Re: [PATCH 20/29] KVM: x86: add planes support for interrupt delivery

[Paolo Bonzini]

On 6/6/25 18:30, Sean Christopherson wrote:
> On Tue, Apr 01, 2025, Paolo Bonzini wrote:
> > Plumb the destination plane into struct kvm_lapic_irq and propagate it
> > everywhere.  The in-kernel IOAPIC only targets plane 0.
>
> Can we get more aggressive and make KVM_CREATE_IRQCHIP mutually exclusive with
> planes?  AIUI, literally every use case for planes is for folks that run split
> IRQ chips.

Maybe, but is there any added complexity other than the "= {0}" to 
initialize the new field.  Ready to be proven wrong but I do think 
that's one thing that just works.

> And we should require an in-kernel local APIC to create a plane.

I don't think it's needed either; if anything the complexity of patch 25 
isn't needed with userspace local APIC.

Paolo