Re: [PATCH v2] xen/arm: Do not route NS phys timer IRQ to Xen

[Julien Grall <julien@xxxxxxx>]

Hi Michal,

On 28/10/2022 14:49, Michal Orzel wrote:
> At the moment, we route NS phys timer IRQ to Xen even though it does not
> make use of this timer. Xen uses hypervisor timer for itself and the
> physical timer is fully emulated, hence there is nothing that can trigger
> such IRQ. This means that requesting/releasing IRQ ends up as a deadcode
> as it has no impact on the functional behavior, whereas the code within
> a handler ends up being unreachable. This is a left over from the early
> days when the CNTHP IRQ was buggy on the HW model used for testing and we
> had to use the CNTP instead.
>
> Remove the calls to {request/release}_irq for this timer as well as the
> code within the handler. Since timer_interrupt handler is now only used
> by the CNTHP, refactor it as follows:
>   - rename it to htimer_interrupt to reflect its purpose,
>   - remove the IRQ affiliation test,
>   - invert the condition to avoid indented code and use unlikely,
>   - improve readability by adding new lines \btw code and comments.
>
> Keep the calls to zero the CNTP_CTL_EL0 register for sanity and also
> remove the corresponding perf counter definition.
>
> Signed-off-by: Michal Orzel <michal.orzel@xxxxxxx>
Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>

Cheers,

--
Julien Grall