On Mon, 2022-12-05 at 15:20 +0100, Thomas Huth wrote:
> The PSW key mask is a 16 bit field, and the psw_key variable is
> in the range from 0 to 15, so it does not make sense to use
> "0x80 >> psw_key" for testing the bits here. We should use 0x8000
> instead.
>
> Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
> ---
> Found by code inspection (Linux likely does not use these PSW key masks
> yet, otherwise we might have noticed earlier)
>
> target/s390x/tcg/mem_helper.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/target/s390x/tcg/mem_helper.c b/target/s390x/tcg/mem_helper.c
> index 9542fad59b..cb82cd1c1d 100644
> --- a/target/s390x/tcg/mem_helper.c
> +++ b/target/s390x/tcg/mem_helper.c
> @@ -51,7 +51,7 @@ static inline bool psw_key_valid(CPUS390XState *env, uint8_t psw_key)
>
> if (env->psw.mask & PSW_MASK_PSTATE) {
> /* PSW key has range 0..15, it is valid if the bit is 1 in the PKM */
> - return pkm & (0x80 >> psw_key);
> + return pkm & (0x8000 >> psw_key);
> }
> return true;
> }