Re: [PATCH] target/arm: Use correct entrypoint for SVC taken from Hyp to Hyp

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

On 1/18/22 00:19, Peter Maydell wrote:
> The exception caused by an SVC instruction may be taken to AArch32
> Hyp mode for two reasons:
>   * HCR.TGE indicates that exceptions from EL0 should trap to EL2
>   * we were already in Hyp mode
> 
> The entrypoint in the vector table to be used differs in these two
> cases: for an exception routed to Hyp mode from EL0, we enter at the
> common 0x14 "hyp trap" entrypoint.  For SVC from Hyp mode to Hyp
> mode, we enter at the 0x08 (svc/hvc trap) entrypoint.
> In the v8A Arm ARM pseudocode this is done in AArch32.TakeSVCException.
> 
> QEMU incorrectly routed both of these exceptions to the 0x14
> entrypoint.  Correct the entrypoint for SVC from Hyp to Hyp by making
> use of the existing logic which handles "normal entrypoint for
> Hyp-to-Hyp, otherwise 0x14" for traps like UNDEF and data/prefetch
> aborts (reproduced here since it's outside the visible context
> in the diff for this commit):
> 
>      if (arm_current_el(env) != 2 && addr < 0x14) {
>          addr = 0x14;
>      }
> 
> Signed-off-by: Peter Maydell<peter.maydell@linaro.org>
> ---
>   target/arm/helper.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)

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

r~