No point in registering the device if it cannot work.
The hypercall does not advertise itself, so we have to call it.
Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
---
drivers/ptp/ptp_kvm.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/ptp/ptp_kvm.c b/drivers/ptp/ptp_kvm.c
index 0a54e8326a90..0803286ca6b7 100644
--- a/drivers/ptp/ptp_kvm.c
+++ b/drivers/ptp/ptp_kvm.c
@@ -176,12 +176,19 @@ static void __exit ptp_kvm_exit(void)
static int __init ptp_kvm_init(void)
{
+ long ret;
+
clock_pair_gpa = slow_virt_to_phys(&clock_pair);
hv_clock = pvclock_pvti_cpu0_va();
if (!hv_clock)
return -ENODEV;
+ ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, clock_pair_gpa,
+ KVM_CLOCK_PAIRING_WALLCLOCK);
+ if (ret == -KVM_ENOSYS || ret == -KVM_EOPNOTSUPP)
+ return -ENODEV:
+
kvm_ptp_clock.caps = ptp_kvm_caps;
kvm_ptp_clock.ptp_clock = ptp_clock_register(&kvm_ptp_clock.caps, NULL);
--
2.11.1
