target/i386: kvm: Fix when nested state is needed for migration

target/i386: kvm: Fix when nested state is needed for migration

When vCPU is in VMX operation and enters SMM mode,
it temporarily exits VMX operation but KVM maintained nested-state
still stores the VMXON region physical address, i.e. even when the
vCPU is in SMM mode then (nested_state->hdr.vmx.vmxon_pa != -1ull).

Therefore, there is no need to explicitly check for
KVM_STATE_NESTED_SMM_VMXON to determine if it is necessary
to save nested-state as part of migration stream.

Reviewed-by: Karl Heubaum <[email protected]>
Signed-off-by: Liran Alon <[email protected]>
Message-Id: <20190624230514[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>