On 19.12.2017 04:07, Jim Mattson wrote: > The other unfortunate thing about flushing the "current" VMCS12 state > to guest memory on each L2->userspace transition is that much of this > state is in the VMCS02. So,it's not just a matter of writing a > VMCS12_SIZE blob to guest memory; first, the cached VMCS12 has to be > updated from the VMCS02 by calling sync_vmcs12(). This will be > particularly bad for double-nesting, where L1 kvm has to take all of > those VMREAD VM-exits. > > If you still prefer this method, I will go ahead and do it, but I > remain opposed. This can be easily solved by letting QEMU trigger a pre-migration ioctl. (FLUSH_NESTED_VMCS). So that shouldn't really be the problem. -- Thanks, David / dhildenb