Re: [PATCH] target/arm: Restrict translation disabled alignment check to VMSA

[Richard Henderson]

On 4/22/24 10:07, Richard Henderson wrote:
> For cpus using PMSA, when the MPU is disabled, the default memory
> type is Normal, Non-cachable.
>
> Fixes: 59754f85ed3 ("target/arm: Do memory type alignment check when translation 
> disabled")
> Reported-by: Clément Chigot <chigot@adacore.com>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>
> Since v9 will likely be tagged tomorrow without this fixed,
> Cc: qemu-stable@nongnu.org
>
> ---
>   target/arm/tcg/hflags.c | 12 ++++++++++--
>   1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/target/arm/tcg/hflags.c b/target/arm/tcg/hflags.c
> index 5da1b0fc1d..66de30b828 100644
> --- a/target/arm/tcg/hflags.c
> +++ b/target/arm/tcg/hflags.c
> @@ -38,8 +38,16 @@ static bool aprofile_require_alignment(CPUARMState *env, int 
> el, uint64_t sctlr)
>       }
>   
>       /*
> -     * If translation is disabled, then the default memory type is
> -     * Device(-nGnRnE) instead of Normal, which requires that alignment
> +     * With PMSA, when the MPU is disabled, all memory types in the
> +     * default map is Normal.
> +     */
> +    if (arm_feature(env, ARM_FEATURE_PMSA)) {
> +        return false;
> +    }
> +
> +    /*
> +     * With VMSA, if translation is disabled, then the default memory type
> +     * is Device(-nGnRnE) instead of Normal, which requires that alignment
>        * be enforced.  Since this affects all ram, it is most efficient
>        * to handle this during translation.
>        */

Oh, I meant to add: since the armv7 manual has both VMSA and PMSA sections, and the 
language about default Device type and alignment traps, is in the VMSA section.
This will at least fix our two r-profile cpus.

r~