When Hyper-V host asks us to remove some util driver by closing the
appropriate channel there is no easy way to force the current file
descriptor holder to hang up but we can start to respond -EBADF to all
operations asking it to exit gracefully.

As we're setting hvt->mode from two separate contexts now we need to use
a proper locking.
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>

As a preparation to reusing outmsg_lock to protect test-and-set openrations
on 'mode' rename it the more general 'lock'.
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>

inmsg should be freed in case of on_msg() failure to avoid memory leak.
Preserve the error code from on_msg().
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>

Fix the write()'s argument in the daemon code.

Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When the handshake with daemon is complete, we should poll the channel since
during the handshake, we will not be processing any messages. This is a
potential bug if the host is waiting for a response from the guest.
I would like to thank Dexuan for pointing this out.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Force all channel messages to be delivered on CPU0. These messages are not
performance critical and are used during the setup and teardown of the
channel.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Hypervisor Top Level Functional Specification v3/4 says
that TSC page sequence value = -1(0xFFFFFFFF) is used to
indicate that TSC page no longer reliable source of reference
timer. Unfortunately, we found that Windows Hyper-V guest
side implementation uses sequence value = 0 to indicate
that Tsc page no longer valid. This is clearly visible
inside Windows 2012R2 ntoskrnl.exe HvlGetReferenceTime()
function dissassembly:

HvlGetReferenceTime proc near
                 xchg    ax, ax
loc_1401C3132:
                 mov     rax, cs:HvlpReferenceTscPage
                 mov     r9d, [rax]
                 test    r9d, r9d
                 jz      short loc_1401C3176
                 rdtsc
                 mov     rcx, cs:HvlpReferenceTscPage
                 shl     rdx, 20h
                 or      rdx, rax
                 mov     rax, [rcx+8]
                 mov     rcx, cs:HvlpReferenceTscPage
                 mov     r8, [rcx+10h]
                 mul     rdx
                 mov     rax, cs:HvlpReferenceTscPage
                 add     rdx, r8
                 mov     ecx, [rax]
                 cmp     ecx, r9d
                 jnz     short loc_1401C3132
                 jmp     short loc_1401C3184
loc_1401C3176:
                 mov     ecx, 40000020h
                 rdmsr
                 shl     rdx, 20h
                 or      rdx, rax
loc_1401C3184:
                 mov     rax, rdx
                 retn
HvlGetReferenceTime endp

This patch aligns Tsc page invalid sequence value with
Windows Hyper-V guest implementation which is more
compatible with both Hyper-V hypervisor and KVM hypervisor.
Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Haiyang Zhang <haiyangz@microsoft.com>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently we have two policies for deciding when to signal the host:
One based on the ring buffer state and the other based on what the
VMBUS client driver wants to do. Consider the case when the client
wants to explicitly control when to signal the host. In this case,
if the client were to defer signaling, we will not be able to signal
the host subsequently when the client does want to signal since the
ring buffer state will prevent the signaling. Implement logic to
have only one signaling policy in force for a given channel.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Tested-by: Haiyang Zhang <haiyangz@microsoft.com>
Cc: <stable@vger.kernel.org> # v4.2+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch makes 16GB GPUs work in Hyper-V VMs, since, for
compatibility reasons, the Hyper-V BIOS lists MMIO ranges in 2GB
chunks in its root bus's _CRS object.
Signed-off-by: Jake Oshins <jakeo@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

spinlock is unnecessary here.
mutex is enough.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

We want to simplify vmbus_onoffer_rescind() by not invoking
hv_process_channel_removal(NULL, ...).
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In the path vmbus_onoffer_rescind() -> vmbus_device_unregister()  ->
device_unregister() -> ... -> __device_release_driver(), we can see for a
device without a driver loaded: dev->driver is NULL, so
dev->bus->remove(dev), namely vmbus_remove(), isn't invoked.

As a result, vmbus_remove() -> hv_process_channel_removal() isn't invoked
and some cleanups(like sending a CHANNELMSG_RELID_RELEASED message to the
host) aren't done.

We can demo the issue this way:
1. rmmod hv_utils;
2. disable the Heartbeat Integration Service in Hyper-V Manager and lsvmbus
shows the device disappears.
3. re-enable the Heartbeat in Hyper-V Manager and modprobe hv_utils, but
lsvmbus shows the device can't appear again.
This is because, the host thinks the VM hasn't released the relid, so can't
re-offer the device to the VM.

We can fix the issue by moving hv_process_channel_removal()
from vmbus_close_internal() to vmbus_device_release(), since the latter is
always invoked on device_unregister(), whether or not the dev has a driver
loaded.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This fixes an incorrect assumption of channel state in the function.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

process_chn_event(), running in the tasklet, can race with
vmbus_close_internal() in the case of SMP guest, e.g., when the former is
accessing channel->inbound.ring_buffer, the latter could be freeing the
ring_buffer pages.

To resolve the race, we can serialize them by disabling the tasklet when
the latter is running here.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The irq we extract from ACPI is not used - we deliver hypervisor
interrupts on a special vector. Make the necessary adjustments.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The macro VMBUS_DEVICE() is unused; get rid of it.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Use uuid_le_cmp() for comparing GUIDs.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Consistently use uuid_le type in the Hyper-V driver code.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The Backup integration service on WS2012 has appearently trouble to
negotiate with a guest which does not support the provided util version.
Currently the VSS driver supports only version 5/0. A WS2012 offers only
version 1/x and 3/x, and vmbus_prep_negotiate_resp correctly returns an
empty icframe_vercnt/icmsg_vercnt. But the host ignores that and
continues to send ICMSGTYPE_NEGOTIATE messages. The result are weird
errors during boot and general misbehaviour.

Check the Windows version to work around the host bug, skip hv_vss_init
on WS2012 and older.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This defines the channel type for PCI front-ends in Hyper-V VMs.
Signed-off-by: Jake Oshins <jakeo@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch exposes the function that hv_vmbus.ko uses to make hypercalls.  This
is necessary for retargeting an interrupt when it is given a new affinity.

Since we are exporting this API, rename the API as it will be visible outside
the hv.c file.
Signed-off-by: Jake Oshins <jakeo@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch exposes the mapping between Linux CPU number and Hyper-V virtual
processor number.  This is necessary because the hypervisor needs to know which
virtual processors to target when making a mapping in the Interrupt Redirection
Table in the I/O MMU.
Signed-off-by: Jake Oshins <jakeo@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Before vmbus_connect() synic is setup per vcpu - this means
hypervisor receives writes at synic msr's and probably allocate
hypervisor resources per synic setup.

If vmbus_connect() failed for some reason it's neccessary to cleanup
synic setup by call hv_synic_cleanup() at each vcpu to get a chance
to free allocated resources by hypervisor per synic.

This patch does appropriate cleanup in case of vmbus_connect() failure.
Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Haiyang Zhang <haiyangz@microsoft.com>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Use memdup_user to handle OOM.

Fixes: 14b50f80 ('Drivers: hv: util: introduce hv_utils_transport abstraction')
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Catch allocation errors in hvutil_transport_send.

Fixes: 14b50f80 ('Drivers: hv: util: introduce hv_utils_transport abstraction')
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

HV_FCOPY is already used as identifier in syslog.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently some "Unspecified error 0x80004005" is reported on the Windows
side if something fails. Handle the ENOSPC case and return
ERROR_DISK_FULL, which allows at least Copy-VMFile to report a meaning
full error.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

All channel interrupts are bound to specific VCPUs in the guest
at the point channel is created. While currently, we invoke the
polling function on the correct CPU (the CPU to which the channel
is bound to) in some cases we may run the polling function in
a non-interrupt context. This  potentially can cause an issue as the
polling function can be interrupted by the channel callback function.
Fix the issue by running the polling function on the appropriate CPU
at interrupt level. Additional details of the issue being addressed by
this patch are given below:

Currently hv_fcopy_onchannelcallback is called from interrupts and also
via the ->write function of hv_utils. Since the used global variables to
maintain state are not thread safe the state can get out of sync.
This affects the variable state as well as the channel inbound buffer.

As suggested by KY adjust hv_poll_channel to always run the given
callback on the cpu which the channel is bound to. This avoids the need
for locking because all the util services are single threaded and only
one transaction is active at any given point in time.

Additionally, remove the context variable, they will always be the same as
recv_channel.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Util services such as KVP and FCOPY need assistance from daemon's running
in user space. Increase the timeout so we don't prematurely terminate
the transaction in the kernel. Host sets up a 60 second timeout for
all util driver transactions. The host will retry the transaction if it
times out. Set the guest timeout at 30 seconds.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

We were getting build warning about unused variable "tsc_msr" and
"va_tsc" while building for i386 allmodconfig.
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add support to find string-similar symbols.  When option --sim SYM is
specified, checkkconfigsymbols.py will print at most 10 symbols defined
in Kconfig that are string similar to SYM in the following format:
    Similar symbols: $COMMA_SEPARATED_LIST_OF_SYMBOLS

Note, if no similar symbols are found it is indicated as follows:
    Similar symbols: no similar symbols found

Since the implemented functionality is also useful when searching the
entire source or when diffing two commits, a list of similar symbols is
printed unconditionally with the other data.  In order to make the
output more readable, the format now looks as follows:

    $UNDEFINED_SYMBOL
    Referencing files: $COMMA_SEPARATED_LIST_OF_FILES
    Similar symbols: $COMMA_SEPARATED_LIST_OF_SYMBOLS
    [Optional with '--find']
    Commits changing symbol:
        - $COMMIT_1_HASH ("$COMMIT_1_MESSAGE")
        - $COMMIT_2_HASH ("$COMMIT_2_MESSAGE")
            or
        - no commit found
Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Distribute the parsing of source and Kconfig files on all available
cores to speed up processing.
Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Jan Stancek reported that I wrecked things for him by fixing things for
Vladimir :/

His report was due to an UNINTERRUPTIBLE wait getting -EINTR, which
should not be possible, however my previous patch made this possible by
unconditionally checking signal_pending().

We cannot use current->state as was done previously, because the
instruction after the store to that variable it can be changed.  We must
instead pass the initial state along and use that.

Fixes: 68985633 ("sched/wait: Fix signal handling in bit wait helpers")
Reported-by: Jan Stancek <jstancek@redhat.com>
Reported-by: Chris Mason <clm@fb.com>
Tested-by: Jan Stancek <jstancek@redhat.com>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com>
Tested-by: Chris Mason <clm@fb.com>
Reviewed-by: Paul Turner <pjt@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: tglx@linutronix.de
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: hpa@zytor.com
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull NFS client bugfix from Trond Myklebust:
 "SUNRPC: Fix a NFSv4.1 callback channel regression"

* tag 'nfs-for-4.4-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  SUNRPC: Fix callback channel

Pull timer fixlets from Thomas Gleixner:
 "Two trivial fixes which add missing header fileas and forward
  declarations so the code will compile even when the magic include
  chains are different"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gic-v3: Add missing include for barrier.h
  irqchip/gic-v3: Add missing struct device_node declaration

Pull timer fix from Thomas Gleixner:
 "A single fix to unbreak a clocksource driver which has more than 32bit
  counter width"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource: Mmio: remove artificial 32bit limitation

Pull fpga driver fixes from Greg KH:
 "Only two small fpga driver fixes here, both have been in linux-next
  for a while, and resolve some reported issues"

* tag 'char-misc-4.4-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  fpga manager: Fix firmware resource leak on error
  fpga manager: remove label

Pull staging driver fixes from Greg KH:
 "Here are a few staging and IIO driver fixes for 4.4-rc5.

  All of them resolve reported problems and have been in linux-next for
  a while.  Nothing major here, just small fixes where needed"

* tag 'staging-4.4-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: lustre: echo_copy.._lsm() dereferences userland pointers directly
  iio: adc: spmi-vadc: add missing of_node_put
  iio: fix some warning messages
  iio: light: apds9960: correct ->last_busy count
  iio: lidar: return -EINVAL on invalid signal
  staging: iio: dummy: complete IIO events delivery to userspace

Pull USB driver fixes from Greg KH:
 "Here are a number of small USB fixes for 4.4-rc5.  All of them have
  been in linux-next.  The majority are gadget and phy issues, with a
  few new quirks and device ids added as well"

* tag 'usb-4.4-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (32 commits)
  USB: add quirk for devices with broken LPM
  xhci: fix usb2 resume timing and races.
  usb: musb: fail with error when no DMA controller set
  usb: gadget: uvc: fix permissions of configfs attributes
  usb: musb: core: Fix pm runtime for deferred probe
  usb: phy: msm: fix a possible NULL dereference
  USB: host: ohci-at91: fix a crash in ohci_hcd_at91_overcurrent_irq
  usb: Quiet down false peer failure messages
  usb: xhci: fix config fail of FS hub behind a HS hub with MTT
  xhci: Fix memory leak in xhci_pme_acpi_rtd3_enable()
  usb: Use the USB_SS_MULT() macro to decode burst multiplier for log message
  USB: whci-hcd: add check for dma mapping error
  usb: core : hub: Fix BOS 'NULL pointer' kernel panic
  USB: quirks: Apply ALWAYS_POLL to all ELAN devices
  usb-storage: Fix scsi-sd failure "Invalid field in cdb" for USB adapter JMicron
  USB: quirks: Fix another ELAN touchscreen
  usb: dwc3: gadget: don't prestart interrupt endpoints
  USB: serial: Another Infineon flash loader USB ID
  USB: cdc_acm: Ignore Infineon Flash Loader utility
  USB: cp210x: Remove CP2110 ID from compatibility list
  ...