Re: [Qemu-devel] [PATCH 4/4] target/arm: Enable TBI for user-only

[Peter Maydell <peter.maydell@linaro.org>]

On Thu, 10 Jan 2019 at 12:50, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> This has been enabled in the linux kernel since v3.11
> (commit d50240a5f6cea, 2013-09-03,
> "arm64: mm: permit use of tagged pointers at EL0").
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  target/arm/cpu.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/target/arm/cpu.c b/target/arm/cpu.c
> index 14bc24a35a..5eff6995ee 100644
> --- a/target/arm/cpu.c
> +++ b/target/arm/cpu.c
> @@ -174,6 +174,12 @@ static void arm_cpu_reset(CPUState *s)
>          env->vfp.zcr_el[1] = cpu->sve_max_vq - 1;
>          env->vfp.zcr_el[2] = env->vfp.zcr_el[1];
>          env->vfp.zcr_el[3] = env->vfp.zcr_el[1];
> +        /*
> +         * Enable TBI0 and TBI1.  While the real kernel only enables TBI0,
> +         * turning on both here will produce smaller code and otherwise
> +         * make no difference to the user-level emulation.
> +         */
> +        env->cp15.tcr_el[1].raw_tcr = (3ULL << 37);
>  #else
>          /* Reset into the highest available EL */
>          if (arm_feature(env, ARM_FEATURE_EL3)) {
> --
> 2.17.2

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

thanks
-- PMM