Re: [PATCH for-4.14 v2 1/2] x86/passthrough: do not assert edge triggered GSIs for PVH dom0

[Jan Beulich <jbeulich@xxxxxxxx>]

On 10.06.2020 16:29, Roger Pau Monne wrote:
> @@ -186,9 +187,10 @@ void hvm_gsi_assert(struct domain *d, unsigned int gsi)
>       * to know if the GSI is pending or not.
>       */
>      spin_lock(&d->arch.hvm.irq_lock);
> -    if ( !hvm_irq->gsi_assert_count[gsi] )
> +    if ( trig == VIOAPIC_EDGE_TRIG || !hvm_irq->gsi_assert_count[gsi] )
>      {
> -        hvm_irq->gsi_assert_count[gsi] = 1;
> +        if ( trig == VIOAPIC_LEVEL_TRIG )
> +            hvm_irq->gsi_assert_count[gsi] = 1;

Btw, along the lines of how you do things here, I think ...

> @@ -196,11 +198,12 @@ void hvm_gsi_assert(struct domain *d, unsigned int gsi)
>  
>  void hvm_gsi_deassert(struct domain *d, unsigned int gsi)
>  {
> +    int trig = vioapic_get_trigger_mode(d, gsi);
>      struct hvm_irq *hvm_irq = hvm_domain_irq(d);
>  
> -    if ( gsi >= hvm_irq->nr_gsis )
> +    if ( trig <= VIOAPIC_EDGE_TRIG || gsi >= hvm_irq->nr_gsis )

... this would better have been "trig != VIOAPIC_LEVEL_TRIG", to
avoid the code being dependent upon the actual values of both
VIOAPIC_*_TRIG constants.

Jan

> -        ASSERT_UNREACHABLE();
> +        ASSERT(trig == VIOAPIC_EDGE_TRIG && gsi < hvm_irq->nr_gsis);
>          return;
>      }
>  
>