linux-toradex.git/drivers/hv/hv_util.c, branch v4.13-rc5

hv_utils: fix TimeSync work on pre-TimeSync-v4 hosts

2017-05-25T13:42:42+00:00

It was found that ICTIMESYNCFLAG_SYNC packets are handled incorrectly
on WS2012R2, e.g. after the guest is paused and resumed its time is set
to something different from host's time. The problem is that we call
adj_guesttime() with reftime=0 for these old hosts and we don't account
for that in 'if (adj_flags & ICTIMESYNCFLAG_SYNC)' branch and
hv_set_host_time().

While we could've solved this by adding a check like
'if (ts_srv_version > TS_VERSION_3)' to hv_set_host_time() I prefer
to do some refactoring. We don't need to have two separate containers
for host samples, struct host_ts which we use for PTP is enough.

Throw away 'struct adj_time_work' and create hv_get_adj_host_time()
accessor to host_ts to avoid code duplication.

Fixes: 3716a49a81ba ("hv_utils: implement Hyper-V PTP source")
Signed-off-by: Vitaly Kuznetsov 
Signed-off-by: K. Y. Srinivasan 
Signed-off-by: Greg Kroah-Hartman

hv_utils: drop .getcrosststamp() support from PTP driver

2017-05-25T13:42:42+00:00

Turns out that our implementation of .getcrosststamp() never actually
worked. Hyper-V is sending time samples every 5 seconds and this is
too much for get_device_system_crosststamp() as it's interpolation
algorithm (which nobody is currently using in kernel, btw) accounts
for a 'slow' device but we're not slow in Hyper-V, our time reference
is too far away.

.getcrosststamp() is not currently used, get_device_system_crosststamp()
almost always returns -EINVAL and client falls back to using PTP_SYS_OFFSET
so this patch doesn't change much. I also tried doing interpolation
manually (e.g. the same way hv_ptp_gettime() works and it turns out that
we're getting even lower quality:

PTP_SYS_OFFSET_PRECISE with manual interpolation:
* PHC0                     0   3    37     4  -3974ns[-5338ns] +/-  977ns
* PHC0                     0   3    77     7  +2227ns[+3184ns] +/-  576ns
* PHC0                     0   3   177    10  +3060ns[+5220ns] +/-  548ns
* PHC0                     0   3   377    12  +3937ns[+4371ns] +/- 1414ns
* PHC0                     0   3   377     6   +764ns[+1240ns] +/- 1047ns
* PHC0                     0   3   377     7  -1210ns[-3731ns] +/-  479ns
* PHC0                     0   3   377     9   +153ns[-1019ns] +/-  406ns
* PHC0                     0   3   377    12   -872ns[-1793ns] +/-  443ns
* PHC0                     0   3   377     5   +701ns[+3599ns] +/-  426ns
* PHC0                     0   3   377     5   -923ns[ -375ns] +/- 1062ns

PTP_SYS_OFFSET:
* PHC0                     0   3     7     5    +72ns[+8020ns] +/-  251ns
* PHC0                     0   3    17     5   -885ns[-3661ns] +/-  254ns
* PHC0                     0   3    37     6   -454ns[-5732ns] +/-  258ns
* PHC0                     0   3    77    10  +1183ns[+3754ns] +/-  164ns
* PHC0                     0   3   377     5   +579ns[+1137ns] +/-  110ns
* PHC0                     0   3   377     7   +501ns[+1064ns] +/-   96ns
* PHC0                     0   3   377     9  +1641ns[+3342ns] +/-  106ns
* PHC0                     0   3   377     8    -47ns[  +77ns] +/-  160ns
* PHC0                     0   3   377     5    +54ns[ +107ns] +/-  102ns
* PHC0                     0   3   377     8   -354ns[ -617ns] +/-   89ns

This fact wasn't noticed during the initial testing of the PTP device
somehow but got revealed now. Let's just drop .getcrosststamp()
implementation for now as it doesn't seem to be suitable for us.

Signed-off-by: Vitaly Kuznetsov 
Signed-off-by: K. Y. Srinivasan 
Signed-off-by: Greg Kroah-Hartman

Drivers: hv: util: don't forget to init host_ts.lock

2017-03-16T07:42:00+00:00

Without the patch, I always get a "BUG: spinlock bad magic" warning.

Fixes: 3716a49a81ba ("hv_utils: implement Hyper-V PTP source")

Signed-off-by: Dexuan Cui 
Cc: Vitaly Kuznetsov 
Cc: "K. Y. Srinivasan" 
Cc: Haiyang Zhang 
Cc: Stephen Hemminger 
Signed-off-by: K. Y. Srinivasan 
Signed-off-by: Greg Kroah-Hartman

vmbus: add direct isr callback mode

2017-02-14T18:20:35+00:00

Change the simple boolean batched_reading into a tri-value.
For future NAPI support in netvsc driver, the callback needs to
occur directly in interrupt handler.

Batched mode is also changed to disable host interrupts immediately
in interrupt routine (to avoid unnecessary host signals), and the
tasklet is rescheduled if more data is detected.

Signed-off-by: Stephen Hemminger 
Signed-off-by: K. Y. Srinivasan 
Signed-off-by: Greg Kroah-Hartman

Drivers: hv: util: Fix a typo

2017-02-10T14:40:19+00:00

Fix a typo.

Signed-off-by: K. Y. Srinivasan 
Signed-off-by: Greg Kroah-Hartman

hv_utils: implement Hyper-V PTP source

2017-02-10T14:40:19+00:00

With TimeSync version 4 protocol support we started updating system time
continuously through the whole lifetime of Hyper-V guests. Every 5 seconds
there is a time sample from the host which triggers do_settimeofday[64]().
While the time from the host is very accurate such adjustments may cause
issues:
- Time is jumping forward and backward, some applications may misbehave.
- In case an NTP server runs in parallel and uses something else for time
  sync (network, PTP,...) system time will never converge.
- Systemd starts annoying you by printing "Time has been changed" every 5
  seconds to the system log.

Instead of doing in-kernel time adjustments offload the work to an
NTP client by exposing TimeSync messages as a PTP device. Users may now
decide what they want to use as a source.

I tested the solution with chrony, the config was:

 refclock PHC /dev/ptp0 poll 3 dpoll -2 offset 0

The result I'm seeing is accurate enough, the time delta between the guest
and the host is almost always within [-10us, +10us], the in-kernel solution
was giving us comparable results.

I also tried implementing PPS device instead of PTP by using not currently
used Hyper-V synthetic timers (we use only one of four for clockevent) but
with PPS source only chrony wasn't able to give me the required accuracy,
the delta often more that 100us.

Signed-off-by: Vitaly Kuznetsov 
Signed-off-by: K. Y. Srinivasan 
Signed-off-by: Greg Kroah-Hartman

Drivers: hv: Log the negotiated IC versions.

2017-01-31T10:05:59+00:00

Log the negotiated IC versions.

Signed-off-by: Alex Ng 
Signed-off-by: K. Y. Srinivasan 
Signed-off-by: Greg Kroah-Hartman

Drivers: hv: vmbus: Use all supported IC versions to negotiate

2017-01-31T10:05:59+00:00

Previously, we were assuming that each IC protocol version was tied to a
specific host version. For example, some Windows 10 preview hosts only
support v3 TimeSync even though driver assumes v4 is supported by all
Windows 10 hosts.

The guest will stop trying to negotiate even though older supported
versions may still be offered by the host.

Make IC version negotiation more robust by going through all versions
that are supported by the guest.

Fixes: 3da0401b4d0e ("Drivers: hv: utils: Fix the mapping between host
version and protocol to use")

Reported-by: Rolf Neugebauer 
Signed-off-by: Alex Ng 
Signed-off-by: K. Y. Srinivasan 
Signed-off-by: Greg Kroah-Hartman

hv_util: switch to using timespec64

2017-01-31T10:05:58+00:00

do_settimeofday() is deprecated, use do_settimeofday64() instead.

Signed-off-by: Vitaly Kuznetsov 
Acked-by: John Stultz 
Acked-by: Thomas Gleixner 
Signed-off-by: K. Y. Srinivasan 
Signed-off-by: Greg Kroah-Hartman

Drivers: hv: util: Use hv_get_current_tick() to get current tick

2017-01-20T13:48:03+00:00

As part of the effort to interact with Hyper-V in an instruction set
architecture independent way, use the new API to get the current
tick.

Signed-off-by: K. Y. Srinivasan 
Signed-off-by: Greg Kroah-Hartman