NextRIP is consumed on VMRUN as the return address pushed onto the
stack for injected soft exceptions/interrupts. nsvm_vmcb_prepare4vmrun()
builds n2vmcb from the virtual VMCB on every entry to the L2 guest, but
never copied this field, leaving n2vmcb->nextrip stale. Injecting an
event in this state can wedge the L2 vCPU, as the APM does not define
behaviour for a VMRUN with a garbage NextRIP.
Nested virt is only offered on NRIPS-capable hardware, and NRIPS is
required to be advertised to L1 (see start_nested_svm()), so the L1
hypervisor is required to keep NextRIP correct. Therefore no
conditional logic is needed here; an unconditional sync suffices.
Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Chunjie Zhu <chunjie.zhu@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
