VMPTRLD

if not in_vmx:
    fault(UD)
if vmx_nonroot:
    vm_exit(21)                  # the hypervisor emulates it
if CPL > 0:
    fault(GP, 0)
p = src.read()                   # a physical address
basic = msr[IA32_VMX_BASIC]
w = maxphyaddr                   # the physical-address width, or
if basic >> 48 & 1:              # 32 bits where IA32_VMX_BASIC[48]
    w = 32                       # says so
if p & 0xFFF or p >> w:
    vm_fail(9)                   # not 4-KByte aligned, or past the
                                 # physical-address width
elif p == vmxon_ptr:
    vm_fail(10)                  # the VMXON region is no VMCS
else:
    r = phys_read(p, 32)         # the region's revision identifier
    caps = msr[IA32_VMX_PROCBASED_CTLS2]
    shadow = caps >> 46 & 1      # VMCS shadowing may be 1
    if r & 0x7FFFFFFF != basic & 0x7FFFFFFF:
        vm_fail(11)
    elif r >> 31 and not shadow:
        vm_fail(11)              # a shadow VMCS, which only VMCS
                                 # shadowing uses
    else:
        current_vmcs = p
        vm_succeed()