KVM: nVMX: Ignore SIPI that arrives in L2 when vCPU is not in WFS

KVM: nVMX: Ignore SIPI that arrives in L2 when vCPU is not in WFS

Fall through to handling other pending exception/events for L2 if SIPI
is pending while the CPU is not in Wait-for-SIPI.  KVM correctly ignores
the event, but incorrectly returns immediately, e.g. a SIPI coincident
with another event could lead to KVM incorrectly routing the event to L1
instead of L2.

Fixes: 20beab7c2604 ("KVM: x86: emulate wait-for-SIPI and SIPI-VMExit")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20220830231614.3580124-11-seanjc@google.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>