RE: [Xen-devel] [PATCH] Fix legacy irq allocation issue

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

>>> "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx> 19.06.09 11:03 >>>
>The followed is based on old patch. Jan, is this ok?
>Signed-off-by: Jiang, Yunhong <yunhong.jiang@xxxxxxxxx>

Yes, this is how I expected it to be.

>BTW, when I working on this, I'm abit confused of the irq. I'm not sure if I 
>can assume irq is mainly for IOAPIC/PIC (i.e. something
>like gsi and is global), while pirq is just physical irq (i.e. including both 
>gsi/MSI irq)? 

"irq" should no longer refer to anything MSI related (MSI just requires a 
vector, but not an irq). "pirq" is generally meant to be the guest 
representation (even for MSI, the guest needs a pirq assigned because the event 
channel interface requires one to be passed in).

> If yes, what's the irq in PHYSDEVOP_alloc_irq_vector()? It is in fact dom0's 
> irq, however, in assign_irq_vector(), seems it is treated
>same as Xen's irq. I remember I understood that part when I begin working on 
>MSI, but seems I fogot the answer now :$

Correct, because for IO-APIC irqs a 1:1 mapping is being assumed between (dom0) 
pirq and (xen) irq. I think there's currently no real reason to break this 
assumption, even though it seems not fully correct (because not properly 
abstracted).

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel