Re: [PATCH 4/4] target/arm: Ignore SMCR_EL2.LEN and SVCR_EL2.LEN if EL2 is not enabled

[Philippe Mathieu-Daudé]

On 22/7/24 19:29, Peter Maydell wrote:
> When determining the current vector length, the SMCR_EL2.LEN and
> SVCR_EL2.LEN settings should only be considered if EL2 is enabled
> (compare the pseudocode CurrentSVL and CurrentNSVL which call
> EL2Enabled()).
>
> We were checking against ARM_FEATURE_EL2 rather than calling
> arm_is_el2_enabled(), which meant that we would look at
> SMCR_EL2/SVCR_EL2 when in Secure EL1 or Secure EL0 even if Secure EL2
> was not enabled.

Just curious, how did you notice?

> Use the correct check in sve_vqm1_for_el_sm().
>
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>   target/arm/helper.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/target/arm/helper.c b/target/arm/helper.c
> index ce319572354..8fb4b474e83 100644
> --- a/target/arm/helper.c
> +++ b/target/arm/helper.c
> @@ -7232,7 +7232,7 @@ uint32_t sve_vqm1_for_el_sm(CPUARMState *env, int el, 
> bool sm)
>       if (el <= 1 && !el_is_in_host(env, el)) {
>           len = MIN(len, 0xf & (uint32_t)cr[1]);
>       }
> -    if (el <= 2 && arm_feature(env, ARM_FEATURE_EL2)) {
> +    if (el <= 2 && arm_is_el2_enabled(env)) {
>           len = MIN(len, 0xf & (uint32_t)cr[2]);
>       }
>       if (arm_feature(env, ARM_FEATURE_EL3)) {