linux-stable.git/drivers/hv, branch v3.16.40

hv: do not lose pending heartbeat vmbus packets

2017-02-23T03:54:20+00:00

commit 407a3aee6ee2d2cb46d9ba3fc380bc29f35d020c upstream.

The host keeps sending heartbeat packets independent of the
guest responding to them.  Even though we respond to the heartbeat messages at
interrupt level, we can have situations where there maybe multiple heartbeat
messages pending that have not been responded to. For instance this occurs when the
VM is paused and the host continues to send the heartbeat messages.
Address this issue by draining and responding to all
the heartbeat messages that maybe pending.

Signed-off-by: Long Li 
Signed-off-by: K. Y. Srinivasan 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Ben Hutchings

random: add interrupt callback to VMBus IRQ handler

2016-11-20T01:16:40+00:00

commit 4b44f2d18a330565227a7348844493c59366171e upstream.

The Hyper-V Linux Integration Services use the VMBus implementation for
communication with the Hypervisor. VMBus registers its own interrupt
handler that completely bypasses the common Linux interrupt handling.
This implies that the interrupt entropy collector is not triggered.

This patch adds the interrupt entropy collection callback into the VMBus
interrupt handler function.

Signed-off-by: Stephan Mueller 
Signed-off-by: Stephan Mueller 
Signed-off-by: Theodore Ts'o 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

Drivers: hv: vmbus: Fix signaling logic in hv_need_to_signal_on_read()

2016-06-15T20:29:29+00:00

commit 1db488d12894f1936360779d6ab2aede3dd7f06a upstream.

On the consumer side, we have interrupt driven flow management of the
producer. It is sufficient to base the signaling decision on the
amount of space that is available to write after the read is complete.
The current code samples the previous available space and uses this
in making the signaling decision. This state can be stale and is
unnecessary. Since the state can be stale, we end up not signaling
the host (when we should) and this can result in a hang. Fix this
problem by removing the unnecessary check. I would like to thank
Arseney Romanenko  for pointing out this issue.

Also, issue a full memory barrier before making the signaling descision
to correctly deal with potential reordering of the write (read index)
followed by the read of pending_sz.

Signed-off-by: K. Y. Srinivasan 
Tested-by: Dexuan Cui 
Signed-off-by: Greg Kroah-Hartman 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

Drivers: hv_vmbus: Fix signal to host condition

2016-06-15T20:29:29+00:00

commit a5cca686ce0ef4909deaee4ed46dd991e3a9ece4 upstream.

Fixes a bug where previously hv_ringbuffer_read would pass in the old
number of bytes available to read instead of the expected old read index
when calculating when to signal to the host that the ringbuffer is empty.
Since the previous write size is already saved, also changes the
hv_need_to_signal_on_read to use the previously read value rather than
recalculating it.

Signed-off-by: Christopher Oo 
Signed-off-by: K. Y. Srinivasan 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Ben Hutchings

Drivers: hv: vmbus: prevent cpu offlining on newer hypervisors

2016-04-11T10:01:20+00:00

commit e513229b4c386e6c9f66298c13fde92f73e6e1ac upstream.

When an SMP Hyper-V guest is running on top of 2012R2 Server and secondary
cpus are sent offline (with echo 0 > /sys/devices/system/cpu/cpu$cpu/online)
the system freeze is observed. This happens due to the fact that on newer
hypervisors (Win8, WS2012R2, ...) vmbus channel handlers are distributed
across all cpus (see init_vp_index() function in drivers/hv/channel_mgmt.c)
and on cpu offlining nobody reassigns them to CPU0. Prevent cpu offlining
when vmbus is loaded until the issue is fixed host-side.

This patch also disables hibernation but it is OK as it is also broken (MCE
error is hit on resume). Suspend still works.

Tested with WS2008R2 and WS2012R2.

Signed-off-by: Vitaly Kuznetsov 
Signed-off-by: K. Y. Srinivasan 
Signed-off-by: Greg Kroah-Hartman 
Cc: Chas Williams <3chas3@gmail.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques

Drivers: hv: vmbus: Don't wait after requesting offers

2015-05-05T10:09:38+00:00

commit 73cffdb65e679b98893f484063462c045adcf212 upstream.

Don't wait after sending request for offers to the host. This wait is
unnecessary and simply adds 5 seconds to the boot time.

Signed-off-by: K. Y. Srinivasan 
Signed-off-by: Greg Kroah-Hartman 
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques

Drivers: hv: vmbus: Fix a bug in the error path in vmbus_open()

2015-05-04T15:06:36+00:00

commit 40384e4bbeb9f2651fe9bffc0062d9f31ef625bf upstream.

Correctly rollback state if the failure occurs after we have handed over
the ownership of the buffer to the host.

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

Drivers: hv: vmbus: Fix a race condition when unregistering a device

2015-01-05T13:48:39+00:00

commit 04a258c162a85c0f4ae56be67634dc43c9a4fa9b upstream.

When build with Debug the following crash is sometimes observed:
Call Trace:
 [] string+0x40/0x100
 [] vsnprintf+0x218/0x5e0
 [] ? trace_hardirqs_off+0xd/0x10
 [] vscnprintf+0x11/0x30
 [] vprintk+0xd0/0x5c0
 [] ? vmbus_process_rescind_offer+0x0/0x110 [hv_vmbus]
 [] printk+0x41/0x45
 [] vmbus_device_unregister+0x2c/0x40 [hv_vmbus]
 [] vmbus_process_rescind_offer+0x2b/0x110 [hv_vmbus]
...

This happens due to the following race: between 'if (channel->device_obj)' check
in vmbus_process_rescind_offer() and pr_debug() in vmbus_device_unregister() the
device can disappear. Fix the issue by taking an additional reference to the
device before proceeding to vmbus_device_unregister().

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

Drivers: hv: vmbus: Cleanup hv_post_message()

2014-10-30T16:40:13+00:00

commit b29ef3546aecb253a5552b198cef23750d56e1e4 upstream.

Minimize failures in this function by pre-allocating the buffer
for posting messages. The hypercall for posting the message can fail
for a number of reasons:

        1. Transient resource related issues
        2. Buffer alignment
        3. Buffer cannot span a page boundry

We address issues 2 and 3 by preallocating a per-cpu page for the buffer.
Transient resource related failures are handled by retrying by the callers
of this function.

This patch is based on the investigation
done by Dexuan Cui .

I would like to thank Sitsofe Wheeler 
for reporting the issue and helping in debuggging.

Signed-off-by: K. Y. Srinivasan 
Reported-by: Sitsofe Wheeler 
Tested-by: Sitsofe Wheeler 
Signed-off-by: Greg Kroah-Hartman

Drivers: hv: vmbus: Fix a bug in vmbus_open()

2014-10-30T16:40:13+00:00

commit 45d727cee9e200f5b351528b9fb063b69cf702c8 upstream.

Fix a bug in vmbus_open() and properly propagate the error. I would
like to thank Dexuan Cui  for identifying the
issue.

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