Re: KVM Nested L2 guest startup problems

From: Paolo Bonzini
Date: Wed May 07 2014 - 07:37:26 EST


Il 07/05/2014 13:16, Abel Gordon ha scritto:
> PLE should be left enabled, I think.
Well... the PLE settings L0 uses to run L1 (vmcs01) may be different
than the PLE settings L1 configured to run L2 (vmcs12).
For example, L0 can use a ple_gap to run L1 that is bigger than the
ple_gap L1 configured to run L2. Or L0 can use a ple_window to run L1
that is smaller than the ple_window L1 configured to run L2.

That's correct. We should leave PLE enabled while running L2, but hide the feature altogether from L1.

Paolo

So seems PLE should never be exposed to L1 or an appropriate nested
handling needs to be implemented. Note the handling may become complex
because in some cases a PLE exit from L2 should be handled directly by
L0 and not passed to L1... remember nested preemption timer support :)
?

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