On 24.06.2013, at 16:31, Anthony Liguori wrote: > "Michael S. Tsirkin" <m...@redhat.com> writes: > >> On Mon, Jun 24, 2013 at 08:34:52AM -0500, Anthony Liguori wrote: >>> Gleb Natapov <g...@redhat.com> writes: >>> >>> Isn't this more or less what Avi's previous proposal was around changing >>> the APIC interfaces to userspace? >>> >>> Regards, >>> >>> Anthony Liguori >> >> While that's not very elegant, I think we can use the existing >> interface for this: just encode things in a fake >> "msi message" in the format that kernel expects. > > This is, in fact, exactly what we do today. The MSI interfaces aren't > for MSI. They are for sending messages to the APIC bus. What we should > do is: > > #define KVM_SIGNAL_LAPIC KVM_SIGNAL_MSI > #define KVM_IRQ_ROUTING_LAPIC KVM_IRQ_ROUTING_MSI > > And switch to using the new #defines in QEMU. That would make it more > obvious where we need to refactor things. We currently hard code > routing via a local APIC with MSI. We need to change this into a bus > specific function that can choose the right interface. > > I think Power is fine with just doing all routing through the irqchip > interface. We may need other routing interfaces for other architectures > though.
I'm not quite sure what problem exactly you're trying to solve here. The main user of MSI injects through irqfd are in the kernel and definitely want a fast path to inject those without any involvement of QEMU at all. Alex
