Re: [PATCH v2 3/8] evtchn: rename and adjust guest_enabled_event()

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Tue, Oct 20, 2020 at 04:09:16PM +0200, Jan Beulich wrote:
> The function isn't about an "event" in general, but about a vIRQ. The
> function also failed to honor global vIRQ-s, instead assuming the caller
> would pass vCPU 0 in such a case.
> 
> While at it also adjust the
> - types the function uses,
> - single user to make use of domain_vcpu().
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

> ---
> v2: New.
> 
> --- a/xen/arch/x86/cpu/mcheck/vmce.h
> +++ b/xen/arch/x86/cpu/mcheck/vmce.h
> @@ -5,9 +5,9 @@
>  
>  int vmce_init(struct cpuinfo_x86 *c);
>  
> -#define dom0_vmce_enabled() (hardware_domain && hardware_domain->max_vcpus \
> -        && hardware_domain->vcpu[0] \
> -        && guest_enabled_event(hardware_domain->vcpu[0], VIRQ_MCA))
> +#define dom0_vmce_enabled() \
> +    (hardware_domain && \
> +     evtchn_virq_enabled(domain_vcpu(hardware_domain, 0), VIRQ_MCA))
>  
>  int unmmap_broken_page(struct domain *d, mfn_t mfn, unsigned long gfn);
>  
> --- a/xen/common/event_channel.c
> +++ b/xen/common/event_channel.c
> @@ -778,9 +778,15 @@ out:
>      return ret;
>  }
>  
> -int guest_enabled_event(struct vcpu *v, uint32_t virq)
> +bool evtchn_virq_enabled(const struct vcpu *v, unsigned int virq)
>  {
> -    return ((v != NULL) && (v->virq_to_evtchn[virq] != 0));
> +    if ( !v )

Not sure it's worth adding a check that virq < NR_VIRQS here just to
be on the safe side...

> +        return false;
> +
> +    if ( virq_is_global(virq) && v->vcpu_id )

...as virq_is_global has an ASSERT to that extend (but that would be a
nop on release builds).

Thanks, Roger.