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

[Jan Kiszka]

Am 12.01.2011 11:22, Avi Kivity wrote:
> 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.  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.
> 

Exactly.

So we can either "infect" the whole device tree with kvm (or maybe a
more generic accelerator structure that also deals with Xen) or we need
to pull the reference inside the device's init function from some global
service (kvm_get_state).

Jan

PS: I started refreshing my whole patch series with the two
controversial patches removed. Will send out later so that we can
proceed with merging the critical bits, specifically all the bug fixes.

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