Re: Multiple IRQ's in HVM for Windows

[Keir Fraser <keir.fraser@eu.citrix.com>]

On 26/12/2008 10:15, "James Harper" <james.harper@bendigoit.com.au> wrote:

> The above probably shows a lack of understanding on my part about how
> events are delivered into hvm domains as interrupts - can you point me
> to what files I need to look at to understand this better? Then maybe
> I'll have a better idea about what I'm asking for (or I'll understand
> why it won't work :)

Currently all event channels are tied together as a single interrupt line,
which can be configured to appear to come from the xen-platform fake PCI
device. We could duplicate that device so you could have a PCI INTx line per
CPU. Or duplicate it so that you could have a PCI INTx line per event
channel (or at least barber-pole onto such a set of INTx lines).

Or we could bypass the INTx emulation entirely, and deliver per-cpu
event_pending status to that HVM VCPU's local APIC, on a pre-registered
interrupt vector (this is most like MSI, except the interrupt wouldn't be
coming from a PCI device, although we could perhaps even fake that out too).

There's quite a few options.

 -- Keir