vm_hpet_cap
struct vm_hpet_cap cap;
bzero(&cap, sizeof(struct vm_hpet_cap));
_IOR('v', IOCNUM_GET_HPET_CAPABILITIES, struct vm_hpet_cap)
vhpet_getcap(struct vm_hpet_cap *cap)
int vhpet_getcap(struct vm_hpet_cap *cap);
error = vhpet_getcap((struct vm_hpet_cap *)data);
struct vm_hpet_cap;