Re: [PATCH] KVM: VMX cannot yet handle migration-after-preemption, so disable it

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Gregory Haskins wrote:
> This patch applies to the preempt-hooks branch to enable KVM to function
> properly on VMX.  With preemption enabled, the KVM context can get scheduled
> out at arbitrary points.  The preempt-hooks allow us to correctly restore
> the host state while being preemptible, but preemption causes problems on the
> schedule-in side if the vcpu-task migrates to a new pCPU.
>
> Ideally we can handle the migration scenario better (patch for this in
> progress).  However, this patch provides correctness in the interim at the
> expense of a small amount of flexibility. E.g. we can only migrate when the
> vcpu_lock is not held.
>
>   

I'd rather wait for the real fix, especially as this is an experimental
branch.  Can you provide details of the issue?

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


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