE register and (b) if it wanted 8 MPU regions it can just
> ignore the 8 extra ones.  However, Zephyr at least seems both to
> hardcode this and to care.
>
> Patch 1 cleans up a bug in target/arm code that meant that we
> were accidentally not exposing the pmsav7-dregion on v8M CPUs.
>
> Patches 2 and 3 then define properties on the armv7m object
> and the ARMSSE SoC object, and have the mps2-tz.c board code
> set the properties appropriately to match the config as
> described for those FPGA images.
>
> I have not looked at whether we also get this wrong for the
> older (M3, M4, M7) boards in hw/arm/mps2.c.

I checked up on this, and for these cores the hardware
is not configurable -- they always have 8 MPU regions,
which is the way our models of them are set up. So these
boards (mps2-an385, -an386, -an500, -an511) are fine.

thanks
-- PMM