linux-user/aarch64: Introduce sve_vq

Add an interface function to extract the digested vector length
rather than the raw zcr_el[1] value.  This fixes an incorrect
return from do_prctl_set_vl where we didn't take into account
the set of vector lengths supported by the cpu.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220607203306.657998-3-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
3 files changed