Re: [Qemu-devel] [PATCH 28/35] kvm: x86: Introduce kvmclock device to save/restore its state

[Markus Armbruster]

Avi Kivity <address@hidden> writes:

> On 01/11/2011 03:54 PM, Anthony Liguori wrote:
>>
>> Right, we should introduce a KVMBus that KVM devices are created on.
>> The devices can get at KVMState through the BusState.
>
> There is no kvm bus in a PC (I looked).  We're bending the device
> model here because a device is implemented in the kernel and not in
> userspace.  An implementation detail is magnified beyond all
> proportions.
>
> An ioapic that is implemented by kvm lives in exactly the same place
> that the qemu ioapic lives in.

Exactly.  And that place is a bus.

What if the device interfaces in bus-specific ways with its parent bus?
Then we can't simply replace the parent bus by a KVM bus.  We'd need
*two* parent buses, as Jan pointed out upthread.

>                                 An assigned pci device lives on the
> PCI bus, not a KVMBus.  If we need a pointer to KVMState, then we must
> find it elsewhere, not through creating imaginary buses that don't
> exist.