Re: [kvm-devel] Problem with SMP boot

[Avi K. <av...@qu...>]

Matthew Hall wrote:
> Avi Kivity wrote:
>   
>> kvm only supports uniprocessor guests at this time.
>>     
>
> Out of interest, if/when

when.


>  kvm supports smp guests aswell as hosts would 
> the guest be presented with a multiple virtual or physical cpu's?
> Ie. If the guest has multiple virtual cpu's the process would only run 
> as a single task which would then affine to a single cpu on a multiple 
> cpu host.
>
> So could kvm let an smp guest share the physical cpu's the host has?
>   

kvm maps a guest vcpu to a host thread.  In turn, the host scheduler 
maps host threads to host cpus, so the mapping of vcpus to cpus depends 
on resource availability: if you have enough cpus, the scheduler will 
assign each vcpu to a separate cpu.

The user will also be able to affect the mapping by binding vcpu threads 
to specific processors.


-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.