[PATCH 4.14 60/68] ptp_kvm: probe for kvm guest availability

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Joao Martins <joao.m.martins@xxxxxxxxxx>

commit 001f60e1f662a6dee1630a2915401aaf5959d479 upstream.

In the event of moving pvclock_pvti_cpu0_va() definition to common
pvclock code, this function would return a value on non KVM guests.
Later on this would fail with a GPF on ptp_kvm_init when running on a
Xen guest. Therefore, ptp_kvm_init() should check whether it is running
in a KVM guest.

Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
Acked-by: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/ptp/ptp_kvm.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/ptp/ptp_kvm.c
+++ b/drivers/ptp/ptp_kvm.c
@@ -178,6 +178,9 @@ static int __init ptp_kvm_init(void)
 {
 	long ret;
 
+	if (!kvm_para_available())
+		return -ENODEV;
+
 	clock_pair_gpa = slow_virt_to_phys(&clock_pair);
 	hv_clock = pvclock_pvti_cpu0_va();