Re: [Xen-devel] [PATCH for-4.9] x86/vioapic: allow holes in the GSI range for PVH Dom0

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 17.04.17 at 18:09, <roger.pau@xxxxxxxxxx> wrote:
> @@ -601,7 +587,12 @@ int vioapic_init(struct domain *d)
>          nr_gsis += nr_pins;
>      }
>  
> -    ASSERT(hvm_domain_irq(d)->nr_gsis == nr_gsis);
> +    /*
> +     * NB: hvm_domain_irq(d)->nr_gsis is actually the highest GSI + 1, but
> +     * there might be holes in this range (ie: GSIs that don't belong to any
> +     * vIO APIC).
> +     */
> +    ASSERT(hvm_domain_irq(d)->nr_gsis >= nr_gsis);

This becomes too weak then, as you want to index the array using
the GSI (and not some compressed representation with the holes
squashed). Which in turn means the nr_gsis calculation in this
function is now wrong - you need to accumulate the maximum
base_gsi + nr_pins value here instead. With that >= will actually
be fine to use here.

Jan


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