Implement the protocol for tearing down the monitor state established with
the host.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Tested-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

KVP/VSS/FCOPY drivers work in fully serialized mode: we wait till userspace
daemon registers, wait for a message from the host, send this message to the
daemon, get the reply, send it back to host, wait for another message.
Introduce enum hvutil_device_state to represend this state in all 3 drivers.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Tested-by: NAlex Ng <alexng@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Move poll_channel() to hyperv_vmbus.h and make it inline and rename it to hv_poll_channel() so it can be reused
in other hv_util modules.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Tested-by: NAlex Ng <alexng@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

These declarations are internal to hv_util module and hv_fcopy_* declarations
already reside there.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Tested-by: NAlex Ng <alexng@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since the 2 fucntions can safely run in vmbus_connection.work_queue without
hang, we don't need to schedule new work items into the per-channel workqueue.

Actally we can even remove the per-channel workqueue now -- we'll do it
in the next patch.
Signed-off-by: NDexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

A work item in vmbus_connection.work_queue can sleep, waiting for a new
host message (usually it is some kind of "completion" message). Currently
the new message will be handled in the same workqueue, but since work items
in the workqueue is serialized, we actually have no chance to handle
the new message if the current work item is sleeping -- as as result, the
current work item will hang forever.

K. Y. has posted the below fix to resolve the issue:
Drivers: hv: vmbus: Perform device register in the per-channel work element

Actually we can simplify the fix by directly running non-blocking message
handlers in the dispatch tasklet (inspired by K. Y.).

This patch is the fundamental change. The following 2 patches will simplify
the message offering and rescind-offering handling a lot.
Signed-off-by: NDexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

HV_CRASH_CTL_CRASH_NOTIFY is a 64 bit number.  Depending on the usage context,
the value may be truncated. This patch is in response from the following
email from Wu Fengguang <fengguang.wu@intel.com>:

    From: Wu Fengguang <fengguang.wu@intel.com>
    Subject:  [char-misc:char-misc-testing 25/45] drivers/hv/vmbus_drv.c:67:9: sparse:
              constant 0x8000000000000000 is so big it is unsigned long

    tree:   git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git char-misc-testing
    head:   b3de8e37
    commit: 96c1d058 [25/45] Drivers: hv: vmbus: Add support for VMBus panic notifier handler
    reproduce:
      # apt-get install sparse
      git checkout 96c1d058
      make ARCH=x86_64 allmodconfig
      make C=1 CF=-D__CHECK_ENDIAN__

    sparse warnings: (new ones prefixed by >>)

    drivers/hv/vmbus_drv.c:67:9: sparse: constant 0x8000000000000000 is so big it is unsigned long
    ...
Signed-off-by: NNick Meier <nmeier@microsoft.com>
Reported-by: NWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch is a continuation of the rescind handling cleanup work. We cannot
block in the global message handling work context especially if we are blocking
waiting for the host to wake us up. I would like to thank
Dexuan Cui <decui@microsoft.com> for observing this problem.

The current char-next branch is broken and this patch fixes
the bug.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Hyper-V allows a guest to notify the Hyper-V host that a panic
condition occured.  This notification can include up to five 64
bit values.  These 64 bit values are written into crash MSRs.
Once the data has been written into the crash MSRs, the host is
then notified by writing into a Crash Control MSR.  On the Hyper-V
host, the panic notification data is captured in the Windows Event
log as a 18590 event.

Crash MSRs are defined in appendix H of the Hypervisor Top Level
Functional Specification.  At the time of this patch, v4.0 is the
current functional spec.  The URL for the v4.0 document is:

http://download.microsoft.com/download/A/B/4/AB43A34E-BDD0-4FA6-BDEF-79EEF16E880B/Hypervisor Top Level Functional Specification v4.0.docx
Signed-off-by: NNick Meier <nmeier@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Newly introduced clockevent devices made it impossible to unload hv_vmbus
module as clockevents_config_and_register() takes additional reverence to
the module. To make it possible again we do the following:
- avoid setting dev->owner for clockevent devices;
- implement hv_synic_clockevents_cleanup() doing clockevents_unbind_device();
- call it from vmbus_exit().

In theory hv_synic_clockevents_cleanup() can be merged with hv_synic_cleanup(),
however, we call hv_synic_cleanup() from smp_call_function_single() and this
doesn't work for clockevents_unbind_device() as it does such call on its own. I
opted for a separate function.
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 destroy hv_vmbus_con on module shutdown, otherwise the following
crash is sometimes observed:

[   76.569845] hv_vmbus: Hyper-V Host Build:9600-6.3-17-0.17039; Vmbus version:3.0
[   82.598859] BUG: unable to handle kernel paging request at ffffffffa0003480
[   82.599287] IP: [<ffffffffa0003480>] 0xffffffffa0003480
[   82.599287] PGD 1f34067 PUD 1f35063 PMD 3f72d067 PTE 0
[   82.599287] Oops: 0010 [#1] SMP
[   82.599287] Modules linked in: [last unloaded: hv_vmbus]
[   82.599287] CPU: 0 PID: 26 Comm: kworker/0:1 Not tainted 3.19.0-rc5_bug923184+ #488
[   82.599287] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v1.0 11/26/2012
[   82.599287] Workqueue: hv_vmbus_con 0xffffffffa0003480
[   82.599287] task: ffff88007b6ddfa0 ti: ffff88007f8f8000 task.ti: ffff88007f8f8000
[   82.599287] RIP: 0010:[<ffffffffa0003480>]  [<ffffffffa0003480>] 0xffffffffa0003480
[   82.599287] RSP: 0018:ffff88007f8fbe00  EFLAGS: 00010202
...

To avoid memory leaks we need to free monitor_pages and int_page for
vmbus_connection. Implement vmbus_disconnect() function by separating cleanup
path from vmbus_connect().

As we use hv_vmbus_con to release channels (see free_channel() in channel_mgmt.c)
we need to make sure the work was done before we remove the queue, do that with
drain_workqueue(). We also need to avoid handling messages  which can (potentially)
create new channels, so set vmbus_connection.conn_state = DISCONNECTED at the very
beginning of vmbus_exit() and check for that in vmbus_onmessage_work().
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>

Implement a clockevent device based on the timer support available on
Hyper-V.
In this version of the patch I have addressed Jason's review comments.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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 <decui@microsoft.com>.

I would like to thank Sitsofe Wheeler <sitsofe@yahoo.com>
for reporting the issue and helping in debuggging.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reported-by: NSitsofe Wheeler <sitsofe@yahoo.com>
Cc: <stable@vger.kernel.org>
Tested-by: NSitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The uuid structure could be managed as a const in several places.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently the mapping of the relID to channel is done under the protection of a
single spin lock. Starting with ws2012, each channel is bound to a specific VCPU
in the guest. Use this binding to eliminate the spin lock by setting up
per-cpu state for mapping relId to the channel.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Implement the file copy service for Linux guests on Hyper-V. This permits the
host to copy a file (over VMBUS) into the guest. This facility is part of
"guest integration services" supported on the Windows platform.
Here is a link that provides additional details on this functionality:

http://technet.microsoft.com/en-us/library/dn464282.aspx

In V1 version of the patch I have addressed comments from
Olaf Hering <olaf@aepfle.de> and Dan Carpenter <dan.carpenter@oracle.com>

In V2 version of this patch I did some minor cleanup (making some globals
static). In V4 version of the patch I have addressed all of Olaf's
most recent set of comments/concerns.

In V5 version of the patch I had addressed Greg's most recent comments.
I would like to thank Greg for suggesting that I use misc device; it has
significantly simplified the code.

In V6 version of the patch I have cleaned up error message based on Olaf's
comments. I have also rebased the patch based on the current tip.

In this version of the patch, I have addressed the latest comments from Greg.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The current channel code is using scatterlist abstraction to pass data to the
ringbuffer API on the send path. This causes unnecessary translations
between virtual and physical addresses. Fix this.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

It's no longer needed, and the struct hv_ring_buffer_debug_info
structure shouldn't be "global" so move it to the local .h file instead.
Tested-by: N"K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

monitor_pages was a void pointer, containing an unknown number of arrays that
we just "knew" were a child and parent array of a specific size.  Instead of
that implicit knowledge, let's make them a real pointer, allowing us to have
type safety, and a semblance of sane addressing schemes.
Tested-by: N"K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We currently allocate synic structures in hv_sync_init(), but there's no way for
the driver to know about the allocation failure and it may continue to use the
uninitialized pointers. Solve this by introducing helpers for allocating and
freeing and doing the allocation before the on_each_cpu() call in
vmbus_bus_init().

Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Capture the host build information so it can be presented along with the
negotiated vmbus version information.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Implement flow management on the send side. When the sender is blocked, the reader
can potentially signal the sender to indicate there is now room to send.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Now that we can potentially take vmbus interrupts on any CPU, make the
tasklets per-CPU.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Now that we have implemented a per-connection signaling mechanism, get rid
of the global signaling state. For hosts that don't support per-connection
signaling handle, we have moved the global state to be a per-channel state.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

On win8 (ws2012), incoming vmbus interrupt load can be spread across all
available VCPUs in the guest. On a per-channel basis, the interrupts can
be bound to specific CPUs. The Linux notion of cpu ID may be different
from that of the hypervisor's. Setup a mapping structure.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The current code has a global handle for supporting signaling of the host
from guest. Make this a per-channel attribute as on some versions of the
host we can signal on per-channel handle.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In preparation for supporting a per-connection signaling mechanism,
change the signature of vmbus_set_event(). This change is also
needed to implement other aspects of the signaling optimization.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In preparation for implementing a per-connection signaling framework,
change the signature of the function hv_signal_event(). The current
code uses a global handle for signaling the host.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This function is no longer used; get rid of it.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The host has already implemented the "read" side optimizations.
Leverage that to optimize "write" side signaling.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Implement functions that will support read-side signaling optimization.
By having the reader indicate the start of the "read" operation and the
"end" of the read operation we can more efficiently handle the signaling
protocol: while the read is in progress, there is no need for the "writer"
to signal the "reader" as new items are put on the read queue.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The current guest ID string in use in vmbus driver does not conform
to the MSFT guidelines on guest ID. MSFT currently does not specify
Linux specific guidelines. MSFT however has plans to publish Linux
specific guidelines. This implementation conforms to the yet unpublished
Linux specific guidelines for guest ID. This implementation also broadly
conforms to the current guidelines as well.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Cc: Bjørn Mork <bjorn@mork.no>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The hex constant chosen for HV_LINUX_GUEST_ID_HI was offensive, update to use
the decimal equivalent instead.
Reported-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Acked-by: NJeff Garzik <jgarzik@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This function returns negative error codes, but because the type is u16
they get truncated into positive numbers.  It doesn't look like the
callers care, but we should fix it anyway as a cleanup.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The current code arbirarily limited the number of CPUs the guest could have.
Change that so that we can support the maximum number of CPUs the guest can
support. While we use NR_CPUS to size the per-cpu state all we are allocating
based on NR_CPUS are the  pointers to per-cpu state that will be allocatted in
the context of the initializing CPU. This patch triggers a checkpatch warning
for the usage of NR_CPU and since all we are allocating a couple of pointers
per CPU, it should be ok.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

It turns out that the vmbus driver can be made unloadable. Make it
unloadable.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This also removed the unused function hv_dump_ring_info().

Cc: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

After many years wandering the desert, it is finally time for the
Microsoft HyperV code to move out of the staging directory.  Or at least
the core hyperv bus code, and the utility driver, the rest still have
some review to get through by the various subsystem maintainers.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>

The vmbus devices are NOT child devices; rename vmbus_child_device_unregister
to reflect this.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The vmbus devices are NOT child devices; rename vmbus_child_device_register
to reflect this.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>