For ARM, The SMC instruction is used to generate a synchronous
exception that is handled by Secure Monitor code running in EL3.
In the ARM architecture, synchronous control is transferred between
the normal Non-secure state and the Secure state through Secure
Monitor Call exceptions. SMC exceptions are generated by the SMC
instruction, and handled by the Secure Monitor.The operation of
the Secure Monitor is determined by the parameters that are passed
in through registers.
For ACRN, Hypervisor will simulate SMC by hypercall to switch vCPU
State between Normal World and Secure World.
There are 4 registers(RDI, RSI, RDX, RBX) reserved for paramters
passing between Normal World and Secure World.
Signed-off-by: Qi Yadong <yadong.qi@intel.com>
