Re: [PATCH 08/22] include/exec/memattrs: Add two bits of space to MemTxAttrs

[Peter Maydell]

On Tue, 24 Jan 2023 at 00:01, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> We will need 2 bits to represent ARMSecurityState.
>
> Do not attempt to replace or widen secure, even though it
> logically overlaps the new field -- there are uses within
> e.g. hw/block/pflash_cfi01.c, which don't know anything
> specific about ARM.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  include/exec/memattrs.h | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/include/exec/memattrs.h b/include/exec/memattrs.h
> index 9fb98bc1ef..d04170aa27 100644
> --- a/include/exec/memattrs.h
> +++ b/include/exec/memattrs.h
> @@ -29,10 +29,17 @@ typedef struct MemTxAttrs {
>       * "didn't specify" if necessary.
>       */
>      unsigned int unspecified:1;
> -    /* ARM/AMBA: TrustZone Secure access
> +    /*
> +     * ARM/AMBA: TrustZone Secure access
>       * x86: System Management Mode access
>       */
>      unsigned int secure:1;
> +    /*
> +     * ARM: ArmSecuritySpace.  This partially overlaps secure, but it is
> +     * easier to have both fields to assist code that does not understand
> +     * ARMv9 RME, or no specific knowledge of ARM at all (e.g. pflash).
> +     */
> +    unsigned int space:2;
>      /* Memory access is usermode (unprivileged) */
>      unsigned int user:1;

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

I guess we aren't so tight on bits in this struct as to
warrant keeping the extra RME info in a single bit (which
should in theory be possible).

thanks
-- PMM