Re: [PATCH v3] target/arm: handle unaligned PC during tlb probe

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

On 12/4/25 14:35, Alex Bennée wrote:
> PC alignment faults have priority over instruction aborts and we have
> code to deal with this in the translation front-ends. However during
> tb_lookup we can see a potentially faulting probe which doesn't get a
> MemOp set. If the page isn't available this results in
> EC_INSNABORT (0x20) instead of EC_PCALIGNMENT (0x22).
> 
> As there is no easy way to set the appropriate MemOp in the
> instruction fetch probe path lets just detect it in
> arm_cpu_tlb_fill_align() ahead of the main alignment check. We also
> teach arm_deliver_fault to deliver the right syndrome for
> MMU_INST_FETCH alignment issues.
> 
> Fixes:https://gitlab.com/qemu-project/qemu/-/issues/3233
> Tested-by: Jessica Clarke<jrtc27@jrtc27.com>
> Signed-off-by: Alex Bennée<alex.bennee@linaro.org>
> 
> ---
> v2
>    - don't mess with MemOp for alignment check
>    - expand arm_deliver_fault to pick up alignment issues
> v3
>    - update commit message
> ---
>   target/arm/tcg/tlb_helper.c | 21 ++++++++++++++++-----
>   1 file changed, 16 insertions(+), 5 deletions(-)

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

r~