Re: [PATCH v4 34/45] linux-user/aarch64: Reset PSTATE.SM on syscalls

[Peter Maydell]

On Tue, 28 Jun 2022 at 06:26, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  linux-user/aarch64/cpu_loop.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/linux-user/aarch64/cpu_loop.c b/linux-user/aarch64/cpu_loop.c
> index 3b273f6299..4af6996d57 100644
> --- a/linux-user/aarch64/cpu_loop.c
> +++ b/linux-user/aarch64/cpu_loop.c
> @@ -89,6 +89,15 @@ void cpu_loop(CPUARMState *env)
>
>          switch (trapnr) {
>          case EXCP_SWI:
> +            /*
> +             * On syscall, PSTATE.ZA is preserved, along with the ZA matrix.
> +             * PSTATE.SM is cleared, per SMSTOP, which does ResetSVEState.
> +             */
> +            if (FIELD_EX64(env->svcr, SVCR, SM)) {
> +                env->svcr = FIELD_DP64(env->svcr, SVCR, SM, 0);
> +                arm_rebuild_hflags(env);
> +                arm_reset_sve_state(env);
> +            }
>              ret = do_syscall(env,
>                               env->xregs[8],
>                               env->xregs[0],
> --

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

thanks
-- PMM