linux-stable.git/drivers/hv, branch v3.16.35

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

Drivers: hv: vmbus: Cleanup vmbus_establish_gpadl()

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

commit 72c6b71c245dac8f371167d97ef471b367d0b66b upstream.

Eliminate the call to BUG_ON() by waiting for the host to respond. We are
trying to reclaim the ownership of memory that was given to the host and so
we will have to wait until the host responds.

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

Drivers: hv: vmbus: Cleanup vmbus_close_internal()

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

commit 98d731bb064a9d1817a6ca9bf8b97051334a7cfe upstream.

Eliminate calls to BUG_ON() in vmbus_close_internal().
We have chosen to potentially leak memory, than crash the guest
in case of failures.

In this version of the patch I have addressed comments from
Dan Carpenter (dan.carpenter@oracle.com).

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

Drivers: hv: vmbus: Cleanup vmbus_teardown_gpadl()

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

commit 66be653083057358724d56d817e870e53fb81ca7 upstream.

Eliminate calls to BUG_ON() by properly handling errors. In cases where
rollback is possible, we will return the appropriate error to have the
calling code decide how to rollback state. In the case where we are
transferring ownership of the guest physical pages to the host,
we will wait for the host to respond.

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

Drivers: hv: vmbus: Cleanup vmbus_post_msg()

2014-10-30T16:40:12+00:00

commit fdeebcc62279119dbeafbc1a2e39e773839025fd upstream.

Posting messages to the host can fail because of transient resource
related failures. Correctly deal with these failures and increase the
number of attempts to post the message before giving up.

In this version of the patch, I have normalized the error code to
Linux error code.

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