vmm_vwrite
cnt = vmm_vwrite(bd->bd_vmm, bd->bd_curcpu, bd->bd_defseg, buf,
cnt = vmm_vwrite(bd->bd_vmm, bd->bd_curcpu, VMM_DESC_CS, buf,
cnt = vmm_vwrite(bd->bd_vmm, bd->bd_curcpu, VMM_DESC_SS, buf,
ssize_t vmm_vwrite(vmm_t *, int, int, const void *, size_t, uintptr_t);