Re: [PATCH] x86/hap: Inline "flush_vcpu" in "flush_tlb"

["Roger Pau Monné" <roger.pau@citrix.com>]

On Mon, Sep 29, 2025 at 12:36:30PM +0000, Teddy Astie wrote:
> flush_vcpu static function here is only used in one place which is just below
> where it is defined. Inline the function to reduce the noise and clarify
> what we are doing.

Did you check that the compiler doesn't inline it already?

It seems like an obvious optimization for the compiler to do.

> No functional change.
> 
> Signed-off-by: Teddy Astie <teddy.astie@vates.tech>
> ---
>  xen/arch/x86/mm/hap/hap.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
> 
> diff --git a/xen/arch/x86/mm/hap/hap.c b/xen/arch/x86/mm/hap/hap.c
> index 2f69ff9c7b..407c80afab 100644
> --- a/xen/arch/x86/mm/hap/hap.c
> +++ b/xen/arch/x86/mm/hap/hap.c
> @@ -721,11 +721,6 @@ static pagetable_t cf_check hap_update_cr3(struct vcpu *v, bool noflush)
>      return pagetable_null();
>  }
>  
> -static bool flush_vcpu(const struct vcpu *v, const unsigned long *vcpu_bitmap)
> -{
> -    return !vcpu_bitmap || test_bit(v->vcpu_id, vcpu_bitmap);

The same construct is used in shadow code also, maybe it would be
helpful to place the flush_vcpu() helper in a common header as static
inline?

OTOH we don't care much for shadow, so it might be simpler to leave
shadow as-is and do the change just for HAP, but would be good to
mention in the commit message why shadow is not adjusted in the same
way.

Thanks, Roger.