If for any reason, host timesync messages were not processed by
the guest, hv_ptp_gettime() returns a stale value and the
caller (clock_gettime, PTP ioctl etc) has no means to know this
now. Return an error so that the caller knows about this.
Signed-off-by: Vineeth Pillai <[email protected]>
---
v2:
- Fix warnings reported by Kernel test robot <[email protected]>
- s/pr_warn/pr_warn_once/
---
drivers/hv/hv_util.c | 46 +++++++++++++++++++++++++++++++++-----------
1 file changed, 35 insertions(+), 11 deletions(-)
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index 92ee0fe4c919..1f86e8d9b018 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -282,26 +282,52 @@ static struct {
spinlock_t lock;
} host_ts;
-static struct timespec64 hv_get_adj_host_time(void)
+static inline u64 reftime_to_ns(u64 reftime)
{
- struct timespec64 ts;
- u64 newtime, reftime;
+ return (reftime - WLTIMEDELTA) * 100;
+}
+
+/*
+ * Hard coded threshold for host timesync delay: 600 seconds
+ */
+static const u64 HOST_TIMESYNC_DELAY_THRESH = 600 * (u64)NSEC_PER_SEC;
+
+static int hv_get_adj_host_time(struct timespec64 *ts)
+{
+ u64 newtime, reftime, timediff_adj;
unsigned long flags;
+ int ret = 0;
spin_lock_irqsave(&host_ts.lock, flags);
reftime = hv_read_reference_counter();
- newtime = host_ts.host_time + (reftime - host_ts.ref_time);
- ts = ns_to_timespec64((newtime - WLTIMEDELTA) * 100);
+
+ /*
+ * We need to let the caller know that last update from host
+ * is older than the max allowable threshold. clock_gettime()
+ * and PTP ioctl do not have a documented error that we could
+ * return for this specific case. Use ESTALE to report this.
+ */
+ timediff_adj = reftime - host_ts.ref_time;
+ if (timediff_adj * 100 > HOST_TIMESYNC_DELAY_THRESH) {
+ pr_warn_once("TIMESYNC IC: Stale time stamp, %llu nsecs old\n",
+ (timediff_adj * 100));
+ ret = -ESTALE;
+ }
+
+ newtime = host_ts.host_time + timediff_adj;
+ *ts = ns_to_timespec64(reftime_to_ns(newtime));
spin_unlock_irqrestore(&host_ts.lock, flags);
- return ts;
+ return ret;
}
static void hv_set_host_time(struct work_struct *work)
{
- struct timespec64 ts = hv_get_adj_host_time();
- do_settimeofday64(&ts);
+ struct timespec64 ts;
+
+ if (!hv_get_adj_host_time(&ts))
+ do_settimeofday64(&ts);
}
/*
@@ -622,9 +648,7 @@ static int hv_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
static int hv_ptp_gettime(struct ptp_clock_info *info, struct timespec64 *ts)
{
- *ts = hv_get_adj_host_time();
-
- return 0;
+ return hv_get_adj_host_time(ts);
}
static struct ptp_clock_info ptp_hyperv_info = {
base-commit: 49971e6bad2da980686368baa34039907f62b516
--
2.17.1
From: [email protected] Sent: Friday, August 21, 2020 8:25 AM
>
> If for any reason, host timesync messages were not processed by
> the guest, hv_ptp_gettime() returns a stale value and the
> caller (clock_gettime, PTP ioctl etc) has no means to know this
> now. Return an error so that the caller knows about this.
>
> Signed-off-by: Vineeth Pillai <[email protected]>
> ---
>
> v2:
> - Fix warnings reported by Kernel test robot <[email protected]>
> - s/pr_warn/pr_warn_once/
>
> ---
> drivers/hv/hv_util.c | 46 +++++++++++++++++++++++++++++++++-----------
> 1 file changed, 35 insertions(+), 11 deletions(-)
Reviewed-by: Michael Kelley <[email protected]>
On Fri, Aug 21, 2020 at 03:44:24PM +0000, Michael Kelley wrote:
> From: [email protected] Sent: Friday, August 21, 2020 8:25 AM
> >
> > If for any reason, host timesync messages were not processed by
> > the guest, hv_ptp_gettime() returns a stale value and the
> > caller (clock_gettime, PTP ioctl etc) has no means to know this
> > now. Return an error so that the caller knows about this.
> >
> > Signed-off-by: Vineeth Pillai <[email protected]>
> > ---
> >
> > v2:
> > - Fix warnings reported by Kernel test robot <[email protected]>
> > - s/pr_warn/pr_warn_once/
> >
> > ---
> > drivers/hv/hv_util.c | 46 +++++++++++++++++++++++++++++++++-----------
> > 1 file changed, 35 insertions(+), 11 deletions(-)
>
> Reviewed-by: Michael Kelley <[email protected]>
Applied to hyperv-fixes. Thanks.