The current code unconditionally sends an IPI. If we are running on the
correct CPU and are in interrupt level, we don't need an IPI.
Make this adjustment.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

ENOBUFS is a more approrpiate error code to be returned
when the hypervisor cannot post the message because of
insufficient buffers. Make the adjustment.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Don't enable auto-eoi if the hypervisor recommends otherwise. This will
enable vAPIC functionality if available.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Allow driver to get debug information about state of the ring.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Minor changes to align hyper-v vmbus include files with current
linux kernel style.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This table is immutable and should be const.
Cleanup indentation and whitespace for this as well.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

hv_ringbuffer_read cleanup.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Several spelling errors in comments
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Don't initialize variables that are then set a few lines later.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

No need for empty return at end of void function
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The change to reschedule tasklet if more data arrives in ring buffer
can cause performance regression if host timing is such that the
next response happens in small window.

Go back to a modified version of the original looping behavior.
If the race occurs in a small time, then loop. But if the tasklet
has been running for a long interval due to flood, then reschedule
the tasklet to allow migration to ksoftirqd.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When we close a channel that has been rescinded, we will leak memory since
vmbus_teardown_gpadl() returns an error. Fix this so that we can properly
cleanup the memory allocated to the ring buffers.

Fixes: ccb61f8a ("Drivers: hv: vmbus: Fix a rescind handling bug")
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If we cannot allocate memory for the channel, free the relid
associated with the channel.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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

Fixes: 3716a49a ("hv_utils: implement Hyper-V PTP source")
Signed-off-by: NDexuan Cui <decui@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Waiting for release_event in all three drivers introduced issues on release
as on_reset() hook is not always called. E.g. if the device was never
opened we will never get the completion.

Move the waiting code to hvutil_transport_destroy() and make sure it is
only called when the device is open. hvt->lock serialization should
guarantee the absence of races.

Fixes: 5a66fecb ("Drivers: hv: util: kvp: Fix a rescind processing issue")
Fixes: 20951c75 ("Drivers: hv: util: Fcopy: Fix a rescind processing issue")
Fixes: d77044d1 ("Drivers: hv: util: Backup: Fix a rescind processing issue")
Reported-by: NDexuan Cui <decui@microsoft.com>
Tested-by: NDexuan Cui <decui@microsoft.com>
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

With the recent introduction of per-channel tasklet, we need to update
the way we handle the 3 concurrency issues:

1. hv_process_channel_removal -> percpu_channel_deq vs.
   vmbus_chan_sched -> list_for_each_entry(..., percpu_list);

2. vmbus_process_offer -> percpu_channel_enq/deq vs. vmbus_chan_sched.

3. vmbus_close_internal vs. the per-channel tasklet vmbus_on_event;

The first 2 issues can be handled by Stephen's recent patch
"vmbus: use rcu for per-cpu channel list", and the third issue
can be handled by calling tasklet_disable in vmbus_close_internal here.

We don't need the original hv_event_tasklet_disable/enable since we
now use per-channel tasklet instead of the previous per-CPU tasklet,
and actually we must remove them due to the side effect now:
vmbus_process_offer -> hv_event_tasklet_enable -> tasklet_schedule will
start the per-channel callback prematurely, cauing NULL dereferencing
(the channel may haven't been properly configured to run the callback yet).

Fixes: 631e63a9 ("vmbus: change to per channel tasklet")
Signed-off-by: NDexuan Cui <decui@microsoft.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Tested-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The per-cpu channel list is now referred to in the interrupt
routine. This is mostly safe since the host will not normally generate
an interrupt when channel is being deleted but if it did then there
would be a use after free problem.

To solve, this use RCU protection on ther per-cpu list.

Fixes: 631e63a9 ("vmbus: change to per channel tasklet")
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

To use Hyper-V TSC page clocksource from vDSO we need to make tsc_pg
available. Implement hv_get_tsc_page() and add CONFIG_HYPERV_TSCPAGE to
make #ifdef-s simple.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: devel@linuxdriverproject.org
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: virtualization@lists.linux-foundation.org
Link: http://lkml.kernel.org/r/20170303132142.25595-2-vkuznets@redhat.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Fix typos and add the following to the scripts/spelling.txt:

  disble||disable
  disbled||disabled

I kept the TSL2563_INT_DISBLED in /drivers/iio/light/tsl2563.c
untouched.  The macro is not referenced at all, but this commit is
touching only comment blocks just in case.

Link: http://lkml.kernel.org/r/1481573103-11329-20-git-send-email-yamada.masahiro@socionext.comSigned-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is mostly just a refactoring of previous functions
(get_pkt_next_raw, put_pkt_raw and commit_rd_index) to make it easier
to use for other drivers and NAPI.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/task_stack.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Takes less clock cycles to check for ring wrap and subtract than to
do a modulus instruction.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Functions that just query state of ring buffer can have parameters
marked const.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In order to implement NAPI in netvsc, the driver needs access to
control host interrupt mask.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

All current usage of vmbus write uses the acquire_lock flag, therefore
having it be optional is unnecessary. This also fixes a sparse warning
since sparse doesn't like when a function has conditional locking.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Make the event handling tasklet per channel rather than per-cpu.
This allows for better fairness when getting lots of data on the same
cpu.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The hv_context structure had several arrays which were per-cpu
and was allocating small structures (tasklet_struct). Instead use
a single per-cpu array.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since sendpacket no longer uses kickq argument remove it.
Remove it no longer used xmit_more in sendpacket in netvsc as well.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The flag to cause notification of host is unused after
commit a01a291a282f7c2e ("Drivers: hv: vmbus: Base host signaling
strictly on the ring state"). Therefore remove it from the ring
buffer internal API.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use standard kernel operations for find first set bit to traverse
the channel bit array. This has added benefit of speeding up
lookup on 64 bit and because it uses find first set instruction.
Signed-off-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix a typo.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Log the negotiated IC versions.
Signed-off-by: NAlex Ng <alexng@messages.microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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: 3da0401b ("Drivers: hv: utils: Fix the mapping between host
version and protocol to use")
Reported-by: NRolf Neugebauer <rolf.neugebauer@docker.com>
Signed-off-by: NAlex Ng <alexng@messages.microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Coverity scan gives a warning when there is fall through in a switch
without a comment. This fall through is intentional as ol_waitevent needs
to be completed to unblock hv_mem_hot_add() allowing it to process next
requests regardless of the result of if we were able to online this block.
Reported-by: NStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We need to cleanup the hypercall page before doing kexec/kdump or the new
kernel may crash if it tries to use it. Reuse the now-empty hv_cleanup
function renaming it to hyperv_cleanup and moving to the arch specific
code.

Fixes: 8730046c ("Drivers: hv vmbus: Move Hypercall page setup out of common code")
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

do_settimeofday() is deprecated, use do_settimeofday64() instead.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: NJohn Stultz <john.stultz@linaro.org>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit a389fcfd ("Drivers: hv: vmbus: Fix signaling logic in
hv_need_to_signal_on_read()")
added the proper mb(), but removed the test "prev_write_sz < pending_sz"
when making the signal decision.

As a result, the guest can signal the host unnecessarily,
and then the host can throttle the guest because the host
thinks the guest is buggy or malicious; finally the user
running stress test can perceive intermittent freeze of
the guest.

This patch brings back the test, and properly handles the
in-place consumption APIs used by NetVSC (see get_next_pkt_raw(),
put_pkt_raw() and commit_rd_index()).

Fixes: a389fcfd ("Drivers: hv: vmbus: Fix signaling logic in
hv_need_to_signal_on_read()")
Signed-off-by: NDexuan Cui <decui@microsoft.com>
Reported-by: NRolf Neugebauer <rolf.neugebauer@docker.com>
Tested-by: NRolf Neugebauer <rolf.neugebauer@docker.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Get rid of all unused definitions.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>