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Vitaly Kuznetsov 3716a49a81 hv_utils: implement Hyper-V PTP source 
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 <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 		2017-02-10 15:40:19 +01:00
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accessibility
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acpi ACPI fixes for v4.10-rc6 2017-01-26 17:27:00 -08:00
amba
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android
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ata ata: sata_mv:- Handle return value of devm_ioremap. 2017-01-06 15:45:32 -05:00
atm Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
auxdisplay auxdisplay: fix new ht16k33 build errors 2017-01-11 09:27:30 +01:00
base Char/misc driver fixes for 4.10-rc7 2017-02-04 10:44:15 -08:00
bcma Revert "bcma: init serial console directly from ChipCommon code" 2017-01-17 14:23:44 +02:00
block xen-blkfront: correct maximum segment accounting 2017-01-23 13:27:42 -05:00
bluetooth Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-12-16 10:24:44 -08:00
bus cpu/hotplug: Cleanup state names 2016-12-25 10:47:44 +01:00
cdrom Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
char Merge 4.10-rc7 into char-misc-next 2017-02-06 09:39:13 +01:00
clk One fix for Samsung Exynos524x SoCs where recent IOMMU patches have 2017-01-21 18:46:45 -08:00
clocksource clocksource/exynos_mct: Clear interrupt when cpu is shut down 2017-01-17 10:08:38 +01:00
connector
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cpufreq Merge branches 'pm-sleep' and 'pm-cpufreq' 2017-01-27 00:08:59 +01:00
cpuidle Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2016-12-27 17:51:36 -08:00
dax libnvdimm for 4.10 2016-12-18 15:49:10 -08:00
dca
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devfreq PM / devfreq: exynos-bus: Fix the wrong return value 2017-01-03 00:21:45 +01:00
dio Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
dma dmaengine: pl330: fix double lock 2017-01-25 15:35:11 +05:30
dma-buf
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edac Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
eisa
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extcon extcon: palmas: Use dev_dbg macro for the debug messages 2017-01-25 15:03:54 +09:00
firewire
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firmware efi/fdt: Avoid FDT manipulation after ExitBootServices() 2017-02-01 21:17:49 +01:00
fmc
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fpga fpga zynq: Use the scatterlist interface 2017-02-10 15:20:44 +01:00
fsi drivers/fsi: add driver to device matches 2017-02-10 15:19:48 +01:00
gpio gpio: provide lockdep keys for nested/unnested irqchips 2017-01-19 09:57:20 +01:00
gpu Merge branch 'drm-fixes-4.10' of git://people.freedesktop.org/~agd5f/linux into drm-fixes 2017-02-03 09:10:08 +10:00
hid HID: cp2112: fix gpio-callback error handling 2017-01-31 12:59:33 +01:00
hsi
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hv hv_utils: implement Hyper-V PTP source 2017-02-10 15:40:19 +01:00
hwmon hwmon: (lm90) fix temp1_max_alarm attribute 2017-01-02 10:15:28 -08:00
hwspinlock
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hwtracing coresight: etm4x: Fix timestamp configuration when working from perf 2017-01-25 11:46:42 +01:00
i2c i2c: imx-lpi2c: add VLLS mode support 2017-01-26 00:24:23 +01:00
ide Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
idle Power management material for v4.10-rc1 2016-12-13 10:41:53 -08:00
iio iio: dht11: Use usleep_range instead of msleep for start signal 2017-01-22 13:35:40 +00:00
infiniband RDMA/cma: Fix unknown symbol when CONFIG_IPV6 is not enabled 2017-01-27 14:29:04 -05:00
input Input: synaptics-rmi4 - fix reversed conditions in enable/disable_irq_wake 2017-01-31 00:51:06 -08:00
iommu IOMMU Fixes for Linux v4.10-rc2 2017-01-06 10:49:36 -08:00
ipack
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irqchip Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-25 14:30:04 -08:00
isdn ISDN: eicon: silence misleading array-bounds warning 2017-01-27 11:27:34 -05:00
leds cpu/hotplug: Cleanup state names 2016-12-25 10:47:44 +01:00
lguest Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
lightnvm Char/Misc driver patches for 4.10-rc1 2016-12-13 12:11:01 -08:00
macintosh Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
mailbox ktime: Cleanup ktime_set() usage 2016-12-25 17:21:22 +01:00
mcb
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md md/r5cache: disable write back for degraded array 2017-01-24 11:26:06 -08:00
media media fixes for v4.10-rc6 2017-01-27 10:29:33 -08:00
memory memory: aemif: allow passing device lookup table as platform data 2017-01-19 12:42:25 +01:00
memstick drivers/memstick/core/memstick.c: avoid -Wnonnull warning 2017-01-24 16:26:14 -08:00
message Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
mfd - New Device Support 2016-12-19 08:16:26 -08:00
misc misc: panel: Abstract temporary backlight handling 2017-02-10 15:34:02 +01:00
mmc mmc: sdhci: Ignore unexpected CARD_INT interrupts 2017-01-31 11:26:49 +01:00
mtd mtd: nand: lpc32xx: fix invalid error handling of a requested irq 2017-01-04 20:50:18 +01:00
net Char/misc driver fixes for 4.10-rc7 2017-02-04 10:44:15 -08:00
nfc
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ntb ntb_transport: Remove unnecessary call to ntb_peer_spad_read 2016-12-23 16:11:07 -05:00
nubus Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
nvdimm libnvdimm, namespace: fix pmem namespace leak, delete when size set to zero 2017-01-13 09:50:33 -08:00
nvme nvme-fc: use blk_rq_nr_phys_segments 2017-01-26 17:49:14 +02:00
nvmem nvmem: core: Allow getting nvmem cell with a NULL cell id 2017-01-25 11:49:39 +01:00
of pci-v4.10-changes 2016-12-15 12:46:48 -08:00
oprofile Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
parisc Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
parport parisc, parport_gsc: Fixes for printk continuation lines 2017-01-28 21:54:21 +01:00
pci PCI/ASPM: Handle PCI-to-PCIe bridges as roots of PCIe hierarchies 2017-01-27 15:00:45 -06:00
pcmcia drivers/pcmcia/m32r_pcc.c: check return from add_pcc_socket 2016-12-12 18:55:06 -08:00
perf cpu/hotplug: Cleanup state names 2016-12-25 10:47:44 +01:00
phy SCSI misc on 20161213 2016-12-14 10:49:33 -08:00
pinctrl pinctrl: baytrail: Add missing spinlock usage in byt_gpio_irq_handler 2017-01-30 15:53:57 +01:00
platform platform/x86: ideapad-laptop: handle ACPI event 1 2017-01-22 12:47:06 +02:00
pnp Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
power ktime: Cleanup ktime_set() usage 2016-12-25 17:21:22 +01:00
powercap powercap / RAPL: Add Knights Mill CPUID 2016-11-30 23:41:33 +01:00
pps
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ps3
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ptp Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-12 19:56:15 -08:00
pwm pwm: Changes for v4.10-rc1 2016-12-15 11:45:13 -08:00
rapidio
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ras
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regulator regulator: Fixes for v4.10 2017-02-03 13:46:38 -08:00
remoteproc Revert "remoteproc: Merge table_ptr and cached_table pointers" 2016-12-30 03:26:31 -08:00
reset ARM: SoC driver updates for v4.10 2016-12-15 16:03:25 -08:00
rpmsg rpmsg: virtio_rpmsg_bus: fix channel creation 2016-12-30 03:12:11 -08:00
rtc rtc: jz4740: make the driver buildable as a module again 2017-01-26 23:03:21 +01:00
s390 virtio/s390: virtio: constify virtio_config_ops structures 2017-01-19 23:46:34 +02:00
sbus Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
scsi SCSI fixes on 20170203 2017-02-03 16:18:51 -08:00
sfi
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sh lib: radix-tree: check accounting of existing slot replacement users 2016-12-12 18:55:08 -08:00
sn
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soc soc: ti: wkup_m3_ipc: Fix error return code in wkup_m3_ipc_probe() 2017-01-12 13:37:49 -08:00
spi spi: Fixes for v4.10 2017-01-20 12:25:11 -08:00
spmi
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ssb
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staging staging: greybus: timesync: validate platform state callback 2017-01-25 11:36:59 +01:00
target target: support XCOPY requests without parameters 2017-01-10 08:41:30 -08:00
tc
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thermal Revert "thermal: thermal_hwmon: Convert to hwmon_device_register_with_info()" 2017-01-25 09:51:08 +08:00
thunderbolt Char/Misc driver patches for 4.10-rc1 2016-12-13 12:11:01 -08:00
tty sysrq: attach sysrq handler correctly for 32-bit kernel 2017-01-11 09:22:54 +01:00
uio uio-hv-generic: store physical addresses instead of virtual 2016-12-10 14:57:58 +01:00
usb USB-serial fixes for v4.10-rc7 2017-02-03 22:19:15 +01:00
uwb
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vfio vfio/spapr: Fix missing mutex unlock when creating a window 2017-02-01 09:48:34 -07:00
vhost vhost: fix initialization for vq->is_le 2017-02-03 23:38:57 +02:00
video fbdev: color map copying bounds checking 2017-01-24 16:26:14 -08:00
virt
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virtio Revert "vring: Force use of DMA API for ARM-based systems with legacy devices" 2017-02-03 23:38:50 +02:00
vlynq
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vme VME: restore bus_remove function causing incomplete module unload 2017-01-25 11:41:44 +01:00
w1 w1: ds2405: use module_w1_family to simplify the code 2017-02-10 15:32:53 +01:00
watchdog Watchdog updates for v4.10 2016-12-24 11:27:45 -08:00
xen Merge branch 'stable/for-linus-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb 2017-01-27 12:17:07 -08:00
zorro Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
Kconfig drivers/fsi: Add empty fsi bus definitions 2017-02-10 15:19:48 +01:00
Makefile drivers/fsi: Add empty fsi bus definitions 2017-02-10 15:19:48 +01:00