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>

The vmbus devices are NOT child devices; rename vmbus_child_device_create
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>

Replace struct hv_guid with the uuid type already defined in Linux.
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>

Get rid of an unused function in connection.c
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NAbhishek Kane <v-abkane@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Cleanup hyperv_vmbus.h.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NAbhishek Kane <v-abkane@microsoft.com>
Signed-off-by: NHank Janssen <hjanssen@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Move the contents of vmbus_private.h to vmbus_hyperv.h.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NAbhishek Kane <v-abkane@microsoft.com>
Signed-off-by: NHank Janssen <hjanssen@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Move the contents of ring_buffer.h to hyperv_vmbus.h.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NAbhishek Kane <v-abkane@microsoft.com>
Signed-off-by: NHank Janssen <hjanssen@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Move the content of hv.h to hyperv_vmbus.h.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NAbhishek Kane <v-abkane@microsoft.com>
Signed-off-by: NHank Janssen <hjanssen@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Include the contents of hv_api.h in hyperv_vmbus.h.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NAbhishek Kane <v-abkane@microsoft.com>
Signed-off-by: NHank Janssen <hjanssen@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Create a common header file to build the vmbus driver.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NAbhishek Kane <v-abkane@microsoft.com>
Signed-off-by: NHank Janssen <hjanssen@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Include the newly introduced msidef.h to solve the build issues.
Signed-off-by: NXiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Moving irqchip_in_kernel() from ioapic.h to irq.h.
Signed-off-by: NXiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Moving irq ack notification logic as common, and make
it shared with ia64 side.
Signed-off-by: NXiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>