x86/hvm: don't discard the SW/HW event distinction from the emulator

x86/hvm: don't discard the SW/HW event distinction from the emulator

Injecting emulator software events as hardware exceptions results in a bypass
of DPL checks.  As the emulator doesn't perform DPL checks itself, guest
userspace is capable of bypassing DPL checks and injecting arbitrary events.

Propagating software event information from the emulator allows VMX to now
properly inject software events, including DPL and presence checks, as well
correct fault/trap frames.

Reported-by: Andrei LUTAS <vlutas@bitdefender.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Tested-by: Andrei LUTAS <vlutas@bitdefender.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>