Re: [PATCH] ARM/vgic: Use for_each_set_bit() in vgic_sync_from_lrs()

[Julien Grall <julien@xxxxxxx>]

Hi,

On 05/03/2026 23:28, Andrew Cooper wrote:
> lr_mask doesn't have bits set beyond the hardware limit, with the upper bits
> remaining zero.  Therefore, for_each_set_bit() is a better option.
>
> For ARM64, bloat-o-meter reports:
>
>    Function                                     old     new   delta
>    vgic_sync_from_lrs                           208     168     -40
>
> but this doesn't highlight that it also removes a call to find_next_bit() from
> each loop iteration.
>
> No functional change.
>
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Acked-by: Julien Grall <julien@xxxxxxx>

> ---
> CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> CC: Julien Grall <julien@xxxxxxx>
> CC: Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
> CC: Bertrand Marquis <bertrand.marquis@xxxxxxx>
> CC: Michal Orzel <michal.orzel@xxxxxxx>
> CC: Jan Beulich <JBeulich@xxxxxxxx>
> CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> CC: Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>
>
> RFC.  This form also doesn't suffer an OoB read when lr_mask changes type.
And potentially unaligned as well. On Arm 32, this would result to a 
crash because for forbid unaligned access.
Cheers,

--
Julien Grall