GETSEC

if not cr4 >> 14 & 1:
    fault(UD)                    # CR4.SMXE clear (and on AMD's
                                 # processors, which have no SMX)
if vmx_nonroot:
    vm_exit(11)                  # the hypervisor emulates it
n = eax                          # the leaf
caps = smx_capabilities(0)       # bits 8:2: the leaves 2 to 8
if n > 30 or n and not caps >> n & 1:
    fault(UD)                    # a leaf the processor lacks
if n == 0:
    eax = smx_capabilities(ebx)  # CAPABILITIES, at any CPL: bit 0
                                 # a TXT chipset; bit 31, more at
                                 # the next EBX
elif n == 6:
    leaf_function(n)             # PARAMETERS, at any CPL: the
                                 # parameter EBX selects, in EAX,
                                 # EBX and ECX
elif CPL > 0:
    fault(GP, 0)
else:
    leaf_function(n)             # ENTERACCS (2), EXITAC (3), SENTER
                                 # (4), SEXIT (5), SMCTRL (7) and
                                 # WAKEUP (8), each with checks of
                                 # its own (#GP(0)) on its page