Re: [Xen-devel] [PATCH v2 08/21] xen/arm: Initialize the virtual GIC later

[Julien Grall <julien.grall@xxxxxxxxxx>]

On 29/08/14 15:49, Andrii Tseglytskyi wrote:
> On Fri, Aug 29, 2014 at 9:57 PM, Julien Grall <julien.grall@xxxxxxxxxx> wrote:
> > You will have to modify the function for your purpose. If you plan to PIRQ
> > == VIRQ every time, you could do smth like:
> >
> >
> > d->arch.vgic.nr_spis = gic_number_lines() - 32;
> >
> > I assume, you already modified vgic_allocate_irq to return directly the
> > pirq, and do nothing in vgic_free_irq.
> Yes, locally I did the same as you mentioned, but I'm thinking about
> solution which will allow me to have 1 to 1 irq mapping and which will
> be acceptable for Xen mainline.
IHMO, the best solution would adding a boolean in the new DOMCTL to 
specify if we want to use PIRQ == VIRQ or not.
Then you will have to modify vgic_allocate_irq to return the physical 
IRQ if the domain as this new option enabled.
> My local diff is:
>
> diff --git a/xen/arch/arm/physdev.c b/xen/arch/arm/physdev.c
> index 9333aa0..50ff100 100644
> --- a/xen/arch/arm/physdev.c
> +++ b/xen/arch/arm/physdev.c
> @@ -46,16 +46,13 @@ static int physdev_map_pirq(domid_t domid, int
> type, int index, int *pirq_p)
>
>       virq = vgic_allocate_virq(d, irq);
>       ret = -EMFILE;
>       if ( virq == -1 )
>           goto free_domain;
>
> -    ret = route_irq_to_guest(d, virq, irq, "routed IRQ");
> +    ret = route_irq_to_guest(d, irq, irq, "routed IRQ");
With this change you may have some issue when unmap_pirq is used. I 
would modify vgic_allocate_irq to always return the physical IRQ number.
The code will be also more clean.

--
Julien Grall

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