Re: [Xen-devel] [PATCH v2 2/5] arm: implement vcpu_mark_events_pending

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Thu, 2012-02-23 at 18:21 +0000, Stefano Stabellini wrote:
> Implement vcpu_mark_events_pending using the vgic to inject INT 63, that
> we reserve for Xen usage.

Does this require a trap when the guest acks or EOIs this interrupt?
What about maintenance interrupts arising from injecting this?

Might we want to instead inject this interrupt as an SGI, so that it
appears as a per-VCPU interrupt?

> In the future the interrupt used for event injection might be dynamic
> and could be written into the device tree.

I think this is required, isn't it? At least for the privileged domain
which also sees physical interrupts, unless we want to get into playing
tricks with non 1:1 interrupts.

> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> ---
>  xen/arch/arm/domain.c |   11 +++++++++++
>  xen/arch/arm/dummy.S  |    1 -
>  xen/arch/arm/gic.h    |    3 +++
>  3 files changed, 14 insertions(+), 1 deletions(-)
> 
> diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
> index 0ee96b9..4752aaa 100644
> --- a/xen/arch/arm/domain.c
> +++ b/xen/arch/arm/domain.c
> @@ -272,6 +272,17 @@ void arch_dump_vcpu_info(struct vcpu *v)
>  {
>  }
>  
> +void vcpu_mark_events_pending(struct vcpu *v)
> +{
> +    int already_pending = test_and_set_bit(
> +        0, (unsigned long *)&vcpu_info(v, evtchn_upcall_pending));
> +
> +    if ( already_pending )
> +        return;
> +
> +    vgic_vcpu_inject_irq(v, VGIC_IRQ_EVTCHN_CALLBACK, 1);
> +}
> +
>  /*
>   * Local variables:
>   * mode: C
> diff --git a/xen/arch/arm/dummy.S b/xen/arch/arm/dummy.S
> index 3f2cc4b..93f6f53 100644
> --- a/xen/arch/arm/dummy.S
> +++ b/xen/arch/arm/dummy.S
> @@ -31,7 +31,6 @@ DUMMY(arch_vcpu_reset);
>  DUMMY(free_vcpu_guest_context);
>  DUMMY(sync_vcpu_execstate);
>  NOP(update_vcpu_system_time);
> -DUMMY(vcpu_mark_events_pending);
>  DUMMY(vcpu_show_execution_state);
>  
>  /* Page Reference & Type Maintenance */
> diff --git a/xen/arch/arm/gic.h b/xen/arch/arm/gic.h
> index 81c388d..36fdea1 100644
> --- a/xen/arch/arm/gic.h
> +++ b/xen/arch/arm/gic.h
> @@ -121,6 +121,9 @@
>  #define GICH_LR_CPUID_SHIFT     9
>  #define GICH_VTR_NRLRGS         0x3f
>  
> +/* XXX: write this into the DT */
> +#define VGIC_IRQ_EVTCHN_CALLBACK 63
> +
>  extern int domain_vgic_init(struct domain *d);
>  extern int vcpu_vgic_init(struct vcpu *v);
>  extern void vgic_vcpu_inject_irq(struct vcpu *v, unsigned int irq,int 
> virtual);



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel