RE: [Xen-devel] [PATCH] Dont' round-robin the callback interrupt

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

Oops. Sorry, don't apply that... missing break statement. Will resend shortly.

  Paul

> -----Original Message-----
> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-
> bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Paul Durrant
> Sent: 12 July 2010 16:42
> To: xen-devel@xxxxxxxxxxxxxxxxxxx
> Cc: Tim Deegan
> Subject: [Xen-devel] [PATCH] Dont' round-robin the callback
> interrupt
> 
> # HG changeset patch
> # User Paul Durrant <paul.durrant@xxxxxxxxxx>
> # Date 1278948846 -3600
> # Node ID 2dbd30d4027eeafc41fa46638679eb7e3e1bc951
> # Parent  f12837d7a50e3e5f843bd1a7113bb329661c7dd0
> Dont' round-robin the callback interrupt.
> 
> Arrange that the event channel callback interrupt always goes to the
> lowest vcpu with a matching local apic. This should, in most cases,
> be VCPU0 (to which all event channels are bound for HVM guests) but
> this cannot be guaranteed.
> 
> Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
> CC: Tim Deegan <tim.deegan@xxxxxxxxxx>
> 
> diff -r f12837d7a50e -r 2dbd30d4027e xen/arch/x86/hvm/vioapic.c
> --- a/xen/arch/x86/hvm/vioapic.c      Mon Jul 12 10:48:34 2010 +0100
> +++ b/xen/arch/x86/hvm/vioapic.c      Mon Jul 12 16:34:06 2010 +0100
> @@ -276,6 +276,29 @@
>      return pt_active(&pit->pt0);
>  }
> 
> +static int is_callback_via(struct domain *d, int irq)
> +{
> +    struct hvm_irq *hvm_irq = &d->arch.hvm_domain.irq;
> +
> +    switch ( hvm_irq->callback_via_type )
> +    {
> +    case HVMIRQ_callback_gsi: {
> +        unsigned int gsi = hvm_irq->callback_via.gsi;
> +
> +        return irq == gsi;
> +    }
> +    case HVMIRQ_callback_pci_intx: {
> +        unsigned int pdev  = hvm_irq->callback_via.pci.dev;
> +        unsigned int pintx = hvm_irq->callback_via.pci.intx;
> +
> +        return irq == hvm_pci_intx_gsi(pdev, pintx);
> +    }
> +    case HVMIRQ_callback_vector:
> +    default:
> +        return 0;
> +    }
> +}
> +
>  static void vioapic_deliver(struct hvm_hw_vioapic *vioapic, int
> irq)
>  {
>      uint16_t dest = vioapic->redirtbl[irq].fields.dest_id;
> @@ -307,7 +330,11 @@
>          }
>          else
>  #endif
> +        if ( is_callback_via(d, irq) )
> +            target = vlapic_lowest_vcpu(d, NULL, 0, dest,
> dest_mode);
> +        else
>              target = vlapic_lowest_prio(d, NULL, 0, dest,
> dest_mode);
> +
>          if ( target != NULL )
>          {
>              ioapic_inj_irq(vioapic, target, vector, trig_mode,
> delivery_mode);
> diff -r f12837d7a50e -r 2dbd30d4027e xen/arch/x86/hvm/vlapic.c
> --- a/xen/arch/x86/hvm/vlapic.c       Mon Jul 12 10:48:34 2010 +0100
> +++ b/xen/arch/x86/hvm/vlapic.c       Mon Jul 12 16:34:06 2010 +0100
> @@ -354,6 +354,27 @@
>      if ( target != NULL )
>          d->arch.hvm_domain.irq.round_robin_prev_vcpu =
>              vlapic_vcpu(target)->vcpu_id;
> +
> +    return target;
> +}
> +
> +struct vlapic *vlapic_lowest_vcpu(
> +    struct domain *d, struct vlapic *source,
> +    int short_hand, uint8_t dest, uint8_t dest_mode)
> +{
> +    struct vlapic *vlapic, *target = NULL;
> +    struct vcpu *v;
> +
> +    if ( unlikely(!d->vcpu) )
> +        return NULL;
> +
> +    for ( v = d->vcpu[0]; v; v = v->next_in_list ) {
> +        vlapic = vcpu_vlapic(v);
> +        if ( vlapic_match_dest(vlapic, source, short_hand, dest,
> dest_mode) &&
> +             vlapic_enabled(vlapic) ) {
> +            target = vlapic;
> +        }
> +    }
> 
>      return target;
>  }
> diff -r f12837d7a50e -r 2dbd30d4027e xen/include/asm-
> x86/hvm/vlapic.h
> --- a/xen/include/asm-x86/hvm/vlapic.h        Mon Jul 12 10:48:34 2010
> +0100
> +++ b/xen/include/asm-x86/hvm/vlapic.h        Mon Jul 12 16:34:06 2010
> +0100
> @@ -100,6 +100,10 @@
>      struct domain *d, struct vlapic *source,
>      int short_hand, uint8_t dest, uint8_t dest_mode);
> 
> +struct vlapic *vlapic_lowest_vcpu(
> +    struct domain *d, struct vlapic *source,
> +    int short_hand, uint8_t dest, uint8_t dest_mode);
> +
>  bool_t vlapic_match_dest(
>      struct vlapic *target, struct vlapic *source,
>      int short_hand, uint8_t dest, uint8_t dest_mode);
> 
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