Re: [PATCH 1/2] target/xtensa: wrap MMU and MPU state into structures

[Peter Maydell]

On Fri, 19 Jan 2024 at 20:47, Max Filippov <jcmvbkbc@gmail.com> wrote:
>
> Make separation of alternative xtensa memory management options state
> explicit.
>
> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
> ---
>  target/xtensa/cpu.h        | 18 +++++++++++++----
>  target/xtensa/mmu_helper.c | 40 +++++++++++++++++++-------------------
>  2 files changed, 34 insertions(+), 24 deletions(-)
>
> diff --git a/target/xtensa/cpu.h b/target/xtensa/cpu.h
> index 8a423706d8c0..497325466397 100644
> --- a/target/xtensa/cpu.h
> +++ b/target/xtensa/cpu.h
> @@ -326,11 +326,21 @@ typedef struct xtensa_tlb {
>      unsigned nrefillentries;
>  } xtensa_tlb;
>
> +typedef struct XtensaMMU {
> +    xtensa_tlb_entry itlb[7][MAX_TLB_WAY_SIZE];
> +    xtensa_tlb_entry dtlb[10][MAX_TLB_WAY_SIZE];
> +    unsigned autorefill_idx;
> +} XtensaMMU;
> +
>  typedef struct xtensa_mpu_entry {
>      uint32_t vaddr;
>      uint32_t attr;
>  } xtensa_mpu_entry;
>
> +typedef struct XtensaMPU {
> +    xtensa_mpu_entry fg[MAX_MPU_FOREGROUND_SEGMENTS];
> +} XtensaMPU;
> +
>  typedef struct XtensaGdbReg {
>      int targno;
>      unsigned flags;
> @@ -526,10 +536,10 @@ struct CPUArchState {
>      uint32_t exclusive_val;
>
>  #ifndef CONFIG_USER_ONLY
> -    xtensa_tlb_entry itlb[7][MAX_TLB_WAY_SIZE];
> -    xtensa_tlb_entry dtlb[10][MAX_TLB_WAY_SIZE];
> -    xtensa_mpu_entry mpu_fg[MAX_MPU_FOREGROUND_SEGMENTS];
> -    unsigned autorefill_idx;
> +    union {
> +        XtensaMMU mmu;
> +        XtensaMPU mpu;
> +    };

Is it really worth having this be a union ? I suspect it will
make adding migration/savevm support later more awkward.

>      bool runstall;
>      AddressSpace *address_space_er;
>      MemoryRegion *system_er;

Otherwise
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM