Re: [Qemu-devel] [PATCH RFC] kvm: ignore apic polarity

[Paolo Bonzini]

Il 28/02/2014 05:55, Michael S. Tsirkin ha scritto:
> Why?
>
> We already have different ACPI tables for TCG vs KVM.
> Specifically apic interrupt override flag in MADT is set
> for KVM but not TCG.

It used to be this way, but

  bool kvm_allows_irq0_override(void)
  {
      return !kvm_irqchip_in_kernel() || kvm_has_gsi_routing();
  }

means that these days it is usually set for both TCG and KVM.

> As KVM hardware differs from TCG, I expect them to move
> further apart with time.

I don't expect this, because there are some kind of guests that people 
will unknowingly end up running with TCG---for example libguestfs.  So 
minimizing the differences in hardware between KVM and TCG _is_ a goal.

> Or we can do a patch like we did for kvm and ignore polarity,
> treating levels as logical rather than physical.

Yes.

Paolo