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| author | Vineeth Pillai <viremana@linux.microsoft.com> | 2020-08-21 18:25:23 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-09-09 20:14:09 +0300 |
| commit | 6a725c83a08d41f2bc1630835712a4edc2e6caad (patch) | |
| tree | b8535c742cbe4a8df69cec1b183fce6d05cb6ab6 /drivers/hv | |
| parent | 4f3ffd5fcbf77a0bb497a89c1b28c2a4532a9101 (diff) | |
| download | linux-6a725c83a08d41f2bc1630835712a4edc2e6caad.tar.xz | |
hv_utils: return error if host timesysnc update is stale
[ Upstream commit 90b125f4cd2697f949f5877df723a0b710693dd0 ]
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 <viremana@linux.microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20200821152523.99364-1-viremana@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/hv')
| -rw-r--r-- | drivers/hv/hv_util.c | 46 |
1 files 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 = { |