Re: [RFC] Unify KVM kernel-space and user-space code into a single project

Alexander Graf
2010-03-18T09:24:37Z

On 18.03.2010, at 09:56, Ingo Molnar wrote:

>
> * Avi Kivity <avi@redhat.com> wrote:
>
>> On 03/17/2010 10:10 AM, Ingo Molnar wrote:
>>>
>>>> It's about who owns the user interface.
>>>>
>>>> If qemu owns the user interface, than we can satisfy this in a very
>>>> simple way by adding a perf monitor command. If we have to support third
>>>> party tools, then it significantly complicates things.
>>>
>>> Of course illogical modularization complicates things 'significantly'.
>>
>> Who should own the user interface then?
>
> If qemu was in tools/kvm/ then we wouldnt have such issues. A single patch (or
> series of patches) could modify tools/kvm/, arch/x86/kvm/, virt/ and
> tools/perf/.

It's not a 1:1 connection. There are more users of the KVM interface. To name a few I'm aware of:

- Mac-on-Linux (PPC)
- Dolphin (PPC)
- Xenner (x86)
- Kuli (s390)

Having a clear userspace interface is the only viable solution there. And if you're interested, look at my MOL enabling patch. It's less than 500 lines of code.

The kernel/userspace interface really isn't the difficult part. Getting device emulation working properly, easily and fast is.

Alex