Re: [Xen-devel] [PATCH v3 6/8] ARM: VGIC: factor out vgic_get_hw_irq_desc()

[Andre Przywara <andre.przywara@xxxxxxxxxx>]

Hi,

On 31/01/18 16:16, Julien Grall wrote:
> Hi,
> 
> On 24/01/18 18:10, Andre Przywara wrote:
>> At the moment we happily access the VGIC internal struct pending_irq
>> (which describes a virtual IRQ) in irq.c.
>> Factor out the actually needed functionality to learn the associated
>> hardware IRQ and move that into gic-vgic.c to improve abstraction.
>>
>> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxxxxx>
>> Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
>> ---
>>   xen/arch/arm/gic-vgic.c    | 15 +++++++++++++++
>>   xen/arch/arm/irq.c         |  7 ++-----
>>   xen/include/asm-arm/vgic.h |  2 ++
>>   3 files changed, 19 insertions(+), 5 deletions(-)
>>
>> diff --git a/xen/arch/arm/gic-vgic.c b/xen/arch/arm/gic-vgic.c
>> index d44e4dacd3..3ad98dcd3a 100644
>> --- a/xen/arch/arm/gic-vgic.c
>> +++ b/xen/arch/arm/gic-vgic.c
>> @@ -411,6 +411,21 @@ void gic_dump_vgic_info(struct vcpu *v)
>>           printk("Pending irq=%d\n", p->irq);
>>   }
>>   +struct irq_desc *vgic_get_hw_irq_desc(struct domain *d, struct vcpu
>> *v,
>> +                                      unsigned int virq)
>> +{
>> +    struct pending_irq *p;
>> +
>> +    if ( !v )
>> +        v = d->vcpu[0];
> 
> I dislike this new function in the current state. Let's imagine someone
> decide to pass a PPI but no vCPU. The vCPU would now be default to vCPU0
> and potentially returning the wrong irq_desc (imagine PPI passthrough
> such as for the vtimer).
> 
> So the code needs at least checking the vCPU is passed in the case of a
> PPI. I would be happy with an ASSERT().

Yeah, good point. Something like ASSERT(!v && virq >= 32), I guess?

Cheers,
Andre.

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