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

[Clément Chigot]

On Mon, Apr 22, 2024 at 11:02 PM Philippe Mathieu-Daudé
<philmd@linaro.org> wrote:
>
> On 22/4/24 19:09, Richard Henderson wrote:
> > 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.
>
> To the best of my knowledge,
> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

Thanks for the patch.

Tested-by: Clément Chigot <chigot@adacore.com>