Re: [Xen-devel] [PATCH v2 01/45] ARM: VGIC: rename gic_event_needs_delivery()

[Julien Grall <julien.grall@xxxxxxx>]

Hi Andre,

On 15/03/18 20:30, Andre Przywara wrote:
> gic_event_needs_delivery() is not named very intuitively, especially
> the gic_ prefix is somewhat misleading.
> Rename it to vgic_vcpu_pending_irq(), which makes it clear that this
> relates to the virtual GIC and is about interrupts.
> Also add a VCPU parameter, which makes the code more flexible in the
> future. The current VGIC expect this to be the current VCPU, so add
> an assert to spot any regressions.
>
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxxxxx>
Reviewed-by: Julien Grall <julien.grall@xxxxxxx>

Cheers,

> ---
> Changelog v1 .. v2:
> - rename to vgic_vcpu_pending_irq()
> - add VCPU parameter
>
>   xen/arch/arm/gic-vgic.c     | 16 ++++++++++++++--
>   xen/include/asm-arm/event.h |  2 +-
>   xen/include/asm-arm/gic.h   |  2 +-
>   3 files changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/xen/arch/arm/gic-vgic.c b/xen/arch/arm/gic-vgic.c
> index ecb07ceb40..61f093db50 100644
> --- a/xen/arch/arm/gic-vgic.c
> +++ b/xen/arch/arm/gic-vgic.c
> @@ -339,9 +339,18 @@ void gic_clear_pending_irqs(struct vcpu *v)
>           gic_remove_from_lr_pending(v, p);
>   }
>   
> -int gic_events_need_delivery(void)
> +/**
> + * vgic_vcpu_pending_irq() - determine if interrupts need to be injected
> + * @vcpu: The vCPU on which to check for interrupts.
> + *
> + * Checks whether there is an interrupt on the given VCPU which needs
> + * handling in the guest. This requires at least one IRQ to be pending
> + * and enabled.
> + *
> + * Returns: 1 if the guest should run to handle interrupts, 0 otherwise.
> + */
> +int vgic_vcpu_pending_irq(struct vcpu *v)
>   {
> -    struct vcpu *v = current;
>       struct pending_irq *p;
>       unsigned long flags;
>       const unsigned long apr = gic_hw_ops->read_apr(0);
> @@ -349,6 +358,9 @@ int gic_events_need_delivery(void)
>       int active_priority;
>       int rc = 0;
>   
> +    /* We rely on reading the VMCR, which is only accessible locally. */
> +    ASSERT(v == current);
> +
>       mask_priority = gic_hw_ops->read_vmcr_priority();
>       active_priority = find_next_bit(&apr, 32, 0);
>   
> diff --git a/xen/include/asm-arm/event.h b/xen/include/asm-arm/event.h
> index e8c2a6cb44..c7a415ef57 100644
> --- a/xen/include/asm-arm/event.h
> +++ b/xen/include/asm-arm/event.h
> @@ -24,7 +24,7 @@ static inline int local_events_need_delivery_nomask(void)
>        * interrupts disabled so this shouldn't be a problem in the general
>        * case.
>        */
> -    if ( gic_events_need_delivery() )
> +    if ( vgic_vcpu_pending_irq(current) )
>           return 1;
>   
>       if ( !vcpu_info(current, evtchn_upcall_pending) )
> diff --git a/xen/include/asm-arm/gic.h b/xen/include/asm-arm/gic.h
> index d568957dd1..49cb94f792 100644
> --- a/xen/include/asm-arm/gic.h
> +++ b/xen/include/asm-arm/gic.h
> @@ -238,7 +238,7 @@ int gic_remove_irq_from_guest(struct domain *d, unsigned 
> int virq,
>   
>   extern void vgic_sync_to_lrs(void);
>   extern void gic_clear_pending_irqs(struct vcpu *v);
> -extern int gic_events_need_delivery(void);
> +extern int vgic_vcpu_pending_irq(struct vcpu *v);
>   
>   extern void init_maintenance_interrupt(void);
>   extern void gic_raise_guest_irq(struct vcpu *v, unsigned int irq,
--
Julien Grall

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