Re: [PATCH 00/23] Fix NB_MMU_MODES to 16

[Philippe Mathieu-Daudé]

On 6/3/23 18:52, Anton Johansson wrote:
> This patchset fixes NB_MMU_MODES to 16 for all targets, meaning the
> macro is no longer target-specific.  16 mmu modes is large enough to
> cover all currently supported targets (12 arm, 10 ppc, ...), and is the
> maxiumum supported by the softmmu tlb api.
>
> As mentioned by Richard in response to our RFC, softmmu tlbs are
> dynamically resized and so the overhead of an unused mmu index is fairly
> low.
>
> The grand goal is to allow for heterogeneous QEMU binaries
> consisting of multiple frontends.
>
> RFC: https://lists.nongnu.org/archive/html/qemu-devel/2022-12/msg04518.html
>
> Anton Johansson (23):
>    include/exec: Set default `NB_MMU_MODES` to 16
>    target/alpha: Remove `NB_MMU_MODES` define
>    target/arm: Remove `NB_MMU_MODES` define
>    target/avr: Remove `NB_MMU_MODES` define
>    target/cris: Remove `NB_MMU_MODES` define
>    target/hexagon: Remove `NB_MMU_MODES` define
>    target/hppa: Remove `NB_MMU_MODES` define
>    target/i386: Remove `NB_MMU_MODES` define
>    target/loongarch: Remove `NB_MMU_MODES` define
>    target/m68k: Remove `NB_MMU_MODES` define
>    target/microblaze: Remove `NB_MMU_MODES` define
>    target/mips: Remove `NB_MMU_MODES` define
>    target/nios2: Remove `NB_MMU_MODES` define
>    target/openrisc: Remove `NB_MMU_MODES` define
>    target/ppc: Remove `NB_MMU_MODES` define
>    target/riscv: Remove `NB_MMU_MODES` define
>    target/rx: Remove `NB_MMU_MODES` define
>    target/s390x: Remove `NB_MMU_MODES` define
>    target/sh4: Remove `NB_MMU_MODES` define
>    target/sparc: Remove `NB_MMU_MODES` define
>    target/tricore: Remove `NB_MMU_MODES` define
>    target/xtensa: Remove `NB_MMU_MODES` define
>    include/exec: Remove guards around `NB_MMU_MODES`

As 24/23 we can remove the assertion in qemu_plugin_get_hwaddr().

Then NB_MMU_MODES is only used by CPUTLB in "exec/cpu-defs.h" and
in accel/tcg/cputlb.c.