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

Avi Kivity
2010-03-23T16:39:58Z

On 03/23/2010 04:06 PM, Joerg Roedel wrote:
> On Mon, Mar 22, 2010 at 05:06:17PM -0500, Anthony Liguori wrote:
>
>> There always needs to be a system wide entity. There are two ways to
>> enumerate instances from that system wide entity. You can centralize
>> the creation of instances and there by maintain an list of current
>> instances. You can also allow instances to be created in a
>> decentralized manner and provide a standard mechanism for instances to
>> register themselves with the system wide entity.
>>
> And this system wide entity is the kvm module. It creates instances of
> 'struct kvm' and destroys them. I see no problem if we just attach a
> name to every instance with a good default value like kvm0, kvm1 ... or
> guest0, guest1 ... User-space can override the name if it wants. The kvm
> module takes care about the names being unique.
>

So, two users can't have a guest named MyGuest each? What about
namespace support? There's a lot of work in virtualizing all kernel
namespaces, you're adding to that. What about notifications when guests
are added or removed?

> This is very much the same as network card numbering is implemented in
> the kernel.
> Forcing perf to talk to qemu or even libvirt produces to much overhead
> imho. Instrumentation only produces useful results with low overhead.
>
>

It's a setup cost only.

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