Re: [Xen-devel] [RFC PATCH] xen/arm: Deliver interrupts to vcpu specified in IROUTER

[Vijay Kilari <vijay.kilari@xxxxxxxxx>]

On Mon, Sep 8, 2014 at 7:33 PM, Vijay Kilari <vijay.kilari@xxxxxxxxx> wrote:
> On Mon, Sep 8, 2014 at 7:17 PM, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
>> On Mon, 2014-09-08 at 19:11 +0530, Vijay Kilari wrote:
>>
>> Why have we dropped the list?
>
> I have not dropped the list. I still see list in my email.
>
>>
>>> Hi Stefano,
>>>
>>>  Apart from your comments below, I encounter below scenario.
>>>
>>> The below function vgic_irq_rank() in vgic.c is not generic. The rank is 
>>> always
>>> depends on register type it is going to access. So it cannot be
>>> just hardcoded.
>>>
>>> struct vgic_irq_rank *(struct vcpu *v, unsigned int irq)
>>> {
>>>     return vgic_rank_offset(v, 8, irq, DABT_WORD);
>>> }
>>>
>>> This function works ok for GIC v2. But this cannot be used for
>>> GICv3 to access registers like IROUTER which are u64. The rank
>>> calcuation goes wrong and there by takes wrong rank lock.
>>
>> This sounds to me like a bug which should be fixed. A rank is just a
>> group of 32 consecutive IRQs and their associated register values, it
>> shouldn't matter whether those registers are 8-, 16-, 32- or 64-bits.
>
>  Now I think of creating a callback to return the right rank for given irq
> based on v2 or v3. This will fix and keep the old code intact.

This should fix the issue.

 struct vgic_irq_rank *vgic_rank_irq(struct vcpu *v, unsigned int irq)
 {
-    return vgic_rank_offset(v, 8, irq, DABT_WORD);
+    int rank = irq/32;

+    if ( rank == 0 )
+        return v->arch.vgic.private_irqs;
+    else if ( rank <= DOMAIN_NR_RANKS(v->domain) )
+        return &v->domain->arch.vgic.shared_irqs[rank - 1];
+    else
+        return NULL;
}

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