Re: [Qemu-devel] [PATCH v2] target/arm: Implement NSACR gating of floating point

[Richard Henderson <richard.henderson@linaro.org>]

On 6/7/19 8:06 AM, Peter Maydell wrote:
> The NSACR register allows secure code to configure the FPU
> to be inaccessible to non-secure code. If the NSACR.CP10
> bit is set then:
>  * NS accesses to the FPU trap as UNDEF (ie to NS EL1 or EL2)
>  * CPACR.{CP10,CP11} behave as if RAZ/WI
>  * HCPTR.{TCP11,TCP10} behave as if RAO/WI
> 
> Note that we do not implement the NSACR.NSASEDIS bit which
> gates only access to Advanced SIMD, in the same way that
> we don't implement the equivalent CPACR.ASEDIS and HCPTR.TASE.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> Changes v1->v2:
>  * fixed bug in cptr_el2_read() that meant we were forcing
>    HCPTR.{TCP11,TCP10} to 0 when they should be 1
> ---
>  target/arm/helper.c | 75 +++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 73 insertions(+), 2 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~