On 21 October 2015 at 15:41, Pavel Fedin <p.fe...@samsung.com> wrote: > Hello! > >> I just wanted to understand. I don't have any preferences. > > In other words, in short: spec says that ITS is optional, so > we can implement it as a separate component, which gets attached > to the GIC using some specified interface. It's not a problem > to design such an interface. Actually, i believe real HW does > the same thing.
For hw it's a design choice: hardware can either have the ITS as an extra component on the side that only talks to the redistributors via (impdef) redistributor registers; or it can be an integrated part of the GIC that's just directly connected internally. For QEMU we could in theory do either; I was leaning towards direct connection just because on the KVM side the in-kernel GIC isn't going to separate them out as two distinct things. But even there we can as you say sensibly model the ITS as its own QOM object with a fairly well-defined interface to the rest of the GIC. thanks -- PMM
