HYPERVISOR_sysctl
if ((xerr = HYPERVISOR_sysctl(&op)) != 0)
if ((rc = HYPERVISOR_sysctl(&xs)) >= 0) {
error = HYPERVISOR_sysctl(&dop);
error = HYPERVISOR_sysctl(&dop);
error = HYPERVISOR_sysctl(&dop);
error = HYPERVISOR_sysctl(&op);
ret = HYPERVISOR_sysctl(&op);
extern long HYPERVISOR_sysctl(xen_sysctl_t *);