Re: [Qemu-devel] Should the i8259 devices remain no-user?

[Paolo Bonzini <pbonzini@redhat.com>]

Il 15/10/2013 14:43, Markus Armbruster ha scritto:
> Paolo, or maybe Andreas,
> 
> To go beyond RFC with this series, I need to explain why isa-i8259 and
> kvm-i8259 cannot_instantiate_with_device_add_yet, or drop that.  I'd
> appreciate your help.
> 
> Both are derived from TYPE_PIC_COMMON, which is derived from
> TYPE_ISA_DEVICE.
> 
> I figure isa-i8259 cannot_instantiate_with_device_add_yet, because it
> sets global isa_pic and slave_pic.  slave_pic appears to be a lame way
> to wire the slave PIC to the master PIC behind QOM's back.  isa_pic
> appears to be a lame way to wire the master PIC to whatever it needs to
> be wired to.  Is that a fair description?

Yes.

> If yes, is it sufficient reason for
> cannot_instantiate_with_device_add_yet?
> 
> kvm-i8259 is the same device implemented with kernel support.  Does it
> have its own reason for cannot_instantiate_with_device_add_yet?
> 
> If not, should it keep cannot_instantiate_with_device_add_yet for
> symmetry with isa-i8259?

Both i8259 implementations have to be matched with an appropriate array
of qemu_irqs, such as the one returned by kvm_i8259_init.  I think this
is the reason why kvm-i8259 cannot be instantiated from the command-line.

Paolo