What is Security Exception (#SX)?
Posted: Sat May 24, 2014 11:46 pm
I saw Security Exception (#SX) in http://wiki.osdev.org/Exceptions. What's that? I've never heard about this...
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( http://www.mimuw.edu.pl/~vincent/lectur ... cation.pdf }3.3 Security Exception (#SX)
The Security Exception fault signals security-sensitive events that occur while executing the VMM, in the form of an exception so that the VMM may take appropriate action. (A VMM would typically intercept comparable sensitive events in the guest.) In the current implementation, the only use of the #SX is to redirect external INITs into an exception so that the VMM may — among other possibilities — destroy sensitive information before re-issuing the INIT, this time without redirection. (The INIT redirection is controlled by the VM_CR.R_INIT bit.)
The #SX exception dispatches to vector 30, and behaves like other fault-class exceptions such as General Protection Fault (#GP). The #SX exception pushes an error code. The only error code currently defined is 1, and indicates redirection of INIT has occurred.
The #SX exception is a contributory fault.