[PATCH v1 0/1] misc: IBM Virtual Management Channel Driver

[PATCH v1 0/1] misc: IBM Virtual Management Channel Driver

[Bryant G. Ly]

Steven Royer had previously attempted to upstream this
driver two years ago, but never got the chance to address
the concerns from Greg Kroah-Hartman.

The thread with the initial upstream is:
https://lkml.org/lkml/2016/2/16/918

I have addressed the following:
- Documentation
- Use of dev_dbg instead of pr_dbg
- Change to misc class
- Fixed memory barrier usages
- Addressed styling, checkpatch, renaming of functions
- General fixes to the driver to make it more inline with
  existing upstream drivers.

Bryant G. Ly (1):
  misc: IBM Virtual Management Channel Driver

 Documentation/ioctl/ioctl-number.txt  |    1 +
 Documentation/misc-devices/ibmvmc.txt |  161 +++
 MAINTAINERS                           |    6 +
 arch/powerpc/include/asm/hvcall.h     |    1 +
 drivers/misc/Kconfig                  |    9 +
 drivers/misc/Makefile                 |    1 +
 drivers/misc/ibmvmc.c                 | 2413 +++++++++++++++++++++++++++++++++
 drivers/misc/ibmvmc.h                 |  215 +++
 8 files changed, 2807 insertions(+)
 create mode 100644 Documentation/misc-devices/ibmvmc.txt
 create mode 100644 drivers/misc/ibmvmc.c
 create mode 100644 drivers/misc/ibmvmc.h

-- 
2.7.2

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[PATCH v1 0/1] misc: IBM Virtual Management Channel Driver

[Bryant G. Ly]

Steven Royer had previously attempted to upstream this
driver two years ago, but never got the chance to address
the concerns from Greg Kroah-Hartman.

The thread with the initial upstream is:
https://lkml.org/lkml/2016/2/16/918

I have addressed the following:
- Documentation
- Use of dev_dbg instead of pr_dbg
- Change to misc class
- Fixed memory barrier usages
- Addressed styling, checkpatch, renaming of functions
- General fixes to the driver to make it more inline with
  existing upstream drivers.

Bryant G. Ly (1):
  misc: IBM Virtual Management Channel Driver

 Documentation/ioctl/ioctl-number.txt  |    1 +
 Documentation/misc-devices/ibmvmc.txt |  161 +++
 MAINTAINERS                           |    6 +
 arch/powerpc/include/asm/hvcall.h     |    1 +
 drivers/misc/Kconfig                  |    9 +
 drivers/misc/Makefile                 |    1 +
 drivers/misc/ibmvmc.c                 | 2413 +++++++++++++++++++++++++++++++++
 drivers/misc/ibmvmc.h                 |  215 +++
 8 files changed, 2807 insertions(+)
 create mode 100644 Documentation/misc-devices/ibmvmc.txt
 create mode 100644 drivers/misc/ibmvmc.c
 create mode 100644 drivers/misc/ibmvmc.h

-- 
2.7.2

[PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Bryant G. Ly]

This driver is a logical device which provides an
interface between the hypervisor and a management
partition.

This driver is to be used for the POWER Virtual
Management Channel Virtual Adapter on the PowerVM
platform. It provides both request/response and
async message support through the /dev/ibmvmc node.

Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Reviewed-by: Steven Royer <seroyer@linux.vnet.ibm.com>
Reviewed-by: Adam Reznechek <adreznec@linux.vnet.ibm.com>
Tested-by: Taylor Jakobson <tjakobs@us.ibm.com>
Tested-by: Brad Warrum <bwarrum@us.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
---
 Documentation/ioctl/ioctl-number.txt  |    1 +
 Documentation/misc-devices/ibmvmc.txt |  161 +++
 MAINTAINERS                           |    6 +
 arch/powerpc/include/asm/hvcall.h     |    1 +
 drivers/misc/Kconfig                  |   14 +
 drivers/misc/Makefile                 |    1 +
 drivers/misc/ibmvmc.c                 | 2415 +++++++++++++++++++++++++++++++++
 drivers/misc/ibmvmc.h                 |  209 +++
 8 files changed, 2808 insertions(+)
 create mode 100644 Documentation/misc-devices/ibmvmc.txt
 create mode 100644 drivers/misc/ibmvmc.c
 create mode 100644 drivers/misc/ibmvmc.h

diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
index 84bb74d..9851cee 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -329,6 +329,7 @@ Code  Seq#(hex)	Include File		Comments
 0xCA	80-BF	uapi/scsi/cxlflash_ioctl.h
 0xCB	00-1F	CBM serial IEC bus	in development:
 					<mailto:michael.klein@puffin.lb.shuttle.de>
+0xCC	00-0F	drivers/misc/ibmvmc.h    pseries VMC driver
 0xCD	01	linux/reiserfs_fs.h
 0xCF	02	fs/cifs/ioctl.c
 0xDB	00-0F	drivers/char/mwave/mwavepub.h
diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-devices/ibmvmc.txt
new file mode 100644
index 0000000..bae1064
--- /dev/null
+++ b/Documentation/misc-devices/ibmvmc.txt
@@ -0,0 +1,161 @@
+Kernel Driver ibmvmc
+====================
+
+Authors:
+	Dave Engebretsen <engebret@us.ibm.com>
+	Adam Reznechek <adreznec@linux.vnet.ibm.com>
+	Steven Royer <seroyer@linux.vnet.ibm.com>
+	Bryant G. Ly <bryantly@linux.vnet.ibm.com>
+
+Description
+===========
+
+The Virtual Management Channel (VMC) is a logical device which provides an
+interface between the hypervisor and a management partition. This
+management partition is intended to provide an alternative to HMC-based
+system management. In the management partition, a Novalink application
+exists which enables a system administrator to configure the system’s
+partitioning characteristics via a command line interface (CLI) or
+Representational State Transfer Application (REST). You can also manage the
+server by using PowerVC or other OpenStack solution. Support for
+conventional HMC management of the system may still be provided on a
+system; however, when an HMC is attached to the system, the VMC
+interface is disabled by the hypervisor.
+
+NovaLink runs on a Linux logical partition on a POWER8 or newer processor-
+based server that is virtualized by PowerVM. System configuration,
+maintenance, and control functions which traditionally require an HMC can
+be implemented in the Novalink using a combination of HMC to hypervisor
+interfaces and existing operating system methods. This tool provides a
+subset of the functions implemented by the HMC and enables basic partition
+configuration. The set of HMC to hypervisor messages supported by the
+Novalink component are passed to the hypervisor over a VMC interface, which
+is defined below.
+
+Virtual Management Channel (VMC)
+A logical device, called the virtual management channel (VMC), is defined
+for communicating between the Novalink application and the hypervisor.
+This device, similar to a VSCSI server device, is presented to a designated
+management partition as a virtual device and is only presented when the
+system is not HMC managed.
+This communication device borrows aspects from both VSCSI and ILLAN devices
+and is implemented using the CRQ and the RDMA interfaces. A three-way
+handshake is defined that must take place to establish that both the
+hypervisor and management partition sides of the channel are running prior
+to sending/receiving any of the protocol messages.
+This driver also utilizes Transport Event CRQs. CRQ messages that are sent
+when the hypervisor detects one of the peer partitions has abnormally
+terminated, or one side has called H_FREE_CRQ to close their CRQ.
+Two new classes of CRQ messages are introduced for the VMC device. VMC
+Administrative messages are used for each partition using the VMC to
+communicate capabilities to their partner. HMC Interface messages are used
+for the actual flow of HMC messages between the management partition and
+the hypervisor. As most HMC messages far exceed the size of a CRQ bugger,
+a virtual DMA (RMDA) of the HMC message data is done prior to each HMC
+Interface CRQ message. Only the management partition drives RDMA
+operations; hypervisors never directly causes the movement of message data.
+
+Example Management Partition VMC Driver Interface
+=================================================
+This section provides an example for the Novalink implementation where a
+device driver is used to interface to the VMC device. This driver
+consists of a new device, for example /dev/lparvmc, which provides
+interfaces to open, close, read, write, and perform ioctl’s against the
+VMC device.
+
+VMC Interface Initialization
+The device driver is responsible for initializing the VMC when the driver
+is loaded. It first creates and initializes the CRQ. Next, an exchange of
+VMC capabilities is performed to indicate the code version and number of
+resources available in both the management partition and the hypervisor.
+Finally, the hypervisor requests that the management partition create an
+initial pool of VMC buffers, one buffer for each possible HMC connection,
+which will be used for Novalink session initialization. Prior to completion
+of this initialization sequence, the device returns EBUSY to open() calls.
+EIO is returned for all open() failures.
+
+Management Partition		Hypervisor
+		CRQ INIT
+---------------------------------------->
+	   CRQ INIT COMPLETE
+<----------------------------------------
+	      CAPABILITIES
+---------------------------------------->
+	 CAPABILITIES RESPONSE
+<----------------------------------------
+      ADD BUFFER (MHC IDX=0,1,..)	  _
+<----------------------------------------  |
+	  ADD BUFFER RESPONSE		   | - Perform # HMCs Iterations
+----------------------------------------> -
+
+VMC Interface Open
+After the basic VMC channel has been initialized, an HMC session level
+connection can be established. The application layer performs an open() to
+the VMC device and executes an ioctl() against it, indicating the HMC ID
+(32 bytes of data) for this session. If the VMC device is in an invalid
+state, EIO will be returned for the ioctl(). The device driver creates a
+new HMC session value (ranging from 1 to 255) and HMC index value (starting
+at index 0 and potentially ranging to 254 in future releases) for this HMC
+ID. The driver then does an RDMA of the HMC ID to the hypervisor, and then
+sends an Interface Open message to the hypervisor to establish the session
+over the VMC. After the hypervisor receives this information, it sends Add
+Buffer messages to the management partition to seed an initial pool of
+buffers for the new HMC connection. Finally, the hypervisor sends an
+Interface Open Response message, to indicate that it is ready for normal
+runtime messaging. The following illustrates this VMC flow:
+
+Management Partition             Hypervisor
+	      RDMA HMC ID
+---------------------------------------->
+	    Interface Open
+---------------------------------------->
+	      Add Buffer		  _
+<----------------------------------------  |
+	  Add Buffer Response		   | - Perform N Iterations
+----------------------------------------> -
+	Interface Open Response
+<----------------------------------------
+
+VMC Interface Runtime
+During normal runtime, the Novalink application and the hypervisor
+exchange HMC messages via the Signal VMC message and RDMA operations. When
+sending data to the hypervisor, the Novalink application performs a
+write() to the VMC device, and the driver RDMA’s the data to the hypervisor
+and then sends a Signal Message. If a write() is attempted before VMC
+device buffers have been made available by the hypervisor, or no buffers
+are currently available, EBUSY is returned in response to the write(). A
+write() will return EIO for all other errors, such as an invalid device
+state. When the hypervisor sends a message to the Novalink, the data is
+put into a VMC buffer and an Signal Message is sent to the VMC driver in
+the management partition. The driver RDMA’s the buffer into the partition
+and passes the data up to the appropriate Novalink application via a
+read() to the VMC device. The read() request blocks if there is no buffer
+available to read. The Novalink application may use select() to wait for
+the VMC device to become ready with data to read.
+
+Management Partition             Hypervisor
+		MSG RDMA
+---------------------------------------->
+		SIGNAL MSG
+---------------------------------------->
+		SIGNAL MSG
+<----------------------------------------
+		MSG RDMA
+<----------------------------------------
+
+VMC Interface Close
+HMC session level connections are closed by the management partition when
+the application layer performs a close() against the device. This action
+results in an Interface Close message flowing to the hypervisor, which
+causes the session to be terminated. The device driver must free any
+storage allocated for buffers for this HMC connection.
+
+Management Partition             Hypervisor
+	     INTERFACE CLOSE
+---------------------------------------->
+        INTERFACE CLOSE RESPONSE
+<----------------------------------------
+
+For more information on the documentation for CRQ Messages, VMC Messages,
+HMC interface Buffers, and signal messages please refer to the Linux on
+Power Architecture Platform Reference. Section F.
diff --git a/MAINTAINERS b/MAINTAINERS
index c7182d2..79969f9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6721,6 +6721,12 @@ L:	linux-scsi@vger.kernel.org
 S:	Supported
 F:	drivers/scsi/ibmvscsi/ibmvfc*
 
+IBM Power Virtual Management Channel Driver
+M:	Bryant G. Ly <bryantly@linux.vnet.ibm.com>
+M:	Steven Royer <seroyer@linux.vnet.ibm.com>
+S:	Supported
+F:	drivers/misc/ibmvmc.*
+
 IBM Power Virtual SCSI Device Drivers
 M:	Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
 L:	linux-scsi@vger.kernel.org
diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
index 2e2ddda..662c834 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -279,6 +279,7 @@
 #define H_GET_MPP_X		0x314
 #define H_SET_MODE		0x31C
 #define H_CLEAR_HPT		0x358
+#define H_REQUEST_VMC		0x360
 #define H_RESIZE_HPT_PREPARE	0x36C
 #define H_RESIZE_HPT_COMMIT	0x370
 #define H_REGISTER_PROC_TBL	0x37C
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 5d71300..3726eac 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -113,6 +113,20 @@ config IBM_ASM
 	  for information on the specific driver level and support statement
 	  for your IBM server.
 
+config IBMVMC
+	tristate "IBM Virtual Management Channel support"
+	depends on PPC_PSERIES
+	help
+	  This is the IBM POWER Virtual Management Channel
+
+	  This driver is to be used for the POWER Virtual
+	  Management Channel virtual adapter on the PowerVM
+	  platform. It provides both request/response and
+	  async message support through the /dev/ibmvmc node.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ibmvmc.
+
 config PHANTOM
 	tristate "Sensable PHANToM (PCI)"
 	depends on PCI
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 20be70c..af22bbc 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -4,6 +4,7 @@
 #
 
 obj-$(CONFIG_IBM_ASM)		+= ibmasm/
+obj-$(CONFIG_IBMVMC)		+= ibmvmc.o
 obj-$(CONFIG_AD525X_DPOT)	+= ad525x_dpot.o
 obj-$(CONFIG_AD525X_DPOT_I2C)	+= ad525x_dpot-i2c.o
 obj-$(CONFIG_AD525X_DPOT_SPI)	+= ad525x_dpot-spi.o
diff --git a/drivers/misc/ibmvmc.c b/drivers/misc/ibmvmc.c
new file mode 100644
index 0000000..ae9cea3
--- /dev/null
+++ b/drivers/misc/ibmvmc.c
@@ -0,0 +1,2415 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * IBM Power Systems Virtual Management Channel Support.
+ *
+ * Copyright (c) 2004, 2018 IBM Corp.
+ *   Dave Engebretsen engebret@us.ibm.com
+ *   Steven Royer seroyer@linux.vnet.ibm.com
+ *   Adam Reznechek adreznec@linux.vnet.ibm.com
+ *   Bryant G. Ly <bryantly@linux.vnet.ibm.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/major.h>
+#include <linux/string.h>
+#include <linux/fcntl.h>
+#include <linux/slab.h>
+#include <linux/poll.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/percpu.h>
+#include <linux/delay.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+#include <linux/miscdevice.h>
+#include <linux/sched/signal.h>
+
+#include <asm/byteorder.h>
+#include <asm/irq.h>
+#include <asm/vio.h>
+
+#include "ibmvmc.h"
+
+#define IBMVMC_DRIVER_VERSION "1.0"
+
+/*
+ * Static global variables
+ */
+static DECLARE_WAIT_QUEUE_HEAD(ibmvmc_read_wait);
+
+static const char ibmvmc_driver_name[] = "ibmvmc";
+
+static struct ibmvmc_struct ibmvmc;
+static struct ibmvmc_hmc hmcs[MAX_HMCS];
+static struct crq_server_adapter ibmvmc_adapter;
+
+static int ibmvmc_max_buf_pool_size = DEFAULT_BUF_POOL_SIZE;
+static int ibmvmc_max_hmcs = DEFAULT_HMCS;
+static int ibmvmc_max_mtu = DEFAULT_MTU;
+
+static inline long h_copy_rdma(s64 length, u64 sliobn, u64 slioba,
+			       u64 dliobn, u64 dlioba)
+{
+	long rc = 0;
+
+	/* Ensure all writes to source memory are visible before hcall */
+	dma_wmb();
+	pr_debug("ibmvmc: h_copy_rdma(0x%llx, 0x%llx, 0x%llx, 0x%llx, 0x%llx\n",
+		 length, sliobn, slioba, dliobn, dlioba);
+	rc = plpar_hcall_norets(H_COPY_RDMA, length, sliobn, slioba,
+				dliobn, dlioba);
+	pr_debug("ibmvmc: h_copy_rdma rc = 0x%lx\n", rc);
+
+	return rc;
+}
+
+static inline void h_free_crq(uint32_t unit_address)
+{
+	long rc = 0;
+
+	do {
+		if (H_IS_LONG_BUSY(rc))
+			msleep(get_longbusy_msecs(rc));
+
+		rc = plpar_hcall_norets(H_FREE_CRQ, unit_address);
+	} while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
+}
+
+/**
+ * h_request_vmc: - request a hypervisor virtual management channel device
+ * @vmc_index: drc index of the vmc device created
+ *
+ * Requests the hypervisor create a new virtual management channel device,
+ * allowing this partition to send hypervisor virtualization control
+ * commands.
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static inline long h_request_vmc(u32 *vmc_index)
+{
+	long rc = 0;
+	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
+
+	do {
+		if (H_IS_LONG_BUSY(rc))
+			msleep(get_longbusy_msecs(rc));
+
+		/* Call to request the VMC device from phyp */
+		rc = plpar_hcall(H_REQUEST_VMC, retbuf);
+		pr_debug("ibmvmc: %s rc = 0x%lx\n", __func__, rc);
+		*vmc_index = retbuf[0];
+	} while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
+
+	return rc;
+}
+
+/* routines for managing a command/response queue */
+/**
+ * ibmvmc_handle_event: - Interrupt handler for crq events
+ * @irq:        number of irq to handle, not used
+ * @dev_instance: crq_server_adapter that received interrupt
+ *
+ * Disables interrupts and schedules ibmvmc_task
+ *
+ * Always returns IRQ_HANDLED
+ */
+static irqreturn_t ibmvmc_handle_event(int irq, void *dev_instance)
+{
+	struct crq_server_adapter *adapter =
+		(struct crq_server_adapter *)dev_instance;
+
+	vio_disable_interrupts(to_vio_dev(adapter->dev));
+	tasklet_schedule(&adapter->work_task);
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * ibmvmc_release_crq_queue - Release CRQ Queue
+ *
+ * @adapter:	crq_server_adapter struct
+ *
+ * Return:
+ *	0 - Success
+ *	Non-Zero - Failure
+ */
+static void ibmvmc_release_crq_queue(struct crq_server_adapter *adapter)
+{
+	struct vio_dev *vdev = to_vio_dev(adapter->dev);
+	struct crq_queue *queue = &adapter->queue;
+
+	free_irq(vdev->irq, (void *)adapter);
+	tasklet_kill(&adapter->work_task);
+
+	if (adapter->reset_task)
+		kthread_stop(adapter->reset_task);
+
+	h_free_crq(vdev->unit_address);
+	dma_unmap_single(adapter->dev,
+			 queue->msg_token,
+			 queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);
+	free_page((unsigned long)queue->msgs);
+}
+
+/**
+ * ibmvmc_reset_crq_queue - Reset CRQ Queue
+ *
+ * @adapter:	crq_server_adapter struct
+ *
+ * This function calls h_free_crq and then calls H_REG_CRQ and does all the
+ * bookkeeping to get us back to where we can communicate.
+ *
+ * Return:
+ *	0 - Success
+ *	Non-Zero - Failure
+ */
+static int ibmvmc_reset_crq_queue(struct crq_server_adapter *adapter)
+{
+	struct vio_dev *vdev = to_vio_dev(adapter->dev);
+	struct crq_queue *queue = &adapter->queue;
+	int rc = 0;
+
+	/* Close the CRQ */
+	h_free_crq(vdev->unit_address);
+
+	/* Clean out the queue */
+	memset(queue->msgs, 0x00, PAGE_SIZE);
+	queue->cur = 0;
+
+	/* And re-open it again */
+	rc = plpar_hcall_norets(H_REG_CRQ,
+				vdev->unit_address,
+				queue->msg_token, PAGE_SIZE);
+	if (rc == 2)
+		/* Adapter is good, but other end is not ready */
+		dev_warn(adapter->dev, "Partner adapter not ready\n");
+	else if (rc != 0)
+		dev_err(adapter->dev, "couldn't register crq--rc 0x%x\n", rc);
+
+	return rc;
+}
+
+/**
+ * crq_queue_next_crq: - Returns the next entry in message queue
+ * @queue:      crq_queue to use
+ *
+ * Returns pointer to next entry in queue, or NULL if there are no new
+ * entried in the CRQ.
+ */
+static struct ibmvmc_crq_msg *crq_queue_next_crq(struct crq_queue *queue)
+{
+	struct ibmvmc_crq_msg *crq;
+	unsigned long flags;
+
+	spin_lock_irqsave(&queue->lock, flags);
+	crq = &queue->msgs[queue->cur];
+	if (crq->valid & 0x80) {
+		if (++queue->cur == queue->size)
+			queue->cur = 0;
+
+		/* Ensure the read of the valid bit occurs before reading any
+		 * other bits of the CRQ entry
+		 */
+		dma_rmb();
+	} else {
+		crq = NULL;
+	}
+
+	spin_unlock_irqrestore(&queue->lock, flags);
+
+	return crq;
+}
+
+/**
+ * ibmvmc_send_crq - Send CRQ
+ *
+ * @adapter:	crq_server_adapter struct
+ * @word1:	Word1 Data field
+ * @word2:	Word2 Data field
+ *
+ * Return:
+ *	0 - Success
+ *	Non-Zero - Failure
+ */
+static long ibmvmc_send_crq(struct crq_server_adapter *adapter,
+			    u64 word1, u64 word2)
+{
+	struct vio_dev *vdev = to_vio_dev(adapter->dev);
+	long rc;
+
+	dev_dbg(adapter->dev, "(0x%x, 0x%016llx, 0x%016llx)\n",
+		vdev->unit_address, word1, word2);
+
+	/*
+	 * Ensure the command buffer is flushed to memory before handing it
+	 * over to the other side to prevent it from fetching any stale data.
+	 */
+	dma_wmb();
+	rc = plpar_hcall_norets(H_SEND_CRQ, vdev->unit_address, word1, word2);
+	dev_dbg(adapter->dev, "rc = 0x%lx\n", rc);
+
+	return rc;
+}
+
+/**
+ * alloc_dma_buffer - Create DMA Buffer
+ *
+ * @vdev:	vio_dev struct
+ * @size:	Size field
+ * @dma_handle:	DMA address field
+ *
+ * Allocates memory for the command queue and maps remote memory into an
+ * ioba.
+ *
+ * Returns a pointer to the buffer
+ */
+static void *alloc_dma_buffer(struct vio_dev *vdev, size_t size,
+			      dma_addr_t *dma_handle)
+{
+	/* allocate memory */
+	void *buffer = kzalloc(size, GFP_KERNEL);
+
+	if (!buffer) {
+		*dma_handle = 0;
+		return NULL;
+	}
+
+	/* DMA map */
+	*dma_handle = dma_map_single(&vdev->dev, buffer, size,
+				     DMA_BIDIRECTIONAL);
+
+	if (dma_mapping_error(&vdev->dev, *dma_handle)) {
+		*dma_handle = 0;
+		kzfree(buffer);
+		return NULL;
+	}
+
+	return buffer;
+}
+
+/**
+ * free_dma_buffer - Free DMA Buffer
+ *
+ * @vdev:	vio_dev struct
+ * @size:	Size field
+ * @vaddr:	Address field
+ * @dma_handle:	DMA address field
+ *
+ * Releases memory for a command queue and unmaps mapped remote memory.
+ */
+static void free_dma_buffer(struct vio_dev *vdev, size_t size, void *vaddr,
+			    dma_addr_t dma_handle)
+{
+	/* DMA unmap */
+	dma_unmap_single(&vdev->dev, dma_handle, size, DMA_BIDIRECTIONAL);
+
+	/* deallocate memory */
+	kzfree(vaddr);
+}
+
+/**
+ * ibmvmc_get_valid_hmc_buffer - Retrieve Valid HMC Buffer
+ *
+ * @hmc_index:	HMC Index Field
+ *
+ * Return:
+ *	Pointer to ibmvmc_buffer
+ */
+static struct ibmvmc_buffer *ibmvmc_get_valid_hmc_buffer(u8 hmc_index)
+{
+	struct ibmvmc_buffer *buffer;
+	struct ibmvmc_buffer *ret_buf = NULL;
+	unsigned long i;
+
+	if (hmc_index > ibmvmc.max_hmc_index)
+		return NULL;
+
+	buffer = hmcs[hmc_index].buffer;
+
+	for (i = 0; i < ibmvmc_max_buf_pool_size; i++) {
+		if (buffer[i].valid && buffer[i].free &&
+		    buffer[i].owner == VMC_BUF_OWNER_ALPHA) {
+			buffer[i].free = 0;
+			ret_buf = &buffer[i];
+			break;
+		}
+	}
+
+	return ret_buf;
+}
+
+/**
+ * ibmvmc_get_free_hmc_buffer - Get Free HMC Buffer
+ *
+ * @adapter:	crq_server_adapter struct
+ * @hmc_index:	Hmc Index field
+ *
+ * Return:
+ *	Pointer to ibmvmc_buffer
+ */
+static struct ibmvmc_buffer *ibmvmc_get_free_hmc_buffer(struct crq_server_adapter *adapter,
+							u8 hmc_index)
+{
+	struct ibmvmc_buffer *buffer;
+	struct ibmvmc_buffer *ret_buf = NULL;
+	unsigned long i;
+
+	if (hmc_index > ibmvmc.max_hmc_index) {
+		dev_info(adapter->dev, "get_free_hmc_buffer: invalid hmc_index=0x%x\n",
+			 hmc_index);
+		return NULL;
+	}
+
+	buffer = hmcs[hmc_index].buffer;
+
+	for (i = 0; i < ibmvmc_max_buf_pool_size; i++) {
+		if (buffer[i].free &&
+		    buffer[i].owner == VMC_BUF_OWNER_ALPHA) {
+			buffer[i].free = 0;
+			ret_buf = &buffer[i];
+			break;
+		}
+	}
+
+	return ret_buf;
+}
+
+/**
+ * ibmvmc_free_hmc_buffer - Free an HMC Buffer
+ *
+ * @hmc:	ibmvmc_hmc struct
+ * @buffer:	ibmvmc_buffer struct
+ *
+ */
+static void ibmvmc_free_hmc_buffer(struct ibmvmc_hmc *hmc,
+				   struct ibmvmc_buffer *buffer)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&hmc->lock, flags);
+	buffer->free = 1;
+	spin_unlock_irqrestore(&hmc->lock, flags);
+}
+
+/**
+ * ibmvmc_count_hmc_buffers - Count HMC Buffers
+ *
+ * @hmc_index:	HMC Index field
+ * @valid:	Valid number of buffers field
+ * @free:	Free number of buffers field
+ *
+ */
+static void ibmvmc_count_hmc_buffers(u8 hmc_index, unsigned int *valid,
+				     unsigned int *free)
+{
+	struct ibmvmc_buffer *buffer;
+	unsigned long i;
+	unsigned long flags;
+
+	if (hmc_index > ibmvmc.max_hmc_index)
+		return;
+
+	if (!valid || !free)
+		return;
+
+	*valid = 0; *free = 0;
+
+	buffer = hmcs[hmc_index].buffer;
+	spin_lock_irqsave(&hmcs[hmc_index].lock, flags);
+
+	for (i = 0; i < ibmvmc_max_buf_pool_size; i++) {
+		if (buffer[i].valid) {
+			*valid = *valid + 1;
+			if (buffer[i].free)
+				*free = *free + 1;
+		}
+	}
+
+	spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+}
+
+/**
+ * ibmvmc_get_free_hmc - Get Free HMC
+ *
+ * Return:
+ *	Pointer to an available HMC Connection
+ *	Null otherwise
+ */
+static struct ibmvmc_hmc *ibmvmc_get_free_hmc(void)
+{
+	unsigned long i;
+	unsigned long flags;
+
+	/*
+	 * Find an available HMC connection.
+	 */
+	for (i = 0; i <= ibmvmc.max_hmc_index; i++) {
+		spin_lock_irqsave(&hmcs[i].lock, flags);
+		if (hmcs[i].state == ibmhmc_state_free) {
+			hmcs[i].index = i;
+			hmcs[i].state = ibmhmc_state_initial;
+			spin_unlock_irqrestore(&hmcs[i].lock, flags);
+			return &hmcs[i];
+		}
+		spin_unlock_irqrestore(&hmcs[i].lock, flags);
+	}
+
+	return NULL;
+}
+
+/**
+ * ibmvmc_return_hmc - Return an HMC Connection
+ *
+ * @hmc:		ibmvmc_hmc struct
+ * @release_readers:	Number of readers connected to session
+ *
+ * This function releases the HMC connections back into the pool.
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static int ibmvmc_return_hmc(struct ibmvmc_hmc *hmc, bool release_readers)
+{
+	struct ibmvmc_buffer *buffer;
+	struct crq_server_adapter *adapter;
+	struct vio_dev *vdev;
+	unsigned long i;
+	unsigned long flags;
+
+	if (!hmc || !hmc->adapter)
+		return -EIO;
+
+	if (release_readers) {
+		if (hmc->file_session) {
+			struct ibmvmc_file_session *session = hmc->file_session;
+
+			session->valid = 0;
+			wake_up_interruptible(&ibmvmc_read_wait);
+		}
+	}
+
+	adapter = hmc->adapter;
+	vdev = to_vio_dev(adapter->dev);
+
+	spin_lock_irqsave(&hmc->lock, flags);
+	hmc->index = 0;
+	hmc->state = ibmhmc_state_free;
+	hmc->queue_head = 0;
+	hmc->queue_tail = 0;
+	buffer = hmc->buffer;
+	for (i = 0; i < ibmvmc_max_buf_pool_size; i++) {
+		if (buffer[i].valid) {
+			free_dma_buffer(vdev,
+					ibmvmc.max_mtu,
+					buffer[i].real_addr_local,
+					buffer[i].dma_addr_local);
+			dev_dbg(adapter->dev, "Forgot buffer id 0x%lx\n", i);
+		}
+		memset(&buffer[i], 0, sizeof(struct ibmvmc_buffer));
+
+		hmc->queue_outbound_msgs[i] = VMC_INVALID_BUFFER_ID;
+	}
+
+	spin_unlock_irqrestore(&hmc->lock, flags);
+
+	return 0;
+}
+
+/**
+ * ibmvmc_send_open - Interface Open
+ * @buffer: Pointer to ibmvmc_buffer struct
+ * @hmc: Pointer to ibmvmc_hmc struct
+ *
+ * This command is sent by the management partition as the result of a
+ * management partition device request. It causes the hypervisor to
+ * prepare a set of data buffers for the Novalink connection indicated HMC idx.
+ * A unique HMC Idx would be used if multiple management applications running
+ * concurrently were desired. Before responding to this command, the
+ * hypervisor must provide the management partition with at least one of these
+ * new buffers via the Add Buffer. This indicates whether the messages are
+ * inbound or outbound from the hypervisor.
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static int ibmvmc_send_open(struct ibmvmc_buffer *buffer,
+			    struct ibmvmc_hmc *hmc)
+{
+	struct ibmvmc_crq_msg crq_msg;
+	struct crq_server_adapter *adapter;
+	__be64 *crq_as_u64 = (__be64 *)&crq_msg;
+	int rc = 0;
+
+	if (!hmc || !hmc->adapter)
+		return -EIO;
+
+	adapter = hmc->adapter;
+
+	dev_dbg(adapter->dev, "send_open: 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
+		(unsigned long)buffer->size, (unsigned long)adapter->liobn,
+		(unsigned long)buffer->dma_addr_local,
+		(unsigned long)adapter->riobn,
+		(unsigned long)buffer->dma_addr_remote);
+
+	rc = h_copy_rdma(buffer->size,
+			 adapter->liobn,
+			 buffer->dma_addr_local,
+			 adapter->riobn,
+			 buffer->dma_addr_remote);
+	if (rc) {
+		dev_err(adapter->dev, "Error: In send_open, h_copy_rdma rc 0x%x\n",
+			rc);
+		return -EIO;
+	}
+
+	hmc->state = ibmhmc_state_opening;
+
+	crq_msg.valid = 0x80;
+	crq_msg.type = VMC_MSG_OPEN;
+	crq_msg.status = 0;
+	crq_msg.var1.rsvd = 0;
+	crq_msg.hmc_session = hmc->session;
+	crq_msg.hmc_index = hmc->index;
+	crq_msg.var2.buffer_id = cpu_to_be16(buffer->id);
+	crq_msg.rsvd = 0;
+	crq_msg.var3.rsvd = 0;
+
+	ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+			be64_to_cpu(crq_as_u64[1]));
+
+	return rc;
+}
+
+/**
+ * ibmvmc_send_close - Interface Close
+ * @hmc: Pointer to ibmvmc_hmc struct
+ *
+ * This command is sent by the management partition to terminate an Novalink to
+ * hypervisor connection. When this command is sent, the management
+ * partition has quiesced all I/O operations to all buffers associated with
+ * this Novalink connection, and has freed any storage for these buffers.
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static int ibmvmc_send_close(struct ibmvmc_hmc *hmc)
+{
+	struct ibmvmc_crq_msg crq_msg;
+	struct crq_server_adapter *adapter;
+	__be64 *crq_as_u64 = (__be64 *)&crq_msg;
+	int rc = 0;
+
+	if (!hmc || !hmc->adapter)
+		return -EIO;
+
+	adapter = hmc->adapter;
+
+	dev_info(adapter->dev, "CRQ send: close\n");
+
+	crq_msg.valid = 0x80;
+	crq_msg.type = VMC_MSG_CLOSE;
+	crq_msg.status = 0;
+	crq_msg.var1.rsvd = 0;
+	crq_msg.hmc_session = hmc->session;
+	crq_msg.hmc_index = hmc->index;
+	crq_msg.var2.rsvd = 0;
+	crq_msg.rsvd = 0;
+	crq_msg.var3.rsvd = 0;
+
+	ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+			be64_to_cpu(crq_as_u64[1]));
+
+	return rc;
+}
+
+/**
+ * ibmvmc_send_capabilities - Send VMC Capabilities
+ *
+ * @adapter:	crq_server_adapter struct
+ *
+ * The capabilities message is an administrative message sent after the CRQ
+ * initialization sequence of messages and is used to exchange VMC capabilities
+ * between the management partition and the hypervisor. The management
+ * partition must send this message and the hypervisor must respond with VMC
+ * capabilities Response message before HMC interface message can begin. Any
+ * HMC interface messages received before the exchange of capabilities has
+ * complete are dropped.
+ *
+ * Return:
+ *	0 - Success
+ */
+static int ibmvmc_send_capabilities(struct crq_server_adapter *adapter)
+{
+	struct ibmvmc_admin_crq_msg crq_msg;
+	__be64 *crq_as_u64 = (__be64 *)&crq_msg;
+
+	dev_dbg(adapter->dev, "ibmvmc: CRQ send: capabilities\n");
+	crq_msg.valid = 0x80;
+	crq_msg.type = VMC_MSG_CAP;
+	crq_msg.status = 0;
+	crq_msg.rsvd[0] = 0;
+	crq_msg.rsvd[1] = 0;
+	crq_msg.max_hmc = ibmvmc_max_hmcs;
+	crq_msg.max_mtu = cpu_to_be32(ibmvmc_max_mtu);
+	crq_msg.pool_size = cpu_to_be16(ibmvmc_max_buf_pool_size);
+	crq_msg.crq_size = cpu_to_be16(adapter->queue.size);
+	crq_msg.version = cpu_to_be16(IBMVMC_PROTOCOL_VERSION);
+
+	ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+			be64_to_cpu(crq_as_u64[1]));
+
+	ibmvmc.state = ibmvmc_state_capabilities;
+
+	return 0;
+}
+
+/**
+ * ibmvmc_send_add_buffer_resp - Add Buffer Response
+ *
+ * @adapter:	crq_server_adapter struct
+ * @status:	Status field
+ * @hmc_session: HMC Session field
+ * @hmc_index:	HMC Index field
+ * @buffer_id:	Buffer Id field
+ *
+ * This command is sent by the management partition to the hypervisor in
+ * response to the Add Buffer message. The Status field indicates the result of
+ * the command.
+ *
+ * Return:
+ *	0 - Success
+ */
+static int ibmvmc_send_add_buffer_resp(struct crq_server_adapter *adapter,
+				       u8 status, u8 hmc_session,
+				       u8 hmc_index, u16 buffer_id)
+{
+	struct ibmvmc_crq_msg crq_msg;
+	__be64 *crq_as_u64 = (__be64 *)&crq_msg;
+
+	dev_dbg(adapter->dev, "CRQ send: add_buffer_resp\n");
+	crq_msg.valid = 0x80;
+	crq_msg.type = VMC_MSG_ADD_BUF_RESP;
+	crq_msg.status = status;
+	crq_msg.var1.rsvd = 0;
+	crq_msg.hmc_session = hmc_session;
+	crq_msg.hmc_index = hmc_index;
+	crq_msg.var2.buffer_id = cpu_to_be16(buffer_id);
+	crq_msg.rsvd = 0;
+	crq_msg.var3.rsvd = 0;
+
+	ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+			be64_to_cpu(crq_as_u64[1]));
+
+	return 0;
+}
+
+/**
+ * ibmvmc_send_rem_buffer_resp - Remove Buffer Response
+ *
+ * @adapter:	crq_server_adapter struct
+ * @status:	Status field
+ * @hmc_session: HMC Session field
+ * @hmc_index:	HMC Index field
+ * @buffer_id:	Buffer Id field
+ *
+ * This command is sent by the management partition to the hypervisor in
+ * response to the Remove Buffer message. The Buffer ID field indicates
+ * which buffer the management partition selected to remove. The Status
+ * field indicates the result of the command.
+ *
+ * Return:
+ *	0 - Success
+ */
+static int ibmvmc_send_rem_buffer_resp(struct crq_server_adapter *adapter,
+				       u8 status, u8 hmc_session,
+				       u8 hmc_index, u16 buffer_id)
+{
+	struct ibmvmc_crq_msg crq_msg;
+	__be64 *crq_as_u64 = (__be64 *)&crq_msg;
+
+	dev_dbg(adapter->dev, "CRQ send: rem_buffer_resp\n");
+	crq_msg.valid = 0x80;
+	crq_msg.type = VMC_MSG_REM_BUF_RESP;
+	crq_msg.status = status;
+	crq_msg.var1.rsvd = 0;
+	crq_msg.hmc_session = hmc_session;
+	crq_msg.hmc_index = hmc_index;
+	crq_msg.var2.buffer_id = cpu_to_be16(buffer_id);
+	crq_msg.rsvd = 0;
+	crq_msg.var3.rsvd = 0;
+
+	ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+			be64_to_cpu(crq_as_u64[1]));
+
+	return 0;
+}
+
+/**
+ * ibmvmc_send_msg - Signal Message
+ *
+ * @adapter:	crq_server_adapter struct
+ * @buffer:	ibmvmc_buffer struct
+ * @hmc:	ibmvmc_hmc struct
+ * @msg_length:	message length field
+ *
+ * This command is sent between the management partition and the hypervisor
+ * in order to signal the arrival of an HMC protocol message. The command
+ * can be sent by both the management partition and the hypervisor. It is
+ * used for all traffic between the Novalink application and the hypervisor,
+ * regardless of who initiated the communication.
+ *
+ * There is no response to this message.
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static int ibmvmc_send_msg(struct crq_server_adapter *adapter,
+			   struct ibmvmc_buffer *buffer,
+			   struct ibmvmc_hmc *hmc, int msg_len)
+{
+	struct ibmvmc_crq_msg crq_msg;
+	__be64 *crq_as_u64 = (__be64 *)&crq_msg;
+	int rc = 0;
+
+	dev_dbg(adapter->dev, "CRQ send: rdma to HV\n");
+	rc = h_copy_rdma(msg_len,
+			 adapter->liobn,
+			 buffer->dma_addr_local,
+			 adapter->riobn,
+			 buffer->dma_addr_remote);
+	if (rc) {
+		dev_err(adapter->dev, "Error in send_msg, h_copy_rdma rc 0x%x\n",
+			rc);
+		return rc;
+	}
+
+	crq_msg.valid = 0x80;
+	crq_msg.type = VMC_MSG_SIGNAL;
+	crq_msg.status = 0;
+	crq_msg.var1.rsvd = 0;
+	crq_msg.hmc_session = hmc->session;
+	crq_msg.hmc_index = hmc->index;
+	crq_msg.var2.buffer_id = cpu_to_be16(buffer->id);
+	crq_msg.var3.msg_len = cpu_to_be32(msg_len);
+	dev_dbg(adapter->dev, "CRQ send: msg to HV 0x%llx 0x%llx\n",
+		be64_to_cpu(crq_as_u64[0]), be64_to_cpu(crq_as_u64[1]));
+
+	buffer->owner = VMC_BUF_OWNER_HV;
+	ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+			be64_to_cpu(crq_as_u64[1]));
+
+	return rc;
+}
+
+/**
+ * ibmvmc_open - Open Session
+ *
+ * @inode:	inode struct
+ * @file:	file struct
+ *
+ * Return:
+ *	0 - Success
+ */
+static int ibmvmc_open(struct inode *inode, struct file *file)
+{
+	struct ibmvmc_file_session *session;
+	int rc = 0;
+
+	pr_debug("%s: inode = 0x%lx, file = 0x%lx, state = 0x%x\n", __func__,
+		 (unsigned long)inode, (unsigned long)file,
+		 ibmvmc.state);
+
+	session = kzalloc(sizeof(*session), GFP_KERNEL);
+	session->file = file;
+	file->private_data = session;
+
+	return rc;
+}
+
+/**
+ * ibmvmc_close - Close Session
+ *
+ * @inode:	inode struct
+ * @file:	file struct
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static int ibmvmc_close(struct inode *inode, struct file *file)
+{
+	struct ibmvmc_file_session *session;
+	struct ibmvmc_hmc *hmc;
+	int rc = 0;
+	unsigned long flags;
+
+	pr_debug("%s: file = 0x%lx, state = 0x%x\n", __func__,
+		 (unsigned long)file, ibmvmc.state);
+
+	session = file->private_data;
+	if (!session)
+		return -EIO;
+
+	hmc = session->hmc;
+	if (hmc) {
+		if (!hmc->adapter)
+			return -EIO;
+
+		if (ibmvmc.state == ibmvmc_state_failed) {
+			dev_warn(hmc->adapter->dev, "close: state_failed\n");
+			return -EIO;
+		}
+
+		spin_lock_irqsave(&hmc->lock, flags);
+		if (hmc->state >= ibmhmc_state_opening) {
+			rc = ibmvmc_send_close(hmc);
+			if (rc)
+				dev_warn(hmc->adapter->dev, "close: send_close failed.\n");
+		}
+		spin_unlock_irqrestore(&hmc->lock, flags);
+	}
+
+	kzfree(session);
+
+	return rc;
+}
+
+/**
+ * ibmvmc_read - Read
+ *
+ * @file:	file struct
+ * @buf:	Character buffer
+ * @nbytes:	Size in bytes
+ * @ppos:	Offset
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static ssize_t ibmvmc_read(struct file *file, char *buf, size_t nbytes,
+			   loff_t *ppos)
+{
+	struct ibmvmc_file_session *session;
+	struct ibmvmc_hmc *hmc;
+	struct crq_server_adapter *adapter;
+	struct ibmvmc_buffer *buffer;
+	ssize_t n;
+	ssize_t retval = 0;
+	unsigned long flags;
+	DEFINE_WAIT(wait);
+
+	pr_debug("ibmvmc: read: file = 0x%lx, buf = 0x%lx, nbytes = 0x%lx\n",
+		 (unsigned long)file, (unsigned long)buf,
+		 (unsigned long)nbytes);
+
+	if (nbytes == 0)
+		return 0;
+
+	if (nbytes > ibmvmc.max_mtu) {
+		pr_warn("ibmvmc: read: nbytes invalid 0x%x\n",
+			(unsigned int)nbytes);
+		return -EINVAL;
+	}
+
+	session = file->private_data;
+	if (!session) {
+		pr_warn("ibmvmc: read: no session\n");
+		return -EIO;
+	}
+
+	hmc = session->hmc;
+	if (!hmc) {
+		pr_warn("ibmvmc: read: no hmc\n");
+		return -EIO;
+	}
+
+	adapter = hmc->adapter;
+	if (!adapter) {
+		pr_warn("ibmvmc: read: no adapter\n");
+		return -EIO;
+	}
+
+	do {
+		prepare_to_wait(&ibmvmc_read_wait, &wait, TASK_INTERRUPTIBLE);
+
+		spin_lock_irqsave(&hmc->lock, flags);
+		if (hmc->queue_tail != hmc->queue_head)
+			/* Data is available */
+			break;
+
+		spin_unlock_irqrestore(&hmc->lock, flags);
+
+		if (!session->valid) {
+			retval = -EBADFD;
+			goto out;
+		}
+		if (file->f_flags & O_NONBLOCK) {
+			retval = -EAGAIN;
+			goto out;
+		}
+
+		schedule();
+
+		if (signal_pending(current)) {
+			retval = -ERESTARTSYS;
+			goto out;
+		}
+	} while (1);
+
+	buffer = &(hmc->buffer[hmc->queue_outbound_msgs[hmc->queue_tail]]);
+	hmc->queue_tail++;
+	if (hmc->queue_tail == ibmvmc_max_buf_pool_size)
+		hmc->queue_tail = 0;
+	spin_unlock_irqrestore(&hmc->lock, flags);
+
+	nbytes = min_t(size_t, nbytes, buffer->msg_len);
+	n = copy_to_user((void *)buf, buffer->real_addr_local, nbytes);
+	dev_dbg(adapter->dev, "read: copy to user nbytes = 0x%lx.\n", nbytes);
+	ibmvmc_free_hmc_buffer(hmc, buffer);
+	retval = nbytes;
+
+	if (n) {
+		dev_warn(adapter->dev, "read: copy to user failed.\n");
+		retval = -EFAULT;
+	}
+
+ out:
+	finish_wait(&ibmvmc_read_wait, &wait);
+	dev_dbg(adapter->dev, "read: out %ld\n", retval);
+	return retval;
+}
+
+/**
+ * ibmvmc_poll - Poll
+ *
+ * @file:	file struct
+ * @wait:	Poll Table
+ *
+ * Return:
+ *	poll.h return values
+ */
+static unsigned int ibmvmc_poll(struct file *file, poll_table *wait)
+{
+	struct ibmvmc_file_session *session;
+	struct ibmvmc_hmc *hmc;
+	unsigned int mask = 0;
+
+	session = file->private_data;
+	if (!session)
+		return 0;
+
+	hmc = session->hmc;
+	if (!hmc)
+		return 0;
+
+	poll_wait(file, &ibmvmc_read_wait, wait);
+
+	if (hmc->queue_head != hmc->queue_tail)
+		mask |= POLLIN | POLLRDNORM;
+
+	return mask;
+}
+
+/**
+ * ibmvmc_write - Write
+ *
+ * @file:	file struct
+ * @buf:	Character buffer
+ * @count:	Count field
+ * @ppos:	Offset
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static ssize_t ibmvmc_write(struct file *file, const char *buffer,
+			    size_t count, loff_t *ppos)
+{
+	struct ibmvmc_buffer *vmc_buffer;
+	struct ibmvmc_file_session *session;
+	struct crq_server_adapter *adapter;
+	struct ibmvmc_hmc *hmc;
+	unsigned char *buf;
+	unsigned long flags;
+	size_t bytes;
+	const char *p = buffer;
+	size_t c = count;
+	int ret = 0;
+
+	session = file->private_data;
+	if (!session)
+		return -EIO;
+
+	hmc = session->hmc;
+	if (!hmc)
+		return -EIO;
+
+	spin_lock_irqsave(&hmc->lock, flags);
+	if (hmc->state == ibmhmc_state_free) {
+		/* HMC connection is not valid (possibly was reset under us). */
+		ret = -EIO;
+		goto out;
+	}
+
+	adapter = hmc->adapter;
+	if (!adapter) {
+		ret = -EIO;
+		goto out;
+	}
+
+	if (count > ibmvmc.max_mtu) {
+		dev_warn(adapter->dev, "invalid buffer size 0x%lx\n",
+			 (unsigned long)count);
+		ret = -EIO;
+		goto out;
+	}
+
+	/* Waiting for the open resp message to the ioctl(1) - retry */
+	if (hmc->state == ibmhmc_state_opening) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	/* Make sure the ioctl() was called & the open msg sent, and that
+	 * the HMC connection has not failed.
+	 */
+	if (hmc->state != ibmhmc_state_ready) {
+		ret = -EIO;
+		goto out;
+	}
+
+	vmc_buffer = ibmvmc_get_valid_hmc_buffer(hmc->index);
+	if (!vmc_buffer) {
+		/* No buffer available for the msg send, or we have not yet
+		 * completed the open/open_resp sequence.  Retry until this is
+		 * complete.
+		 */
+		ret = -EBUSY;
+		goto out;
+	}
+	if (!vmc_buffer->real_addr_local) {
+		dev_err(adapter->dev, "no buffer storage assigned\n");
+		ret = -EIO;
+		goto out;
+	}
+	buf = vmc_buffer->real_addr_local;
+
+	while (c > 0) {
+		bytes = min_t(size_t, c, vmc_buffer->size);
+
+		bytes -= copy_from_user(buf, p, bytes);
+		if (!bytes) {
+			ret = -EFAULT;
+			goto out;
+		}
+		c -= bytes;
+		p += bytes;
+	}
+	if (p == buffer)
+		goto out;
+
+	file->f_path.dentry->d_inode->i_mtime = current_time(file_inode(file));
+	mark_inode_dirty(file->f_path.dentry->d_inode);
+
+	dev_dbg(adapter->dev, "write: file = 0x%lx, count = 0x%lx\n",
+		(unsigned long)file, (unsigned long)count);
+
+	ibmvmc_send_msg(adapter, vmc_buffer, hmc, count);
+	ret = p - buffer;
+ out:
+	spin_unlock_irqrestore(&hmc->lock, flags);
+	return (ssize_t)(ret);
+}
+
+/**
+ * ibmvmc_setup_hmc - Setup the HMC
+ *
+ * @session:	ibmvmc_file_session struct
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static long ibmvmc_setup_hmc(struct ibmvmc_file_session *session)
+{
+	struct ibmvmc_hmc *hmc;
+	unsigned int valid, free, index;
+
+	if (ibmvmc.state == ibmvmc_state_failed) {
+		pr_warn("ibmvmc: Reserve HMC: state_failed\n");
+		return -EIO;
+	}
+
+	if (ibmvmc.state < ibmvmc_state_ready) {
+		pr_warn("ibmvmc: Reserve HMC: not state_ready\n");
+		return -EAGAIN;
+	}
+
+	/* Device is busy until capabilities have been exchanged and we
+	 * have a generic buffer for each possible HMC connection.
+	 */
+	for (index = 0; index <= ibmvmc.max_hmc_index; index++) {
+		valid = 0;
+		ibmvmc_count_hmc_buffers(index, &valid, &free);
+		if (valid == 0) {
+			pr_warn("ibmvmc: buffers not ready for index %d\n",
+				index);
+			return -ENOBUFS;
+		}
+	}
+
+	/* Get an hmc object, and transition to ibmhmc_state_initial */
+	hmc = ibmvmc_get_free_hmc();
+	if (!hmc) {
+		pr_warn("%s: free hmc not found\n", __func__);
+		return -EBUSY;
+	}
+
+	hmc->session = hmc->session + 1;
+	if (hmc->session == 0xff)
+		hmc->session = 1;
+
+	session->hmc = hmc;
+	hmc->adapter = &ibmvmc_adapter;
+	hmc->file_session = session;
+	session->valid = 1;
+
+	return 0;
+}
+
+/**
+ * ibmvmc_ioctl_sethmcid - IOCTL Set HMC ID
+ *
+ * @session:	ibmvmc_file_session struct
+ * @new_hmc_id:	HMC id field
+ *
+ * IOCTL command to setup the hmc id
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static long ibmvmc_ioctl_sethmcid(struct ibmvmc_file_session *session,
+				  unsigned char __user *new_hmc_id)
+{
+	struct ibmvmc_hmc *hmc;
+	struct ibmvmc_buffer *buffer;
+	size_t bytes;
+	char print_buffer[HMC_ID_LEN + 1];
+	unsigned long flags;
+	long rc = 0;
+
+	/* Reserve HMC session */
+	hmc = session->hmc;
+	if (!hmc) {
+		rc = ibmvmc_setup_hmc(session);
+		if (rc)
+			return rc;
+
+		hmc = session->hmc;
+		if (!hmc) {
+			pr_err("ibmvmc: setup_hmc success but no hmc\n");
+			return -EIO;
+		}
+	}
+
+	if (hmc->state != ibmhmc_state_initial) {
+		pr_warn("ibmvmc: sethmcid: invalid state to send open 0x%x\n",
+			hmc->state);
+		return -EIO;
+	}
+
+	bytes = copy_from_user(hmc->hmc_id, new_hmc_id, HMC_ID_LEN);
+	if (bytes)
+		return -EFAULT;
+
+	/* Send Open Session command */
+	spin_lock_irqsave(&hmc->lock, flags);
+	buffer = ibmvmc_get_valid_hmc_buffer(hmc->index);
+	spin_unlock_irqrestore(&hmc->lock, flags);
+
+	if (!buffer || !buffer->real_addr_local) {
+		pr_warn("ibmvmc: sethmcid: no buffer available\n");
+		return -EIO;
+	}
+
+	/* Make sure buffer is NULL terminated before trying to print it */
+	memset(print_buffer, 0, HMC_ID_LEN + 1);
+	strncpy(print_buffer, hmc->hmc_id, HMC_ID_LEN);
+	pr_info("ibmvmc: sethmcid: Set HMC ID: \"%s\"\n", print_buffer);
+
+	memcpy(buffer->real_addr_local, hmc->hmc_id, HMC_ID_LEN);
+	/* RDMA over ID, send open msg, change state to ibmhmc_state_opening */
+	rc = ibmvmc_send_open(buffer, hmc);
+
+	return rc;
+}
+
+/**
+ * ibmvmc_ioctl_query - IOCTL Query
+ *
+ * @session:	ibmvmc_file_session struct
+ * @ret_struct:	ibmvmc_query_struct
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static long ibmvmc_ioctl_query(struct ibmvmc_file_session *session,
+			       struct ibmvmc_query_struct __user *ret_struct)
+{
+	struct ibmvmc_query_struct query_struct;
+	size_t bytes;
+
+	memset(&query_struct, 0, sizeof(query_struct));
+	query_struct.have_vmc = (ibmvmc.state > ibmvmc_state_initial);
+	query_struct.state = ibmvmc.state;
+	query_struct.vmc_drc_index = ibmvmc.vmc_drc_index;
+
+	bytes = copy_to_user(ret_struct, &query_struct,
+			     sizeof(query_struct));
+	if (bytes)
+		return -EFAULT;
+
+	return 0;
+}
+
+/**
+ * ibmvmc_ioctl_requestvmc - IOCTL Request VMC
+ *
+ * @session:	ibmvmc_file_session struct
+ * @ret_vmc_index:	VMC Index
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static long ibmvmc_ioctl_requestvmc(struct ibmvmc_file_session *session,
+				    u32 __user *ret_vmc_index)
+{
+	/* TODO: (adreznec) Add locking to control multiple process access */
+	size_t bytes;
+	long rc;
+	u32 vmc_drc_index;
+
+	/* Call to request the VMC device from phyp*/
+	rc = h_request_vmc(&vmc_drc_index);
+	pr_debug("ibmvmc: requestvmc: H_REQUEST_VMC rc = 0x%lx\n", rc);
+
+	if (rc == H_SUCCESS) {
+		rc = 0;
+	} else if (rc == H_FUNCTION) {
+		pr_err("ibmvmc: requestvmc: h_request_vmc not supported\n");
+		return -EPERM;
+	} else if (rc == H_AUTHORITY) {
+		pr_err("ibmvmc: requestvmc: hypervisor denied vmc request\n");
+		return -EPERM;
+	} else if (rc == H_HARDWARE) {
+		pr_err("ibmvmc: requestvmc: hypervisor hardware fault\n");
+		return -EIO;
+	} else if (rc == H_RESOURCE) {
+		pr_err("ibmvmc: requestvmc: vmc resource unavailable\n");
+		return -ENODEV;
+	} else if (rc == H_NOT_AVAILABLE) {
+		pr_err("ibmvmc: requestvmc: system cannot be vmc managed\n");
+		return -EPERM;
+	} else if (rc == H_PARAMETER) {
+		pr_err("ibmvmc: requestvmc: invalid parameter\n");
+		return -EINVAL;
+	}
+
+	/* Success, set the vmc index in global struct */
+	ibmvmc.vmc_drc_index = vmc_drc_index;
+
+	bytes = copy_to_user(ret_vmc_index, &vmc_drc_index,
+			     sizeof(*ret_vmc_index));
+	if (bytes) {
+		pr_warn("ibmvmc: requestvmc: copy to user failed.\n");
+		return -EFAULT;
+	}
+	return rc;
+}
+
+/**
+ * ibmvmc_ioctl - IOCTL
+ *
+ * @session:	ibmvmc_file_session struct
+ * @cmd:	cmd field
+ * @arg:	Argument field
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static long ibmvmc_ioctl(struct file *file,
+			 unsigned int cmd, unsigned long arg)
+{
+	struct ibmvmc_file_session *session = file->private_data;
+
+	pr_debug("ibmvmc: ioctl file=0x%lx, cmd=0x%x, arg=0x%lx, ses=0x%lx\n",
+		 (unsigned long)file, cmd, arg,
+		 (unsigned long)session);
+
+	if (!session) {
+		pr_warn("ibmvmc: ioctl: no session\n");
+		return -EIO;
+	}
+
+	switch (cmd) {
+	case VMC_IOCTL_SETHMCID:
+		return ibmvmc_ioctl_sethmcid(session,
+			(unsigned char __user *)arg);
+	case VMC_IOCTL_QUERY:
+		return ibmvmc_ioctl_query(session,
+			(struct ibmvmc_query_struct __user *)arg);
+	case VMC_IOCTL_REQUESTVMC:
+		return ibmvmc_ioctl_requestvmc(session,
+			(unsigned int __user *)arg);
+	default:
+		pr_warn("ibmvmc: unknown ioctl 0x%x\n", cmd);
+		return -EINVAL;
+	}
+}
+
+static const struct file_operations ibmvmc_fops = {
+	.owner		= THIS_MODULE,
+	.read		= ibmvmc_read,
+	.write		= ibmvmc_write,
+	.poll		= ibmvmc_poll,
+	.unlocked_ioctl	= ibmvmc_ioctl,
+	.open           = ibmvmc_open,
+	.release        = ibmvmc_close,
+};
+
+/**
+ * ibmvmc_add_buffer - Add Buffer
+ *
+ * @adapter: crq_server_adapter struct
+ * @crq:	ibmvmc_crq_msg struct
+ *
+ * This message transfers a buffer from hypervisor ownership to management
+ * partition ownership. The LIOBA is obtained from the virtual TCE table
+ * associated with the hypervisor side of the VMC device, and points to a
+ * buffer of size MTU (as established in the capabilities exchange).
+ *
+ * Typical flow for ading buffers:
+ * 1. A new Novalink connection is opened by the management partition.
+ * 2. The hypervisor assigns new buffers for the traffic associated with
+ *	that connection.
+ * 3. The hypervisor sends VMC Add Buffer messages to the management
+ *	partition, informing it of the new buffers.
+ * 4. The hypervisor sends an HMC protocol message (to the Novalink application)
+ *	notifying it of the new buffers. This informs the application that
+ *	it has buffers available for sending HMC commands.
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static int ibmvmc_add_buffer(struct crq_server_adapter *adapter,
+			     struct ibmvmc_crq_msg *crq)
+{
+	struct ibmvmc_buffer *buffer;
+	u8 hmc_index;
+	u8 hmc_session;
+	u16 buffer_id;
+	unsigned long flags;
+	int rc = 0;
+
+	if (!crq)
+		return -1;
+
+	hmc_session = crq->hmc_session;
+	hmc_index = crq->hmc_index;
+	buffer_id = be16_to_cpu(crq->var2.buffer_id);
+
+	if (hmc_index > ibmvmc.max_hmc_index) {
+		dev_err(adapter->dev, "add_buffer: invalid hmc_index = 0x%x\n",
+			hmc_index);
+		ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INVALID_HMC_INDEX,
+					    hmc_session, hmc_index, buffer_id);
+		return -1;
+	}
+
+	if (buffer_id >= ibmvmc.max_buffer_pool_size) {
+		dev_err(adapter->dev, "add_buffer: invalid buffer_id = 0x%x\n",
+			buffer_id);
+		ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INVALID_BUFFER_ID,
+					    hmc_session, hmc_index, buffer_id);
+		return -1;
+	}
+
+	spin_lock_irqsave(&hmcs[hmc_index].lock, flags);
+	buffer = &hmcs[hmc_index].buffer[buffer_id];
+
+	if (buffer->real_addr_local || buffer->dma_addr_local) {
+		dev_warn(adapter->dev, "add_buffer: already allocated id = 0x%lx\n",
+			 (unsigned long)buffer_id);
+		spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+		ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INVALID_BUFFER_ID,
+					    hmc_session, hmc_index, buffer_id);
+		return -1;
+	}
+
+	buffer->real_addr_local = alloc_dma_buffer(to_vio_dev(adapter->dev),
+						   ibmvmc.max_mtu,
+						   &buffer->dma_addr_local);
+
+	if (!buffer->real_addr_local) {
+		dev_err(adapter->dev, "add_buffer: alloc_dma_buffer failed.\n");
+		spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+		ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INTERFACE_FAILURE,
+					    hmc_session, hmc_index, buffer_id);
+		return -1;
+	}
+
+	buffer->dma_addr_remote = be32_to_cpu(crq->var3.lioba);
+	buffer->size = ibmvmc.max_mtu;
+	buffer->owner = crq->var1.owner;
+	buffer->free = 1;
+	/* Must ensure valid==1 is observable only after all other fields are */
+	dma_wmb();
+	buffer->valid = 1;
+	buffer->id = buffer_id;
+
+	dev_dbg(adapter->dev, "add_buffer: successfully added a buffer:\n");
+	dev_dbg(adapter->dev, "   index: %d, session: %d, buffer: 0x%x, owner: %d\n",
+		hmc_index, hmc_session, buffer_id, buffer->owner);
+	dev_dbg(adapter->dev, "   local: 0x%x, remote: 0x%x\n",
+		(u32)buffer->dma_addr_local,
+		(u32)buffer->dma_addr_remote);
+	spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+
+	ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_SUCCESS, hmc_session,
+				    hmc_index, buffer_id);
+
+	return rc;
+}
+
+/**
+ * ibmvmc_rem_buffer - Remove Buffer
+ *
+ * @adapter: crq_server_adapter struct
+ * @crq:	ibmvmc_crq_msg struct
+ *
+ * This message requests an HMC buffer to be transferred from management
+ * partition ownership to hypervisor ownership. The management partition may
+ * not be able to satisfy the request at a particular point in time if all its
+ * buffers are in use. The management partition requires a depth of at least
+ * one inbound buffer to allow Novalink commands to flow to the hypervisor. It
+ * is, therefore, an interface error for the hypervisor to attempt to remove the
+ * management partition's last buffer.
+ *
+ * The hypervisor is expected to manage buffer usage with the Novalink
+ * application directly and inform the management partition when buffers may be
+ * removed. The typical flow for removing buffers:
+ *
+ * 1. The Novalink application no longer needs a communication path to a
+ *	particular hypervisor function. That function is closed.
+ * 2. The hypervisor and the Novalink application quiesce all traffic to that
+ *	function. The hypervisor requests a reduction in buffer pool size.
+ * 3. The Novalink application acknowledges the reduction in buffer pool size.
+ * 4. The hypervisor sends a Remove Buffer message to the management partition,
+ *	informing it of the reduction in buffers.
+ * 5. The management partition verifies it can remove the buffer. This is
+ *	possible if buffers have been quiesced.
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+/*
+ * The hypervisor requested that we pick an unused buffer, and return it.
+ * Before sending the buffer back, we free any storage associated with the
+ * buffer.
+ */
+static int ibmvmc_rem_buffer(struct crq_server_adapter *adapter,
+			     struct ibmvmc_crq_msg *crq)
+{
+	struct ibmvmc_buffer *buffer;
+	u8 hmc_index;
+	u8 hmc_session;
+	u16 buffer_id = 0;
+	unsigned long flags;
+	int rc = 0;
+
+	if (!crq)
+		return -1;
+
+	hmc_session = crq->hmc_session;
+	hmc_index = crq->hmc_index;
+
+	if (hmc_index > ibmvmc.max_hmc_index) {
+		dev_warn(adapter->dev, "rem_buffer: invalid hmc_index = 0x%x\n",
+			 hmc_index);
+		ibmvmc_send_rem_buffer_resp(adapter, VMC_MSG_INVALID_HMC_INDEX,
+					    hmc_session, hmc_index, buffer_id);
+		return -1;
+	}
+
+	spin_lock_irqsave(&hmcs[hmc_index].lock, flags);
+	buffer = ibmvmc_get_free_hmc_buffer(adapter, hmc_index);
+	if (!buffer) {
+		dev_info(adapter->dev, "rem_buffer: no buffer to remove\n");
+		spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+		ibmvmc_send_rem_buffer_resp(adapter, VMC_MSG_NO_BUFFER,
+					    hmc_session, hmc_index,
+					    VMC_INVALID_BUFFER_ID);
+		return -1;
+	}
+
+	buffer_id = buffer->id;
+
+	if (buffer->valid)
+		free_dma_buffer(to_vio_dev(adapter->dev),
+				ibmvmc.max_mtu,
+				buffer->real_addr_local,
+				buffer->dma_addr_local);
+
+	memset(buffer, 0, sizeof(struct ibmvmc_buffer));
+	spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+
+	dev_dbg(adapter->dev, "rem_buffer: removed buffer 0x%x.\n", buffer_id);
+	ibmvmc_send_rem_buffer_resp(adapter, VMC_MSG_SUCCESS, hmc_session,
+				    hmc_index, buffer_id);
+
+	return rc;
+}
+
+static int ibmvmc_recv_msg(struct crq_server_adapter *adapter,
+			   struct ibmvmc_crq_msg *crq)
+{
+	struct ibmvmc_buffer *buffer;
+	struct ibmvmc_hmc *hmc;
+	unsigned long msg_len;
+	u8 hmc_index;
+	u8 hmc_session;
+	u16 buffer_id;
+	unsigned long flags;
+	int rc = 0;
+
+	if (!crq)
+		return -1;
+
+	/* Hypervisor writes CRQs directly into our memory in big endian */
+	dev_dbg(adapter->dev, "Recv_msg: msg from HV 0x%016llx 0x%016llx\n",
+		be64_to_cpu(*((unsigned long *)crq)),
+		be64_to_cpu(*(((unsigned long *)crq) + 1)));
+
+	hmc_session = crq->hmc_session;
+	hmc_index = crq->hmc_index;
+	buffer_id = be16_to_cpu(crq->var2.buffer_id);
+	msg_len = be32_to_cpu(crq->var3.msg_len);
+
+	if (hmc_index > ibmvmc.max_hmc_index) {
+		dev_err(adapter->dev, "Recv_msg: invalid hmc_index = 0x%x\n",
+			hmc_index);
+		ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INVALID_HMC_INDEX,
+					    hmc_session, hmc_index, buffer_id);
+		return -1;
+	}
+
+	if (buffer_id >= ibmvmc.max_buffer_pool_size) {
+		dev_err(adapter->dev, "Recv_msg: invalid buffer_id = 0x%x\n",
+			buffer_id);
+		ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INVALID_BUFFER_ID,
+					    hmc_session, hmc_index, buffer_id);
+		return -1;
+	}
+
+	hmc = &hmcs[hmc_index];
+	spin_lock_irqsave(&hmc->lock, flags);
+
+	if (hmc->state == ibmhmc_state_free) {
+		dev_err(adapter->dev, "Recv_msg: invalid hmc state = 0x%x\n",
+			hmc->state);
+		/* HMC connection is not valid (possibly was reset under us). */
+		spin_unlock_irqrestore(&hmc->lock, flags);
+		return -1;
+	}
+
+	buffer = &hmc->buffer[buffer_id];
+
+	if (buffer->valid == 0 || buffer->owner == VMC_BUF_OWNER_ALPHA) {
+		dev_err(adapter->dev, "Recv_msg: not valid, or not HV.  0x%x 0x%x\n",
+			buffer->valid, buffer->owner);
+		spin_unlock_irqrestore(&hmc->lock, flags);
+		return -1;
+	}
+
+	/* RDMA the data into the partition. */
+	rc = h_copy_rdma(msg_len,
+			 adapter->riobn,
+			 buffer->dma_addr_remote,
+			 adapter->liobn,
+			 buffer->dma_addr_local);
+
+	dev_dbg(adapter->dev, "Recv_msg: msg_len = 0x%x, buffer_id = 0x%x, queue_head = 0x%x, hmc_idx = 0x%x\n",
+		(unsigned int)msg_len, (unsigned int)buffer_id,
+		(unsigned int)hmc->queue_head, (unsigned int)hmc_index);
+	buffer->msg_len = msg_len;
+	buffer->free = 0;
+	buffer->owner = VMC_BUF_OWNER_ALPHA;
+
+	if (rc) {
+		dev_err(adapter->dev, "Failure in recv_msg: h_copy_rdma = 0x%x\n",
+			rc);
+		spin_unlock_irqrestore(&hmc->lock, flags);
+		return -1;
+	}
+
+	/* Must be locked because read operates on the same data */
+	hmc->queue_outbound_msgs[hmc->queue_head] = buffer_id;
+	hmc->queue_head++;
+	if (hmc->queue_head == ibmvmc_max_buf_pool_size)
+		hmc->queue_head = 0;
+
+	if (hmc->queue_head == hmc->queue_tail)
+		dev_err(adapter->dev, "outbound buffer queue wrapped.\n");
+
+	spin_unlock_irqrestore(&hmc->lock, flags);
+
+	wake_up_interruptible(&ibmvmc_read_wait);
+
+	return 0;
+}
+
+/**
+ * ibmvmc_process_capabilities - Process Capabilities
+ *
+ * @adapter:	crq_server_adapter struct
+ * @crqp:	ibmvmc_crq_msg struct
+ *
+ */
+static void ibmvmc_process_capabilities(struct crq_server_adapter *adapter,
+					struct ibmvmc_crq_msg *crqp)
+{
+	struct ibmvmc_admin_crq_msg *crq = (struct ibmvmc_admin_crq_msg *)crqp;
+
+	if ((be16_to_cpu(crq->version) >> 8) !=
+			(IBMVMC_PROTOCOL_VERSION >> 8)) {
+		dev_err(adapter->dev, "init failed, incompatible versions 0x%x 0x%x\n",
+			be16_to_cpu(crq->version),
+			IBMVMC_PROTOCOL_VERSION);
+		ibmvmc.state = ibmvmc_state_failed;
+		return;
+	}
+
+	ibmvmc.max_mtu = min_t(u32, ibmvmc_max_mtu, be32_to_cpu(crq->max_mtu));
+	ibmvmc.max_buffer_pool_size = min_t(u16, ibmvmc_max_buf_pool_size,
+					    be16_to_cpu(crq->pool_size));
+	ibmvmc.max_hmc_index = min_t(u8, ibmvmc_max_hmcs, crq->max_hmc) - 1;
+	ibmvmc.state = ibmvmc_state_ready;
+
+	dev_info(adapter->dev, "Capabilities: mtu=0x%x, pool_size=0x%x, max_hmc=0x%x\n",
+		 ibmvmc.max_mtu, ibmvmc.max_buffer_pool_size,
+		 ibmvmc.max_hmc_index);
+}
+
+/**
+ * ibmvmc_validate_hmc_session - Validate HMC Session
+ *
+ * @adapter:	crq_server_adapter struct
+ * @crq:	ibmvmc_crq_msg struct
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static int ibmvmc_validate_hmc_session(struct crq_server_adapter *adapter,
+				       struct ibmvmc_crq_msg *crq)
+{
+	unsigned char hmc_index;
+
+	hmc_index = crq->hmc_index;
+
+	if (crq->hmc_session == 0)
+		return 0;
+
+	if (hmc_index > ibmvmc.max_hmc_index)
+		return -1;
+
+	if (hmcs[hmc_index].session != crq->hmc_session) {
+		dev_warn(adapter->dev, "Drop, bad session: expected 0x%x, recv 0x%x\n",
+			 hmcs[hmc_index].session, crq->hmc_session);
+		return -1;
+	}
+
+	return 0;
+}
+
+/**
+ * ibmvmc_reset - Reset
+ *
+ * @adapter:	crq_server_adapter struct
+ * @xport_event:	export_event field
+ *
+ * Closes all HMC sessions and conditionally schedules a CRQ reset.
+ * @xport_event: If true, the partner closed their CRQ; we don't need to reset.
+ *               If false, we need to schedule a CRQ reset.
+ */
+static void ibmvmc_reset(struct crq_server_adapter *adapter, bool xport_event)
+{
+	int i;
+
+	if (ibmvmc.state != ibmvmc_state_sched_reset) {
+		dev_info(adapter->dev, "*** Reset to initial state.\n");
+		for (i = 0; i < ibmvmc_max_hmcs; i++)
+			ibmvmc_return_hmc(&hmcs[i], xport_event);
+
+		if (xport_event) {
+			/* CRQ was closed by the partner.  We don't need to do
+			 * anything except set ourself to the correct state to
+			 * handle init msgs.
+			 */
+			ibmvmc.state = ibmvmc_state_crqinit;
+		} else {
+			/* The partner did not close their CRQ - instead, we're
+			 * closing the CRQ on our end. Need to schedule this
+			 * for process context, because CRQ reset may require a
+			 * sleep.
+			 *
+			 * Setting ibmvmc.state here immediately prevents
+			 * ibmvmc_open from completing until the reset
+			 * completes in process context.
+			 */
+			ibmvmc.state = ibmvmc_state_sched_reset;
+			dev_dbg(adapter->dev, "Device reset scheduled");
+			wake_up_interruptible(&adapter->reset_wait_queue);
+		}
+	}
+}
+
+/**
+ * ibmvmc_reset_task - Reset Task
+ *
+ * @data:	Data field
+ *
+ * Performs a CRQ reset of the VMC device in process context.
+ * NOTE: This function should not be called directly, use ibmvmc_reset.
+ */
+static int ibmvmc_reset_task(void *data)
+{
+	struct crq_server_adapter *adapter = data;
+	int rc;
+
+	set_user_nice(current, -20);
+
+	while (!kthread_should_stop()) {
+		wait_event_interruptible(adapter->reset_wait_queue,
+			(ibmvmc.state == ibmvmc_state_sched_reset) ||
+			kthread_should_stop());
+
+		if (kthread_should_stop())
+			break;
+
+		dev_dbg(adapter->dev, "CRQ resetting in process context");
+		tasklet_disable(&adapter->work_task);
+
+		rc = ibmvmc_reset_crq_queue(adapter);
+
+		if (rc != H_SUCCESS && rc != H_RESOURCE) {
+			dev_err(adapter->dev, "Error initializing CRQ.  rc = 0x%x\n",
+				rc);
+			ibmvmc.state = ibmvmc_state_failed;
+		} else {
+			ibmvmc.state = ibmvmc_state_crqinit;
+
+			if (ibmvmc_send_crq(adapter, 0xC001000000000000LL, 0)
+			    != 0 && rc != H_RESOURCE)
+				dev_warn(adapter->dev, "Failed to send initialize CRQ message\n");
+		}
+
+		vio_enable_interrupts(to_vio_dev(adapter->dev));
+		tasklet_enable(&adapter->work_task);
+	}
+
+	return 0;
+}
+
+/**
+ * ibmvmc_process_open_resp - Process Open Response
+ *
+ * @crq: ibmvmc_crq_msg struct
+ * @adapter:    crq_server_adapter struct
+ *
+ * This command is sent by the hypervisor in response to the Interface
+ * Open message. When this message is received, the indicated buffer is
+ * again available for management partition use.
+ */
+static void ibmvmc_process_open_resp(struct ibmvmc_crq_msg *crq,
+				     struct crq_server_adapter *adapter)
+{
+	unsigned char hmc_index;
+	unsigned short buffer_id;
+
+	hmc_index = crq->hmc_index;
+	if (hmc_index > ibmvmc.max_hmc_index) {
+		/* Why would PHYP give an index > max negotiated? */
+		ibmvmc_reset(adapter, false);
+		return;
+	}
+
+	if (crq->status) {
+		dev_warn(adapter->dev, "open_resp: failed - status 0x%x\n",
+			 crq->status);
+		ibmvmc_return_hmc(&hmcs[hmc_index], false);
+		return;
+	}
+
+	if (hmcs[hmc_index].state == ibmhmc_state_opening) {
+		buffer_id = be16_to_cpu(crq->var2.buffer_id);
+		if (buffer_id >= ibmvmc.max_buffer_pool_size) {
+			dev_err(adapter->dev, "open_resp: invalid buffer_id = 0x%x\n",
+				buffer_id);
+			hmcs[hmc_index].state = ibmhmc_state_failed;
+		} else {
+			ibmvmc_free_hmc_buffer(&hmcs[hmc_index],
+					       &hmcs[hmc_index].buffer[buffer_id]);
+			hmcs[hmc_index].state = ibmhmc_state_ready;
+			dev_dbg(adapter->dev, "open_resp: set hmc state = ready\n");
+		}
+	} else {
+		dev_warn(adapter->dev, "open_resp: invalid hmc state (0x%x)\n",
+			 hmcs[hmc_index].state);
+	}
+}
+
+/**
+ * ibmvmc_process_close_resp - Process Close Response
+ *
+ * @crq: ibmvmc_crq_msg struct
+ * @adapter:    crq_server_adapter struct
+ *
+ * This command is sent by the hypervisor in response to the Novalink Interface
+ * Close message.
+ *
+ * If the close fails, simply reset the entire driver as the state of the VMC
+ * must be in tough shape.
+ */
+static void ibmvmc_process_close_resp(struct ibmvmc_crq_msg *crq,
+				      struct crq_server_adapter *adapter)
+{
+	unsigned char hmc_index;
+
+	hmc_index = crq->hmc_index;
+	if (hmc_index > ibmvmc.max_hmc_index) {
+		ibmvmc_reset(adapter, false);
+		return;
+	}
+
+	if (crq->status) {
+		dev_warn(adapter->dev, "close_resp: failed - status 0x%x\n",
+			 crq->status);
+		ibmvmc_reset(adapter, false);
+		return;
+	}
+
+	ibmvmc_return_hmc(&hmcs[hmc_index], false);
+}
+
+/**
+ * ibmvmc_crq_process - Process CRQ
+ *
+ * @adapter:    crq_server_adapter struct
+ * @crq:	ibmvmc_crq_msg struct
+ *
+ * Process the CRQ message based upon the type of message received.
+ *
+ */
+static void ibmvmc_crq_process(struct crq_server_adapter *adapter,
+			       struct ibmvmc_crq_msg *crq)
+{
+	switch (crq->type) {
+	case VMC_MSG_CAP_RESP:
+		dev_dbg(adapter->dev, "CRQ recv: capabilities resp (0x%x)\n",
+			crq->type);
+		if (ibmvmc.state == ibmvmc_state_capabilities)
+			ibmvmc_process_capabilities(adapter, crq);
+		else
+			dev_warn(adapter->dev, "caps msg invalid in state 0x%x\n",
+				 ibmvmc.state);
+		break;
+	case VMC_MSG_OPEN_RESP:
+		dev_dbg(adapter->dev, "CRQ recv: open resp (0x%x)\n",
+			crq->type);
+		if (ibmvmc_validate_hmc_session(adapter, crq) == 0)
+			ibmvmc_process_open_resp(crq, adapter);
+		break;
+	case VMC_MSG_ADD_BUF:
+		dev_dbg(adapter->dev, "CRQ recv: add buf (0x%x)\n",
+			crq->type);
+		if (ibmvmc_validate_hmc_session(adapter, crq) == 0)
+			ibmvmc_add_buffer(adapter, crq);
+		break;
+	case VMC_MSG_REM_BUF:
+		dev_dbg(adapter->dev, "CRQ recv: rem buf (0x%x)\n",
+			crq->type);
+		if (ibmvmc_validate_hmc_session(adapter, crq) == 0)
+			ibmvmc_rem_buffer(adapter, crq);
+		break;
+	case VMC_MSG_SIGNAL:
+		dev_dbg(adapter->dev, "CRQ recv: signal msg (0x%x)\n",
+			crq->type);
+		if (ibmvmc_validate_hmc_session(adapter, crq) == 0)
+			ibmvmc_recv_msg(adapter, crq);
+		break;
+	case VMC_MSG_CLOSE_RESP:
+		dev_dbg(adapter->dev, "CRQ recv: close resp (0x%x)\n",
+			crq->type);
+		if (ibmvmc_validate_hmc_session(adapter, crq) == 0)
+			ibmvmc_process_close_resp(crq, adapter);
+		break;
+	case VMC_MSG_CAP:
+	case VMC_MSG_OPEN:
+	case VMC_MSG_CLOSE:
+	case VMC_MSG_ADD_BUF_RESP:
+	case VMC_MSG_REM_BUF_RESP:
+		dev_warn(adapter->dev, "CRQ recv: unexpected msg (0x%x)\n",
+			 crq->type);
+		break;
+	default:
+		dev_warn(adapter->dev, "CRQ recv: unknown msg (0x%x)\n",
+			 crq->type);
+		break;
+	}
+}
+
+/**
+ * ibmvmc_handle_crq_init - Handle CRQ Init
+ *
+ * @crq:	ibmvmc_crq_msg struct
+ * @adapter:	crq_server_adapter struct
+ *
+ * Handle the type of crq initialization based on whether
+ * it is a message or a response.
+ *
+ */
+static void ibmvmc_handle_crq_init(struct ibmvmc_crq_msg *crq,
+				   struct crq_server_adapter *adapter)
+{
+	switch (crq->type) {
+	case 0x01:	/* Initialization message */
+		dev_dbg(adapter->dev, "CRQ recv: CRQ init msg - state 0x%x\n",
+			ibmvmc.state);
+		if (ibmvmc.state == ibmvmc_state_crqinit) {
+			/* Send back a response */
+			if (ibmvmc_send_crq(adapter, 0xC002000000000000,
+					    0) == 0)
+				ibmvmc_send_capabilities(adapter);
+			else
+				dev_err(adapter->dev, " Unable to send init rsp\n");
+		} else {
+			dev_err(adapter->dev, "Invalid state 0x%x mtu = 0x%x\n",
+				ibmvmc.state, ibmvmc.max_mtu);
+		}
+
+		break;
+	case 0x02:	/* Initialization response */
+		dev_dbg(adapter->dev, "CRQ recv: initialization resp msg - state 0x%x\n",
+			ibmvmc.state);
+		if (ibmvmc.state == ibmvmc_state_crqinit)
+			ibmvmc_send_capabilities(adapter);
+		break;
+	default:
+		dev_warn(adapter->dev, "Unknown crq message type 0x%lx\n",
+			 (unsigned long)crq->type);
+	}
+}
+
+/**
+ * ibmvmc_handle_crq - Handle CRQ
+ *
+ * @crq:	ibmvmc_crq_msg struct
+ * @adapter:	crq_server_adapter struct
+ *
+ * Read the command elements from the command queue and execute the
+ * requests based upon the type of crq message.
+ *
+ */
+static void ibmvmc_handle_crq(struct ibmvmc_crq_msg *crq,
+			      struct crq_server_adapter *adapter)
+{
+	switch (crq->valid) {
+	case 0xC0:		/* initialization */
+		ibmvmc_handle_crq_init(crq, adapter);
+		break;
+	case 0xFF:	/* Hypervisor telling us the connection is closed */
+		dev_warn(adapter->dev, "CRQ recv: virtual adapter failed - resetting.\n");
+		ibmvmc_reset(adapter, true);
+		break;
+	case 0x80:	/* real payload */
+		ibmvmc_crq_process(adapter, crq);
+		break;
+	default:
+		dev_warn(adapter->dev, "CRQ recv: unknown msg 0x%02x.\n",
+			 crq->valid);
+		break;
+	}
+}
+
+static void ibmvmc_task(unsigned long data)
+{
+	struct crq_server_adapter *adapter =
+		(struct crq_server_adapter *)data;
+	struct vio_dev *vdev = to_vio_dev(adapter->dev);
+	struct ibmvmc_crq_msg *crq;
+	int done = 0;
+
+	while (!done) {
+		/* Pull all the valid messages off the CRQ */
+		while ((crq = crq_queue_next_crq(&adapter->queue)) != NULL) {
+			ibmvmc_handle_crq(crq, adapter);
+			crq->valid = 0x00;
+			/* CRQ reset was requested, stop processing CRQs.
+			 * Interrupts will be re-enabled by the reset task.
+			 */
+			if (ibmvmc.state == ibmvmc_state_sched_reset)
+				return;
+		}
+
+		vio_enable_interrupts(vdev);
+		crq = crq_queue_next_crq(&adapter->queue);
+		if (crq) {
+			vio_disable_interrupts(vdev);
+			ibmvmc_handle_crq(crq, adapter);
+			crq->valid = 0x00;
+			/* CRQ reset was requested, stop processing CRQs.
+			 * Interrupts will be re-enabled by the reset task.
+			 */
+			if (ibmvmc.state == ibmvmc_state_sched_reset)
+				return;
+		} else {
+			done = 1;
+		}
+	}
+}
+
+/**
+ * ibmvmc_init_crq_queue - Init CRQ Queue
+ *
+ * @adapter:	crq_server_adapter struct
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static int ibmvmc_init_crq_queue(struct crq_server_adapter *adapter)
+{
+	struct vio_dev *vdev = to_vio_dev(adapter->dev);
+	struct crq_queue *queue = &adapter->queue;
+	int rc;
+	int retrc;
+
+	queue->msgs = (struct ibmvmc_crq_msg *)get_zeroed_page(GFP_KERNEL);
+
+	if (!queue->msgs)
+		goto malloc_failed;
+
+	queue->size = PAGE_SIZE / sizeof(*queue->msgs);
+
+	queue->msg_token = dma_map_single(adapter->dev, queue->msgs,
+					  queue->size * sizeof(*queue->msgs),
+					  DMA_BIDIRECTIONAL);
+
+	if (dma_mapping_error(adapter->dev, queue->msg_token))
+		goto map_failed;
+
+	retrc = plpar_hcall_norets(H_REG_CRQ,
+				   vdev->unit_address,
+				   queue->msg_token, PAGE_SIZE);
+	retrc = rc;
+
+	if (rc == H_RESOURCE)
+		rc = ibmvmc_reset_crq_queue(adapter);
+
+	if (rc == 2) {
+		dev_warn(adapter->dev, "Partner adapter not ready\n");
+		retrc = 0;
+	} else if (rc != 0) {
+		dev_err(adapter->dev, "Error %d opening adapter\n", rc);
+		goto reg_crq_failed;
+	}
+
+	queue->cur = 0;
+	spin_lock_init(&queue->lock);
+
+	tasklet_init(&adapter->work_task, ibmvmc_task, (unsigned long)adapter);
+
+	if (request_irq(vdev->irq,
+			ibmvmc_handle_event,
+			0, "ibmvmc", (void *)adapter) != 0) {
+		dev_err(adapter->dev, "couldn't register irq 0x%x\n",
+			vdev->irq);
+		goto req_irq_failed;
+	}
+
+	rc = vio_enable_interrupts(vdev);
+	if (rc != 0) {
+		dev_err(adapter->dev, "Error %d enabling interrupts!!!\n", rc);
+		goto req_irq_failed;
+	}
+
+	return retrc;
+
+req_irq_failed:
+	/* Cannot have any work since we either never got our IRQ registered,
+	 * or never got interrupts enabled
+	 */
+	tasklet_kill(&adapter->work_task);
+	h_free_crq(vdev->unit_address);
+reg_crq_failed:
+	dma_unmap_single(adapter->dev,
+			 queue->msg_token,
+			 queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);
+map_failed:
+	free_page((unsigned long)queue->msgs);
+malloc_failed:
+	return -ENOMEM;
+}
+
+/* Fill in the liobn and riobn fields on the adapter */
+static int read_dma_window(struct vio_dev *vdev,
+			   struct crq_server_adapter *adapter)
+{
+	const __be32 *dma_window;
+	const __be32 *prop;
+
+	/* TODO Using of_parse_dma_window would be better, but it doesn't give
+	 * a way to read multiple windows without already knowing the size of
+	 * a window or the number of windows
+	 */
+	dma_window =
+		(const __be32 *)vio_get_attribute(vdev, "ibm,my-dma-window",
+						NULL);
+	if (!dma_window) {
+		dev_warn(adapter->dev, "Couldn't find ibm,my-dma-window property\n");
+		return -1;
+	}
+
+	adapter->liobn = be32_to_cpu(*dma_window);
+	dma_window++;
+
+	prop = (const __be32 *)vio_get_attribute(vdev, "ibm,#dma-address-cells",
+						NULL);
+	if (!prop) {
+		dev_warn(adapter->dev, "Couldn't find ibm,#dma-address-cells property\n");
+		dma_window++;
+	} else {
+		dma_window += be32_to_cpu(*prop);
+	}
+
+	prop = (const __be32 *)vio_get_attribute(vdev, "ibm,#dma-size-cells",
+						NULL);
+	if (!prop) {
+		dev_warn(adapter->dev, "Couldn't find ibm,#dma-size-cells property\n");
+		dma_window++;
+	} else {
+		dma_window += be32_to_cpu(*prop);
+	}
+
+	/* dma_window should point to the second window now */
+	adapter->riobn = be32_to_cpu(*dma_window);
+
+	return 0;
+}
+
+static int ibmvmc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
+{
+	struct crq_server_adapter *adapter = &ibmvmc_adapter;
+	int rc;
+
+	dev_set_drvdata(&vdev->dev, NULL);
+	memset(adapter, 0, sizeof(*adapter));
+	adapter->dev = &vdev->dev;
+
+	dev_info(adapter->dev, "Probe for UA 0x%x\n", vdev->unit_address);
+
+	rc = read_dma_window(vdev, adapter);
+	if (rc != 0) {
+		ibmvmc.state = ibmvmc_state_failed;
+		return -1;
+	}
+
+	dev_dbg(adapter->dev, "Probe: liobn 0x%x, riobn 0x%x\n",
+		adapter->liobn, adapter->riobn);
+
+	init_waitqueue_head(&adapter->reset_wait_queue);
+	adapter->reset_task = kthread_run(ibmvmc_reset_task, adapter, "ibmvmc");
+	if (IS_ERR(adapter->reset_task)) {
+		dev_err(adapter->dev, "Failed to start reset thread\n");
+		ibmvmc.state = ibmvmc_state_failed;
+		rc = PTR_ERR(adapter->reset_task);
+		adapter->reset_task = NULL;
+		return rc;
+	}
+
+	rc = ibmvmc_init_crq_queue(adapter);
+	if (rc != 0 && rc != H_RESOURCE) {
+		dev_err(adapter->dev, "Error initializing CRQ.  rc = 0x%x\n",
+			rc);
+		ibmvmc.state = ibmvmc_state_failed;
+		goto crq_failed;
+	}
+
+	ibmvmc.state = ibmvmc_state_crqinit;
+
+	/* Try to send an initialization message.  Note that this is allowed
+	 * to fail if the other end is not acive.  In that case we just wait
+	 * for the other side to initialize.
+	 */
+	if (ibmvmc_send_crq(adapter, 0xC001000000000000LL, 0) != 0 &&
+	    rc != H_RESOURCE)
+		dev_warn(adapter->dev, "Failed to send initialize CRQ message\n");
+
+	dev_set_drvdata(&vdev->dev, adapter);
+
+	return 0;
+
+crq_failed:
+	kthread_stop(adapter->reset_task);
+	adapter->reset_task = NULL;
+	return -EPERM;
+}
+
+static int ibmvmc_remove(struct vio_dev *vdev)
+{
+	struct crq_server_adapter *adapter = dev_get_drvdata(&vdev->dev);
+
+	dev_info(adapter->dev, "Entering remove for UA 0x%x\n",
+		 vdev->unit_address);
+	ibmvmc_release_crq_queue(adapter);
+
+	return 0;
+}
+
+static struct vio_device_id ibmvmc_device_table[] = {
+	{ "ibm,vmc", "IBM,vmc" },
+	{ "", "" }
+};
+MODULE_DEVICE_TABLE(vio, ibmvmc_device_table);
+
+static struct vio_driver ibmvmc_driver = {
+	.name        = ibmvmc_driver_name,
+	.id_table    = ibmvmc_device_table,
+	.probe       = ibmvmc_probe,
+	.remove      = ibmvmc_remove,
+};
+
+static void __init ibmvmc_scrub_module_parms(void)
+{
+	if (ibmvmc_max_mtu > MAX_MTU) {
+		pr_warn("ibmvmc: Max MTU reduced to %d\n", MAX_MTU);
+		ibmvmc_max_mtu = MAX_MTU;
+	} else if (ibmvmc_max_mtu < MIN_MTU) {
+		pr_warn("ibmvmc: Max MTU increased to %d\n", MIN_MTU);
+		ibmvmc_max_mtu = MIN_MTU;
+	}
+
+	if (ibmvmc_max_buf_pool_size > MAX_BUF_POOL_SIZE) {
+		pr_warn("ibmvmc: Max buffer pool size reduced to %d\n",
+			MAX_BUF_POOL_SIZE);
+		ibmvmc_max_buf_pool_size = MAX_BUF_POOL_SIZE;
+	} else if (ibmvmc_max_buf_pool_size < MIN_BUF_POOL_SIZE) {
+		pr_warn("ibmvmc: Max buffer pool size increased to %d\n",
+			MIN_BUF_POOL_SIZE);
+		ibmvmc_max_buf_pool_size = MIN_BUF_POOL_SIZE;
+	}
+
+	if (ibmvmc_max_hmcs > MAX_HMCS) {
+		pr_warn("ibmvmc: Max HMCs reduced to %d\n", MAX_HMCS);
+		ibmvmc_max_hmcs = MAX_HMCS;
+	} else if (ibmvmc_max_hmcs < MIN_HMCS) {
+		pr_warn("ibmvmc: Max HMCs increased to %d\n", MIN_HMCS);
+		ibmvmc_max_hmcs = MIN_HMCS;
+	}
+}
+
+static struct miscdevice ibmvmc_miscdev = {
+	.name = ibmvmc_driver_name,
+	.minor = MISC_DYNAMIC_MINOR,
+	.fops = &ibmvmc_fops,
+};
+
+static int __init ibmvmc_module_init(void)
+{
+	int rc, i, j;
+
+	ibmvmc.state = ibmvmc_state_initial;
+	pr_info("ibmvmc: version %s\n", IBMVMC_DRIVER_VERSION);
+
+	rc = misc_register(&ibmvmc_miscdev);
+	if (rc) {
+		pr_err("ibmvmc: misc registration failed\n");
+		goto misc_register_failed;
+	}
+	pr_info("ibmvmc: node %d:%d\n", MISC_MAJOR,
+		ibmvmc_miscdev.minor);
+
+	/* Initialize data structures */
+	memset(hmcs, 0, sizeof(struct ibmvmc_hmc) * MAX_HMCS);
+	for (i = 0; i < MAX_HMCS; i++) {
+		spin_lock_init(&hmcs[i].lock);
+		hmcs[i].state = ibmhmc_state_free;
+		for (j = 0; j < MAX_BUF_POOL_SIZE; j++)
+			hmcs[i].queue_outbound_msgs[j] = VMC_INVALID_BUFFER_ID;
+	}
+
+	/* Sanity check module parms */
+	ibmvmc_scrub_module_parms();
+
+	/*
+	 * Initialize some reasonable values.  Might be negotiated smaller
+	 * values during the capabilities exchange.
+	 */
+	ibmvmc.max_mtu = ibmvmc_max_mtu;
+	ibmvmc.max_buffer_pool_size = ibmvmc_max_buf_pool_size;
+	ibmvmc.max_hmc_index = ibmvmc_max_hmcs - 1;
+
+	rc = vio_register_driver(&ibmvmc_driver);
+
+	if (rc) {
+		pr_err("ibmvmc: rc %d from vio_register_driver\n", rc);
+		goto vio_reg_failed;
+	}
+
+	return 0;
+
+vio_reg_failed:
+	misc_deregister(&ibmvmc_miscdev);
+misc_register_failed:
+	return rc;
+}
+
+static void __exit ibmvmc_module_exit(void)
+{
+	pr_info("ibmvmc: module exit\n");
+	vio_unregister_driver(&ibmvmc_driver);
+	misc_deregister(&ibmvmc_miscdev);
+}
+
+module_init(ibmvmc_module_init);
+module_exit(ibmvmc_module_exit);
+
+module_param_named(buf_pool_size, ibmvmc_max_buf_pool_size,
+		   int, 0644);
+MODULE_PARM_DESC(buf_pool_size, "Buffer pool size");
+module_param_named(max_hmcs, ibmvmc_max_hmcs, int, 0644);
+MODULE_PARM_DESC(max_hmcs, "Max HMCs");
+module_param_named(max_mtu, ibmvmc_max_mtu, int, 0644);
+MODULE_PARM_DESC(max_mtu, "Max MTU");
+
+MODULE_AUTHOR("Steven Royer <seroyer@linux.vnet.ibm.com>");
+MODULE_DESCRIPTION("IBM VMC");
+MODULE_VERSION(IBMVMC_DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/misc/ibmvmc.h b/drivers/misc/ibmvmc.h
new file mode 100644
index 0000000..e140ada
--- /dev/null
+++ b/drivers/misc/ibmvmc.h
@@ -0,0 +1,209 @@
+/* SPDX-License-Identifier: GPL-2.0+
+ *
+ * linux/drivers/misc/ibmvmc.h
+ *
+ * IBM Power Systems Virtual Management Channel Support.
+ *
+ * Copyright (c) 2004, 2018 IBM Corp.
+ *   Dave Engebretsen engebret@us.ibm.com
+ *   Steven Royer seroyer@linux.vnet.ibm.com
+ *   Adam Reznechek adreznec@linux.vnet.ibm.com
+ *   Bryant G. Ly <bryantly@linux.vnet.ibm.com>
+ */
+#ifndef IBMVMC_H
+#define IBMVMC_H
+
+#include <linux/types.h>
+#include <linux/cdev.h>
+
+#include <asm/vio.h>
+
+#define IBMVMC_PROTOCOL_VERSION    0x0101
+
+#define MIN_BUF_POOL_SIZE 16
+#define MIN_HMCS          1
+#define MIN_MTU           4096
+#define MAX_BUF_POOL_SIZE 64
+#define MAX_HMCS          2
+#define MAX_MTU           (4 * 4096)
+#define DEFAULT_BUF_POOL_SIZE 32
+#define DEFAULT_HMCS          1
+#define DEFAULT_MTU           4096
+#define HMC_ID_LEN        32
+
+#define VMC_INVALID_BUFFER_ID 0xFFFF
+
+/* ioctl numbers */
+#define VMC_BASE	     0xCC
+#define VMC_IOCTL_SETHMCID   _IOW(VMC_BASE, 0x00, unsigned char *)
+#define VMC_IOCTL_QUERY      _IOR(VMC_BASE, 0x01, struct ibmvmc_query_struct)
+#define VMC_IOCTL_REQUESTVMC _IOR(VMC_BASE, 0x02, u32)
+
+#define VMC_MSG_CAP          0x01
+#define VMC_MSG_CAP_RESP     0x81
+#define VMC_MSG_OPEN         0x02
+#define VMC_MSG_OPEN_RESP    0x82
+#define VMC_MSG_CLOSE        0x03
+#define VMC_MSG_CLOSE_RESP   0x83
+#define VMC_MSG_ADD_BUF      0x04
+#define VMC_MSG_ADD_BUF_RESP 0x84
+#define VMC_MSG_REM_BUF      0x05
+#define VMC_MSG_REM_BUF_RESP 0x85
+#define VMC_MSG_SIGNAL       0x06
+
+#define VMC_MSG_SUCCESS 0
+#define VMC_MSG_INVALID_HMC_INDEX 1
+#define VMC_MSG_INVALID_BUFFER_ID 2
+#define VMC_MSG_CLOSED_HMC        3
+#define VMC_MSG_INTERFACE_FAILURE 4
+#define VMC_MSG_NO_BUFFER         5
+
+#define VMC_BUF_OWNER_ALPHA 0
+#define VMC_BUF_OWNER_HV    1
+
+enum ibmvmc_states {
+	ibmvmc_state_sched_reset  = -1,
+	ibmvmc_state_initial      = 0,
+	ibmvmc_state_crqinit      = 1,
+	ibmvmc_state_capabilities = 2,
+	ibmvmc_state_ready        = 3,
+	ibmvmc_state_failed       = 4,
+};
+
+enum ibmhmc_states {
+	/* HMC connection not established */
+	ibmhmc_state_free    = 0,
+
+	/* HMC connection established (open called) */
+	ibmhmc_state_initial = 1,
+
+	/* open msg sent to HV, due to ioctl(1) call */
+	ibmhmc_state_opening = 2,
+
+	/* HMC connection ready, open resp msg from HV */
+	ibmhmc_state_ready   = 3,
+
+	/* HMC connection failure */
+	ibmhmc_state_failed  = 4,
+};
+
+struct ibmvmc_buffer {
+	u8 valid;	/* 1 when DMA storage allocated to buffer          */
+	u8 free;	/* 1 when buffer available for the Alpha Partition */
+	u8 owner;
+	u16 id;
+	u32 size;
+	u32 msg_len;
+	dma_addr_t dma_addr_local;
+	dma_addr_t dma_addr_remote;
+	void *real_addr_local;
+};
+
+struct ibmvmc_admin_crq_msg {
+	u8 valid;	/* RPA Defined           */
+	u8 type;	/* ibmvmc msg type       */
+	u8 status;	/* Response msg status. Zero is success and on failure,
+			 * either 1 - General Failure, or 2 - Invalid Version is
+			 * returned.
+			 */
+	u8 rsvd[2];
+	u8 max_hmc;	/* Max # of independent HMC connections supported */
+	__be16 pool_size;	/* Maximum number of buffers supported per HMC
+				 * connection
+				 */
+	__be32 max_mtu;		/* Maximum message size supported (bytes) */
+	__be16 crq_size;	/* # of entries available in the CRQ for the
+				 * source partition. The target partition must
+				 * limit the number of outstanding messages to
+				 * one half or less.
+				 */
+	__be16 version;	/* Indicates the code level of the management partition
+			 * or the hypervisor with the high-order byte
+			 * indicating a major version and the low-order byte
+			 * indicating a minor version.
+			 */
+};
+
+struct ibmvmc_crq_msg {
+	u8 valid;     /* RPA Defined           */
+	u8 type;      /* ibmvmc msg type       */
+	u8 status;    /* Response msg status   */
+	union {
+		u8 rsvd;  /* Reserved              */
+		u8 owner;
+	} var1;
+	u8 hmc_session;	/* Session Identifier for the current VMC connection */
+	u8 hmc_index;	/* A unique HMC Idx would be used if multiple management
+			 * applications running concurrently were desired
+			 */
+	union {
+		__be16 rsvd;
+		__be16 buffer_id;
+	} var2;
+	__be32 rsvd;
+	union {
+		__be32 rsvd;
+		__be32 lioba;
+		__be32 msg_len;
+	} var3;
+};
+
+/* an RPA command/response transport queue */
+struct crq_queue {
+	struct ibmvmc_crq_msg *msgs;
+	int size, cur;
+	dma_addr_t msg_token;
+	spinlock_t lock;
+};
+
+/* VMC server adapter settings */
+struct crq_server_adapter {
+	struct device *dev;
+	struct crq_queue queue;
+	u32 liobn;
+	u32 riobn;
+	struct tasklet_struct work_task;
+	wait_queue_head_t reset_wait_queue;
+	struct task_struct *reset_task;
+};
+
+/* Driver wide settings */
+struct ibmvmc_struct {
+	u32 state;
+	u32 max_mtu;
+	u32 max_buffer_pool_size;
+	u32 max_hmc_index;
+	struct crq_server_adapter *adapter;
+	struct cdev cdev;
+	u32 vmc_drc_index;
+};
+
+struct ibmvmc_file_session;
+
+/* Connection specific settings */
+struct ibmvmc_hmc {
+	u8 session;
+	u8 index;
+	u32 state;
+	struct crq_server_adapter *adapter;
+	spinlock_t lock;
+	unsigned char hmc_id[HMC_ID_LEN];
+	struct ibmvmc_buffer buffer[MAX_BUF_POOL_SIZE];
+	unsigned short queue_outbound_msgs[MAX_BUF_POOL_SIZE];
+	int queue_head, queue_tail;
+	struct ibmvmc_file_session *file_session;
+};
+
+struct ibmvmc_file_session {
+	struct file *file;
+	struct ibmvmc_hmc *hmc;
+	bool valid;
+};
+
+struct ibmvmc_query_struct {
+	int have_vmc;
+	int state;
+	int vmc_drc_index;
+};
+
+#endif /* __IBMVMC_H */
-- 
2.7.2

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[PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Bryant G. Ly]

This driver is a logical device which provides an
interface between the hypervisor and a management
partition.

This driver is to be used for the POWER Virtual
Management Channel Virtual Adapter on the PowerVM
platform. It provides both request/response and
async message support through the /dev/ibmvmc node.

Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Reviewed-by: Steven Royer <seroyer@linux.vnet.ibm.com>
Reviewed-by: Adam Reznechek <adreznec@linux.vnet.ibm.com>
Tested-by: Taylor Jakobson <tjakobs@us.ibm.com>
Tested-by: Brad Warrum <bwarrum@us.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
---
 Documentation/ioctl/ioctl-number.txt  |    1 +
 Documentation/misc-devices/ibmvmc.txt |  161 +++
 MAINTAINERS                           |    6 +
 arch/powerpc/include/asm/hvcall.h     |    1 +
 drivers/misc/Kconfig                  |   14 +
 drivers/misc/Makefile                 |    1 +
 drivers/misc/ibmvmc.c                 | 2415 +++++++++++++++++++++++++++++++++
 drivers/misc/ibmvmc.h                 |  209 +++
 8 files changed, 2808 insertions(+)
 create mode 100644 Documentation/misc-devices/ibmvmc.txt
 create mode 100644 drivers/misc/ibmvmc.c
 create mode 100644 drivers/misc/ibmvmc.h

diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
index 84bb74d..9851cee 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -329,6 +329,7 @@ Code  Seq#(hex)	Include File		Comments
 0xCA	80-BF	uapi/scsi/cxlflash_ioctl.h
 0xCB	00-1F	CBM serial IEC bus	in development:
 					<mailto:michael.klein@puffin.lb.shuttle.de>
+0xCC	00-0F	drivers/misc/ibmvmc.h    pseries VMC driver
 0xCD	01	linux/reiserfs_fs.h
 0xCF	02	fs/cifs/ioctl.c
 0xDB	00-0F	drivers/char/mwave/mwavepub.h
diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-devices/ibmvmc.txt
new file mode 100644
index 0000000..bae1064
--- /dev/null
+++ b/Documentation/misc-devices/ibmvmc.txt
@@ -0,0 +1,161 @@
+Kernel Driver ibmvmc
+====================
+
+Authors:
+	Dave Engebretsen <engebret@us.ibm.com>
+	Adam Reznechek <adreznec@linux.vnet.ibm.com>
+	Steven Royer <seroyer@linux.vnet.ibm.com>
+	Bryant G. Ly <bryantly@linux.vnet.ibm.com>
+
+Description
+===========
+
+The Virtual Management Channel (VMC) is a logical device which provides an
+interface between the hypervisor and a management partition. This
+management partition is intended to provide an alternative to HMC-based
+system management. In the management partition, a Novalink application
+exists which enables a system administrator to configure the system’s
+partitioning characteristics via a command line interface (CLI) or
+Representational State Transfer Application (REST). You can also manage the
+server by using PowerVC or other OpenStack solution. Support for
+conventional HMC management of the system may still be provided on a
+system; however, when an HMC is attached to the system, the VMC
+interface is disabled by the hypervisor.
+
+NovaLink runs on a Linux logical partition on a POWER8 or newer processor-
+based server that is virtualized by PowerVM. System configuration,
+maintenance, and control functions which traditionally require an HMC can
+be implemented in the Novalink using a combination of HMC to hypervisor
+interfaces and existing operating system methods. This tool provides a
+subset of the functions implemented by the HMC and enables basic partition
+configuration. The set of HMC to hypervisor messages supported by the
+Novalink component are passed to the hypervisor over a VMC interface, which
+is defined below.
+
+Virtual Management Channel (VMC)
+A logical device, called the virtual management channel (VMC), is defined
+for communicating between the Novalink application and the hypervisor.
+This device, similar to a VSCSI server device, is presented to a designated
+management partition as a virtual device and is only presented when the
+system is not HMC managed.
+This communication device borrows aspects from both VSCSI and ILLAN devices
+and is implemented using the CRQ and the RDMA interfaces. A three-way
+handshake is defined that must take place to establish that both the
+hypervisor and management partition sides of the channel are running prior
+to sending/receiving any of the protocol messages.
+This driver also utilizes Transport Event CRQs. CRQ messages that are sent
+when the hypervisor detects one of the peer partitions has abnormally
+terminated, or one side has called H_FREE_CRQ to close their CRQ.
+Two new classes of CRQ messages are introduced for the VMC device. VMC
+Administrative messages are used for each partition using the VMC to
+communicate capabilities to their partner. HMC Interface messages are used
+for the actual flow of HMC messages between the management partition and
+the hypervisor. As most HMC messages far exceed the size of a CRQ bugger,
+a virtual DMA (RMDA) of the HMC message data is done prior to each HMC
+Interface CRQ message. Only the management partition drives RDMA
+operations; hypervisors never directly causes the movement of message data.
+
+Example Management Partition VMC Driver Interface
+=================================================
+This section provides an example for the Novalink implementation where a
+device driver is used to interface to the VMC device. This driver
+consists of a new device, for example /dev/lparvmc, which provides
+interfaces to open, close, read, write, and perform ioctl’s against the
+VMC device.
+
+VMC Interface Initialization
+The device driver is responsible for initializing the VMC when the driver
+is loaded. It first creates and initializes the CRQ. Next, an exchange of
+VMC capabilities is performed to indicate the code version and number of
+resources available in both the management partition and the hypervisor.
+Finally, the hypervisor requests that the management partition create an
+initial pool of VMC buffers, one buffer for each possible HMC connection,
+which will be used for Novalink session initialization. Prior to completion
+of this initialization sequence, the device returns EBUSY to open() calls.
+EIO is returned for all open() failures.
+
+Management Partition		Hypervisor
+		CRQ INIT
+---------------------------------------->
+	   CRQ INIT COMPLETE
+<----------------------------------------
+	      CAPABILITIES
+---------------------------------------->
+	 CAPABILITIES RESPONSE
+<----------------------------------------
+      ADD BUFFER (MHC IDX=0,1,..)	  _
+<----------------------------------------  |
+	  ADD BUFFER RESPONSE		   | - Perform # HMCs Iterations
+----------------------------------------> -
+
+VMC Interface Open
+After the basic VMC channel has been initialized, an HMC session level
+connection can be established. The application layer performs an open() to
+the VMC device and executes an ioctl() against it, indicating the HMC ID
+(32 bytes of data) for this session. If the VMC device is in an invalid
+state, EIO will be returned for the ioctl(). The device driver creates a
+new HMC session value (ranging from 1 to 255) and HMC index value (starting
+at index 0 and potentially ranging to 254 in future releases) for this HMC
+ID. The driver then does an RDMA of the HMC ID to the hypervisor, and then
+sends an Interface Open message to the hypervisor to establish the session
+over the VMC. After the hypervisor receives this information, it sends Add
+Buffer messages to the management partition to seed an initial pool of
+buffers for the new HMC connection. Finally, the hypervisor sends an
+Interface Open Response message, to indicate that it is ready for normal
+runtime messaging. The following illustrates this VMC flow:
+
+Management Partition             Hypervisor
+	      RDMA HMC ID
+---------------------------------------->
+	    Interface Open
+---------------------------------------->
+	      Add Buffer		  _
+<----------------------------------------  |
+	  Add Buffer Response		   | - Perform N Iterations
+----------------------------------------> -
+	Interface Open Response
+<----------------------------------------
+
+VMC Interface Runtime
+During normal runtime, the Novalink application and the hypervisor
+exchange HMC messages via the Signal VMC message and RDMA operations. When
+sending data to the hypervisor, the Novalink application performs a
+write() to the VMC device, and the driver RDMA’s the data to the hypervisor
+and then sends a Signal Message. If a write() is attempted before VMC
+device buffers have been made available by the hypervisor, or no buffers
+are currently available, EBUSY is returned in response to the write(). A
+write() will return EIO for all other errors, such as an invalid device
+state. When the hypervisor sends a message to the Novalink, the data is
+put into a VMC buffer and an Signal Message is sent to the VMC driver in
+the management partition. The driver RDMA’s the buffer into the partition
+and passes the data up to the appropriate Novalink application via a
+read() to the VMC device. The read() request blocks if there is no buffer
+available to read. The Novalink application may use select() to wait for
+the VMC device to become ready with data to read.
+
+Management Partition             Hypervisor
+		MSG RDMA
+---------------------------------------->
+		SIGNAL MSG
+---------------------------------------->
+		SIGNAL MSG
+<----------------------------------------
+		MSG RDMA
+<----------------------------------------
+
+VMC Interface Close
+HMC session level connections are closed by the management partition when
+the application layer performs a close() against the device. This action
+results in an Interface Close message flowing to the hypervisor, which
+causes the session to be terminated. The device driver must free any
+storage allocated for buffers for this HMC connection.
+
+Management Partition             Hypervisor
+	     INTERFACE CLOSE
+---------------------------------------->
+        INTERFACE CLOSE RESPONSE
+<----------------------------------------
+
+For more information on the documentation for CRQ Messages, VMC Messages,
+HMC interface Buffers, and signal messages please refer to the Linux on
+Power Architecture Platform Reference. Section F.
diff --git a/MAINTAINERS b/MAINTAINERS
index c7182d2..79969f9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6721,6 +6721,12 @@ L:	linux-scsi@vger.kernel.org
 S:	Supported
 F:	drivers/scsi/ibmvscsi/ibmvfc*
 
+IBM Power Virtual Management Channel Driver
+M:	Bryant G. Ly <bryantly@linux.vnet.ibm.com>
+M:	Steven Royer <seroyer@linux.vnet.ibm.com>
+S:	Supported
+F:	drivers/misc/ibmvmc.*
+
 IBM Power Virtual SCSI Device Drivers
 M:	Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
 L:	linux-scsi@vger.kernel.org
diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
index 2e2ddda..662c834 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -279,6 +279,7 @@
 #define H_GET_MPP_X		0x314
 #define H_SET_MODE		0x31C
 #define H_CLEAR_HPT		0x358
+#define H_REQUEST_VMC		0x360
 #define H_RESIZE_HPT_PREPARE	0x36C
 #define H_RESIZE_HPT_COMMIT	0x370
 #define H_REGISTER_PROC_TBL	0x37C
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 5d71300..3726eac 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -113,6 +113,20 @@ config IBM_ASM
 	  for information on the specific driver level and support statement
 	  for your IBM server.
 
+config IBMVMC
+	tristate "IBM Virtual Management Channel support"
+	depends on PPC_PSERIES
+	help
+	  This is the IBM POWER Virtual Management Channel
+
+	  This driver is to be used for the POWER Virtual
+	  Management Channel virtual adapter on the PowerVM
+	  platform. It provides both request/response and
+	  async message support through the /dev/ibmvmc node.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ibmvmc.
+
 config PHANTOM
 	tristate "Sensable PHANToM (PCI)"
 	depends on PCI
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 20be70c..af22bbc 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -4,6 +4,7 @@
 #
 
 obj-$(CONFIG_IBM_ASM)		+= ibmasm/
+obj-$(CONFIG_IBMVMC)		+= ibmvmc.o
 obj-$(CONFIG_AD525X_DPOT)	+= ad525x_dpot.o
 obj-$(CONFIG_AD525X_DPOT_I2C)	+= ad525x_dpot-i2c.o
 obj-$(CONFIG_AD525X_DPOT_SPI)	+= ad525x_dpot-spi.o
diff --git a/drivers/misc/ibmvmc.c b/drivers/misc/ibmvmc.c
new file mode 100644
index 0000000..ae9cea3
--- /dev/null
+++ b/drivers/misc/ibmvmc.c
@@ -0,0 +1,2415 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * IBM Power Systems Virtual Management Channel Support.
+ *
+ * Copyright (c) 2004, 2018 IBM Corp.
+ *   Dave Engebretsen engebret@us.ibm.com
+ *   Steven Royer seroyer@linux.vnet.ibm.com
+ *   Adam Reznechek adreznec@linux.vnet.ibm.com
+ *   Bryant G. Ly <bryantly@linux.vnet.ibm.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/major.h>
+#include <linux/string.h>
+#include <linux/fcntl.h>
+#include <linux/slab.h>
+#include <linux/poll.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/percpu.h>
+#include <linux/delay.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+#include <linux/miscdevice.h>
+#include <linux/sched/signal.h>
+
+#include <asm/byteorder.h>
+#include <asm/irq.h>
+#include <asm/vio.h>
+
+#include "ibmvmc.h"
+
+#define IBMVMC_DRIVER_VERSION "1.0"
+
+/*
+ * Static global variables
+ */
+static DECLARE_WAIT_QUEUE_HEAD(ibmvmc_read_wait);
+
+static const char ibmvmc_driver_name[] = "ibmvmc";
+
+static struct ibmvmc_struct ibmvmc;
+static struct ibmvmc_hmc hmcs[MAX_HMCS];
+static struct crq_server_adapter ibmvmc_adapter;
+
+static int ibmvmc_max_buf_pool_size = DEFAULT_BUF_POOL_SIZE;
+static int ibmvmc_max_hmcs = DEFAULT_HMCS;
+static int ibmvmc_max_mtu = DEFAULT_MTU;
+
+static inline long h_copy_rdma(s64 length, u64 sliobn, u64 slioba,
+			       u64 dliobn, u64 dlioba)
+{
+	long rc = 0;
+
+	/* Ensure all writes to source memory are visible before hcall */
+	dma_wmb();
+	pr_debug("ibmvmc: h_copy_rdma(0x%llx, 0x%llx, 0x%llx, 0x%llx, 0x%llx\n",
+		 length, sliobn, slioba, dliobn, dlioba);
+	rc = plpar_hcall_norets(H_COPY_RDMA, length, sliobn, slioba,
+				dliobn, dlioba);
+	pr_debug("ibmvmc: h_copy_rdma rc = 0x%lx\n", rc);
+
+	return rc;
+}
+
+static inline void h_free_crq(uint32_t unit_address)
+{
+	long rc = 0;
+
+	do {
+		if (H_IS_LONG_BUSY(rc))
+			msleep(get_longbusy_msecs(rc));
+
+		rc = plpar_hcall_norets(H_FREE_CRQ, unit_address);
+	} while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
+}
+
+/**
+ * h_request_vmc: - request a hypervisor virtual management channel device
+ * @vmc_index: drc index of the vmc device created
+ *
+ * Requests the hypervisor create a new virtual management channel device,
+ * allowing this partition to send hypervisor virtualization control
+ * commands.
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static inline long h_request_vmc(u32 *vmc_index)
+{
+	long rc = 0;
+	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
+
+	do {
+		if (H_IS_LONG_BUSY(rc))
+			msleep(get_longbusy_msecs(rc));
+
+		/* Call to request the VMC device from phyp */
+		rc = plpar_hcall(H_REQUEST_VMC, retbuf);
+		pr_debug("ibmvmc: %s rc = 0x%lx\n", __func__, rc);
+		*vmc_index = retbuf[0];
+	} while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
+
+	return rc;
+}
+
+/* routines for managing a command/response queue */
+/**
+ * ibmvmc_handle_event: - Interrupt handler for crq events
+ * @irq:        number of irq to handle, not used
+ * @dev_instance: crq_server_adapter that received interrupt
+ *
+ * Disables interrupts and schedules ibmvmc_task
+ *
+ * Always returns IRQ_HANDLED
+ */
+static irqreturn_t ibmvmc_handle_event(int irq, void *dev_instance)
+{
+	struct crq_server_adapter *adapter =
+		(struct crq_server_adapter *)dev_instance;
+
+	vio_disable_interrupts(to_vio_dev(adapter->dev));
+	tasklet_schedule(&adapter->work_task);
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * ibmvmc_release_crq_queue - Release CRQ Queue
+ *
+ * @adapter:	crq_server_adapter struct
+ *
+ * Return:
+ *	0 - Success
+ *	Non-Zero - Failure
+ */
+static void ibmvmc_release_crq_queue(struct crq_server_adapter *adapter)
+{
+	struct vio_dev *vdev = to_vio_dev(adapter->dev);
+	struct crq_queue *queue = &adapter->queue;
+
+	free_irq(vdev->irq, (void *)adapter);
+	tasklet_kill(&adapter->work_task);
+
+	if (adapter->reset_task)
+		kthread_stop(adapter->reset_task);
+
+	h_free_crq(vdev->unit_address);
+	dma_unmap_single(adapter->dev,
+			 queue->msg_token,
+			 queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);
+	free_page((unsigned long)queue->msgs);
+}
+
+/**
+ * ibmvmc_reset_crq_queue - Reset CRQ Queue
+ *
+ * @adapter:	crq_server_adapter struct
+ *
+ * This function calls h_free_crq and then calls H_REG_CRQ and does all the
+ * bookkeeping to get us back to where we can communicate.
+ *
+ * Return:
+ *	0 - Success
+ *	Non-Zero - Failure
+ */
+static int ibmvmc_reset_crq_queue(struct crq_server_adapter *adapter)
+{
+	struct vio_dev *vdev = to_vio_dev(adapter->dev);
+	struct crq_queue *queue = &adapter->queue;
+	int rc = 0;
+
+	/* Close the CRQ */
+	h_free_crq(vdev->unit_address);
+
+	/* Clean out the queue */
+	memset(queue->msgs, 0x00, PAGE_SIZE);
+	queue->cur = 0;
+
+	/* And re-open it again */
+	rc = plpar_hcall_norets(H_REG_CRQ,
+				vdev->unit_address,
+				queue->msg_token, PAGE_SIZE);
+	if (rc == 2)
+		/* Adapter is good, but other end is not ready */
+		dev_warn(adapter->dev, "Partner adapter not ready\n");
+	else if (rc != 0)
+		dev_err(adapter->dev, "couldn't register crq--rc 0x%x\n", rc);
+
+	return rc;
+}
+
+/**
+ * crq_queue_next_crq: - Returns the next entry in message queue
+ * @queue:      crq_queue to use
+ *
+ * Returns pointer to next entry in queue, or NULL if there are no new
+ * entried in the CRQ.
+ */
+static struct ibmvmc_crq_msg *crq_queue_next_crq(struct crq_queue *queue)
+{
+	struct ibmvmc_crq_msg *crq;
+	unsigned long flags;
+
+	spin_lock_irqsave(&queue->lock, flags);
+	crq = &queue->msgs[queue->cur];
+	if (crq->valid & 0x80) {
+		if (++queue->cur == queue->size)
+			queue->cur = 0;
+
+		/* Ensure the read of the valid bit occurs before reading any
+		 * other bits of the CRQ entry
+		 */
+		dma_rmb();
+	} else {
+		crq = NULL;
+	}
+
+	spin_unlock_irqrestore(&queue->lock, flags);
+
+	return crq;
+}
+
+/**
+ * ibmvmc_send_crq - Send CRQ
+ *
+ * @adapter:	crq_server_adapter struct
+ * @word1:	Word1 Data field
+ * @word2:	Word2 Data field
+ *
+ * Return:
+ *	0 - Success
+ *	Non-Zero - Failure
+ */
+static long ibmvmc_send_crq(struct crq_server_adapter *adapter,
+			    u64 word1, u64 word2)
+{
+	struct vio_dev *vdev = to_vio_dev(adapter->dev);
+	long rc;
+
+	dev_dbg(adapter->dev, "(0x%x, 0x%016llx, 0x%016llx)\n",
+		vdev->unit_address, word1, word2);
+
+	/*
+	 * Ensure the command buffer is flushed to memory before handing it
+	 * over to the other side to prevent it from fetching any stale data.
+	 */
+	dma_wmb();
+	rc = plpar_hcall_norets(H_SEND_CRQ, vdev->unit_address, word1, word2);
+	dev_dbg(adapter->dev, "rc = 0x%lx\n", rc);
+
+	return rc;
+}
+
+/**
+ * alloc_dma_buffer - Create DMA Buffer
+ *
+ * @vdev:	vio_dev struct
+ * @size:	Size field
+ * @dma_handle:	DMA address field
+ *
+ * Allocates memory for the command queue and maps remote memory into an
+ * ioba.
+ *
+ * Returns a pointer to the buffer
+ */
+static void *alloc_dma_buffer(struct vio_dev *vdev, size_t size,
+			      dma_addr_t *dma_handle)
+{
+	/* allocate memory */
+	void *buffer = kzalloc(size, GFP_KERNEL);
+
+	if (!buffer) {
+		*dma_handle = 0;
+		return NULL;
+	}
+
+	/* DMA map */
+	*dma_handle = dma_map_single(&vdev->dev, buffer, size,
+				     DMA_BIDIRECTIONAL);
+
+	if (dma_mapping_error(&vdev->dev, *dma_handle)) {
+		*dma_handle = 0;
+		kzfree(buffer);
+		return NULL;
+	}
+
+	return buffer;
+}
+
+/**
+ * free_dma_buffer - Free DMA Buffer
+ *
+ * @vdev:	vio_dev struct
+ * @size:	Size field
+ * @vaddr:	Address field
+ * @dma_handle:	DMA address field
+ *
+ * Releases memory for a command queue and unmaps mapped remote memory.
+ */
+static void free_dma_buffer(struct vio_dev *vdev, size_t size, void *vaddr,
+			    dma_addr_t dma_handle)
+{
+	/* DMA unmap */
+	dma_unmap_single(&vdev->dev, dma_handle, size, DMA_BIDIRECTIONAL);
+
+	/* deallocate memory */
+	kzfree(vaddr);
+}
+
+/**
+ * ibmvmc_get_valid_hmc_buffer - Retrieve Valid HMC Buffer
+ *
+ * @hmc_index:	HMC Index Field
+ *
+ * Return:
+ *	Pointer to ibmvmc_buffer
+ */
+static struct ibmvmc_buffer *ibmvmc_get_valid_hmc_buffer(u8 hmc_index)
+{
+	struct ibmvmc_buffer *buffer;
+	struct ibmvmc_buffer *ret_buf = NULL;
+	unsigned long i;
+
+	if (hmc_index > ibmvmc.max_hmc_index)
+		return NULL;
+
+	buffer = hmcs[hmc_index].buffer;
+
+	for (i = 0; i < ibmvmc_max_buf_pool_size; i++) {
+		if (buffer[i].valid && buffer[i].free &&
+		    buffer[i].owner == VMC_BUF_OWNER_ALPHA) {
+			buffer[i].free = 0;
+			ret_buf = &buffer[i];
+			break;
+		}
+	}
+
+	return ret_buf;
+}
+
+/**
+ * ibmvmc_get_free_hmc_buffer - Get Free HMC Buffer
+ *
+ * @adapter:	crq_server_adapter struct
+ * @hmc_index:	Hmc Index field
+ *
+ * Return:
+ *	Pointer to ibmvmc_buffer
+ */
+static struct ibmvmc_buffer *ibmvmc_get_free_hmc_buffer(struct crq_server_adapter *adapter,
+							u8 hmc_index)
+{
+	struct ibmvmc_buffer *buffer;
+	struct ibmvmc_buffer *ret_buf = NULL;
+	unsigned long i;
+
+	if (hmc_index > ibmvmc.max_hmc_index) {
+		dev_info(adapter->dev, "get_free_hmc_buffer: invalid hmc_index=0x%x\n",
+			 hmc_index);
+		return NULL;
+	}
+
+	buffer = hmcs[hmc_index].buffer;
+
+	for (i = 0; i < ibmvmc_max_buf_pool_size; i++) {
+		if (buffer[i].free &&
+		    buffer[i].owner == VMC_BUF_OWNER_ALPHA) {
+			buffer[i].free = 0;
+			ret_buf = &buffer[i];
+			break;
+		}
+	}
+
+	return ret_buf;
+}
+
+/**
+ * ibmvmc_free_hmc_buffer - Free an HMC Buffer
+ *
+ * @hmc:	ibmvmc_hmc struct
+ * @buffer:	ibmvmc_buffer struct
+ *
+ */
+static void ibmvmc_free_hmc_buffer(struct ibmvmc_hmc *hmc,
+				   struct ibmvmc_buffer *buffer)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&hmc->lock, flags);
+	buffer->free = 1;
+	spin_unlock_irqrestore(&hmc->lock, flags);
+}
+
+/**
+ * ibmvmc_count_hmc_buffers - Count HMC Buffers
+ *
+ * @hmc_index:	HMC Index field
+ * @valid:	Valid number of buffers field
+ * @free:	Free number of buffers field
+ *
+ */
+static void ibmvmc_count_hmc_buffers(u8 hmc_index, unsigned int *valid,
+				     unsigned int *free)
+{
+	struct ibmvmc_buffer *buffer;
+	unsigned long i;
+	unsigned long flags;
+
+	if (hmc_index > ibmvmc.max_hmc_index)
+		return;
+
+	if (!valid || !free)
+		return;
+
+	*valid = 0; *free = 0;
+
+	buffer = hmcs[hmc_index].buffer;
+	spin_lock_irqsave(&hmcs[hmc_index].lock, flags);
+
+	for (i = 0; i < ibmvmc_max_buf_pool_size; i++) {
+		if (buffer[i].valid) {
+			*valid = *valid + 1;
+			if (buffer[i].free)
+				*free = *free + 1;
+		}
+	}
+
+	spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+}
+
+/**
+ * ibmvmc_get_free_hmc - Get Free HMC
+ *
+ * Return:
+ *	Pointer to an available HMC Connection
+ *	Null otherwise
+ */
+static struct ibmvmc_hmc *ibmvmc_get_free_hmc(void)
+{
+	unsigned long i;
+	unsigned long flags;
+
+	/*
+	 * Find an available HMC connection.
+	 */
+	for (i = 0; i <= ibmvmc.max_hmc_index; i++) {
+		spin_lock_irqsave(&hmcs[i].lock, flags);
+		if (hmcs[i].state == ibmhmc_state_free) {
+			hmcs[i].index = i;
+			hmcs[i].state = ibmhmc_state_initial;
+			spin_unlock_irqrestore(&hmcs[i].lock, flags);
+			return &hmcs[i];
+		}
+		spin_unlock_irqrestore(&hmcs[i].lock, flags);
+	}
+
+	return NULL;
+}
+
+/**
+ * ibmvmc_return_hmc - Return an HMC Connection
+ *
+ * @hmc:		ibmvmc_hmc struct
+ * @release_readers:	Number of readers connected to session
+ *
+ * This function releases the HMC connections back into the pool.
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static int ibmvmc_return_hmc(struct ibmvmc_hmc *hmc, bool release_readers)
+{
+	struct ibmvmc_buffer *buffer;
+	struct crq_server_adapter *adapter;
+	struct vio_dev *vdev;
+	unsigned long i;
+	unsigned long flags;
+
+	if (!hmc || !hmc->adapter)
+		return -EIO;
+
+	if (release_readers) {
+		if (hmc->file_session) {
+			struct ibmvmc_file_session *session = hmc->file_session;
+
+			session->valid = 0;
+			wake_up_interruptible(&ibmvmc_read_wait);
+		}
+	}
+
+	adapter = hmc->adapter;
+	vdev = to_vio_dev(adapter->dev);
+
+	spin_lock_irqsave(&hmc->lock, flags);
+	hmc->index = 0;
+	hmc->state = ibmhmc_state_free;
+	hmc->queue_head = 0;
+	hmc->queue_tail = 0;
+	buffer = hmc->buffer;
+	for (i = 0; i < ibmvmc_max_buf_pool_size; i++) {
+		if (buffer[i].valid) {
+			free_dma_buffer(vdev,
+					ibmvmc.max_mtu,
+					buffer[i].real_addr_local,
+					buffer[i].dma_addr_local);
+			dev_dbg(adapter->dev, "Forgot buffer id 0x%lx\n", i);
+		}
+		memset(&buffer[i], 0, sizeof(struct ibmvmc_buffer));
+
+		hmc->queue_outbound_msgs[i] = VMC_INVALID_BUFFER_ID;
+	}
+
+	spin_unlock_irqrestore(&hmc->lock, flags);
+
+	return 0;
+}
+
+/**
+ * ibmvmc_send_open - Interface Open
+ * @buffer: Pointer to ibmvmc_buffer struct
+ * @hmc: Pointer to ibmvmc_hmc struct
+ *
+ * This command is sent by the management partition as the result of a
+ * management partition device request. It causes the hypervisor to
+ * prepare a set of data buffers for the Novalink connection indicated HMC idx.
+ * A unique HMC Idx would be used if multiple management applications running
+ * concurrently were desired. Before responding to this command, the
+ * hypervisor must provide the management partition with at least one of these
+ * new buffers via the Add Buffer. This indicates whether the messages are
+ * inbound or outbound from the hypervisor.
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static int ibmvmc_send_open(struct ibmvmc_buffer *buffer,
+			    struct ibmvmc_hmc *hmc)
+{
+	struct ibmvmc_crq_msg crq_msg;
+	struct crq_server_adapter *adapter;
+	__be64 *crq_as_u64 = (__be64 *)&crq_msg;
+	int rc = 0;
+
+	if (!hmc || !hmc->adapter)
+		return -EIO;
+
+	adapter = hmc->adapter;
+
+	dev_dbg(adapter->dev, "send_open: 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
+		(unsigned long)buffer->size, (unsigned long)adapter->liobn,
+		(unsigned long)buffer->dma_addr_local,
+		(unsigned long)adapter->riobn,
+		(unsigned long)buffer->dma_addr_remote);
+
+	rc = h_copy_rdma(buffer->size,
+			 adapter->liobn,
+			 buffer->dma_addr_local,
+			 adapter->riobn,
+			 buffer->dma_addr_remote);
+	if (rc) {
+		dev_err(adapter->dev, "Error: In send_open, h_copy_rdma rc 0x%x\n",
+			rc);
+		return -EIO;
+	}
+
+	hmc->state = ibmhmc_state_opening;
+
+	crq_msg.valid = 0x80;
+	crq_msg.type = VMC_MSG_OPEN;
+	crq_msg.status = 0;
+	crq_msg.var1.rsvd = 0;
+	crq_msg.hmc_session = hmc->session;
+	crq_msg.hmc_index = hmc->index;
+	crq_msg.var2.buffer_id = cpu_to_be16(buffer->id);
+	crq_msg.rsvd = 0;
+	crq_msg.var3.rsvd = 0;
+
+	ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+			be64_to_cpu(crq_as_u64[1]));
+
+	return rc;
+}
+
+/**
+ * ibmvmc_send_close - Interface Close
+ * @hmc: Pointer to ibmvmc_hmc struct
+ *
+ * This command is sent by the management partition to terminate an Novalink to
+ * hypervisor connection. When this command is sent, the management
+ * partition has quiesced all I/O operations to all buffers associated with
+ * this Novalink connection, and has freed any storage for these buffers.
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static int ibmvmc_send_close(struct ibmvmc_hmc *hmc)
+{
+	struct ibmvmc_crq_msg crq_msg;
+	struct crq_server_adapter *adapter;
+	__be64 *crq_as_u64 = (__be64 *)&crq_msg;
+	int rc = 0;
+
+	if (!hmc || !hmc->adapter)
+		return -EIO;
+
+	adapter = hmc->adapter;
+
+	dev_info(adapter->dev, "CRQ send: close\n");
+
+	crq_msg.valid = 0x80;
+	crq_msg.type = VMC_MSG_CLOSE;
+	crq_msg.status = 0;
+	crq_msg.var1.rsvd = 0;
+	crq_msg.hmc_session = hmc->session;
+	crq_msg.hmc_index = hmc->index;
+	crq_msg.var2.rsvd = 0;
+	crq_msg.rsvd = 0;
+	crq_msg.var3.rsvd = 0;
+
+	ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+			be64_to_cpu(crq_as_u64[1]));
+
+	return rc;
+}
+
+/**
+ * ibmvmc_send_capabilities - Send VMC Capabilities
+ *
+ * @adapter:	crq_server_adapter struct
+ *
+ * The capabilities message is an administrative message sent after the CRQ
+ * initialization sequence of messages and is used to exchange VMC capabilities
+ * between the management partition and the hypervisor. The management
+ * partition must send this message and the hypervisor must respond with VMC
+ * capabilities Response message before HMC interface message can begin. Any
+ * HMC interface messages received before the exchange of capabilities has
+ * complete are dropped.
+ *
+ * Return:
+ *	0 - Success
+ */
+static int ibmvmc_send_capabilities(struct crq_server_adapter *adapter)
+{
+	struct ibmvmc_admin_crq_msg crq_msg;
+	__be64 *crq_as_u64 = (__be64 *)&crq_msg;
+
+	dev_dbg(adapter->dev, "ibmvmc: CRQ send: capabilities\n");
+	crq_msg.valid = 0x80;
+	crq_msg.type = VMC_MSG_CAP;
+	crq_msg.status = 0;
+	crq_msg.rsvd[0] = 0;
+	crq_msg.rsvd[1] = 0;
+	crq_msg.max_hmc = ibmvmc_max_hmcs;
+	crq_msg.max_mtu = cpu_to_be32(ibmvmc_max_mtu);
+	crq_msg.pool_size = cpu_to_be16(ibmvmc_max_buf_pool_size);
+	crq_msg.crq_size = cpu_to_be16(adapter->queue.size);
+	crq_msg.version = cpu_to_be16(IBMVMC_PROTOCOL_VERSION);
+
+	ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+			be64_to_cpu(crq_as_u64[1]));
+
+	ibmvmc.state = ibmvmc_state_capabilities;
+
+	return 0;
+}
+
+/**
+ * ibmvmc_send_add_buffer_resp - Add Buffer Response
+ *
+ * @adapter:	crq_server_adapter struct
+ * @status:	Status field
+ * @hmc_session: HMC Session field
+ * @hmc_index:	HMC Index field
+ * @buffer_id:	Buffer Id field
+ *
+ * This command is sent by the management partition to the hypervisor in
+ * response to the Add Buffer message. The Status field indicates the result of
+ * the command.
+ *
+ * Return:
+ *	0 - Success
+ */
+static int ibmvmc_send_add_buffer_resp(struct crq_server_adapter *adapter,
+				       u8 status, u8 hmc_session,
+				       u8 hmc_index, u16 buffer_id)
+{
+	struct ibmvmc_crq_msg crq_msg;
+	__be64 *crq_as_u64 = (__be64 *)&crq_msg;
+
+	dev_dbg(adapter->dev, "CRQ send: add_buffer_resp\n");
+	crq_msg.valid = 0x80;
+	crq_msg.type = VMC_MSG_ADD_BUF_RESP;
+	crq_msg.status = status;
+	crq_msg.var1.rsvd = 0;
+	crq_msg.hmc_session = hmc_session;
+	crq_msg.hmc_index = hmc_index;
+	crq_msg.var2.buffer_id = cpu_to_be16(buffer_id);
+	crq_msg.rsvd = 0;
+	crq_msg.var3.rsvd = 0;
+
+	ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+			be64_to_cpu(crq_as_u64[1]));
+
+	return 0;
+}
+
+/**
+ * ibmvmc_send_rem_buffer_resp - Remove Buffer Response
+ *
+ * @adapter:	crq_server_adapter struct
+ * @status:	Status field
+ * @hmc_session: HMC Session field
+ * @hmc_index:	HMC Index field
+ * @buffer_id:	Buffer Id field
+ *
+ * This command is sent by the management partition to the hypervisor in
+ * response to the Remove Buffer message. The Buffer ID field indicates
+ * which buffer the management partition selected to remove. The Status
+ * field indicates the result of the command.
+ *
+ * Return:
+ *	0 - Success
+ */
+static int ibmvmc_send_rem_buffer_resp(struct crq_server_adapter *adapter,
+				       u8 status, u8 hmc_session,
+				       u8 hmc_index, u16 buffer_id)
+{
+	struct ibmvmc_crq_msg crq_msg;
+	__be64 *crq_as_u64 = (__be64 *)&crq_msg;
+
+	dev_dbg(adapter->dev, "CRQ send: rem_buffer_resp\n");
+	crq_msg.valid = 0x80;
+	crq_msg.type = VMC_MSG_REM_BUF_RESP;
+	crq_msg.status = status;
+	crq_msg.var1.rsvd = 0;
+	crq_msg.hmc_session = hmc_session;
+	crq_msg.hmc_index = hmc_index;
+	crq_msg.var2.buffer_id = cpu_to_be16(buffer_id);
+	crq_msg.rsvd = 0;
+	crq_msg.var3.rsvd = 0;
+
+	ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+			be64_to_cpu(crq_as_u64[1]));
+
+	return 0;
+}
+
+/**
+ * ibmvmc_send_msg - Signal Message
+ *
+ * @adapter:	crq_server_adapter struct
+ * @buffer:	ibmvmc_buffer struct
+ * @hmc:	ibmvmc_hmc struct
+ * @msg_length:	message length field
+ *
+ * This command is sent between the management partition and the hypervisor
+ * in order to signal the arrival of an HMC protocol message. The command
+ * can be sent by both the management partition and the hypervisor. It is
+ * used for all traffic between the Novalink application and the hypervisor,
+ * regardless of who initiated the communication.
+ *
+ * There is no response to this message.
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static int ibmvmc_send_msg(struct crq_server_adapter *adapter,
+			   struct ibmvmc_buffer *buffer,
+			   struct ibmvmc_hmc *hmc, int msg_len)
+{
+	struct ibmvmc_crq_msg crq_msg;
+	__be64 *crq_as_u64 = (__be64 *)&crq_msg;
+	int rc = 0;
+
+	dev_dbg(adapter->dev, "CRQ send: rdma to HV\n");
+	rc = h_copy_rdma(msg_len,
+			 adapter->liobn,
+			 buffer->dma_addr_local,
+			 adapter->riobn,
+			 buffer->dma_addr_remote);
+	if (rc) {
+		dev_err(adapter->dev, "Error in send_msg, h_copy_rdma rc 0x%x\n",
+			rc);
+		return rc;
+	}
+
+	crq_msg.valid = 0x80;
+	crq_msg.type = VMC_MSG_SIGNAL;
+	crq_msg.status = 0;
+	crq_msg.var1.rsvd = 0;
+	crq_msg.hmc_session = hmc->session;
+	crq_msg.hmc_index = hmc->index;
+	crq_msg.var2.buffer_id = cpu_to_be16(buffer->id);
+	crq_msg.var3.msg_len = cpu_to_be32(msg_len);
+	dev_dbg(adapter->dev, "CRQ send: msg to HV 0x%llx 0x%llx\n",
+		be64_to_cpu(crq_as_u64[0]), be64_to_cpu(crq_as_u64[1]));
+
+	buffer->owner = VMC_BUF_OWNER_HV;
+	ibmvmc_send_crq(adapter, be64_to_cpu(crq_as_u64[0]),
+			be64_to_cpu(crq_as_u64[1]));
+
+	return rc;
+}
+
+/**
+ * ibmvmc_open - Open Session
+ *
+ * @inode:	inode struct
+ * @file:	file struct
+ *
+ * Return:
+ *	0 - Success
+ */
+static int ibmvmc_open(struct inode *inode, struct file *file)
+{
+	struct ibmvmc_file_session *session;
+	int rc = 0;
+
+	pr_debug("%s: inode = 0x%lx, file = 0x%lx, state = 0x%x\n", __func__,
+		 (unsigned long)inode, (unsigned long)file,
+		 ibmvmc.state);
+
+	session = kzalloc(sizeof(*session), GFP_KERNEL);
+	session->file = file;
+	file->private_data = session;
+
+	return rc;
+}
+
+/**
+ * ibmvmc_close - Close Session
+ *
+ * @inode:	inode struct
+ * @file:	file struct
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static int ibmvmc_close(struct inode *inode, struct file *file)
+{
+	struct ibmvmc_file_session *session;
+	struct ibmvmc_hmc *hmc;
+	int rc = 0;
+	unsigned long flags;
+
+	pr_debug("%s: file = 0x%lx, state = 0x%x\n", __func__,
+		 (unsigned long)file, ibmvmc.state);
+
+	session = file->private_data;
+	if (!session)
+		return -EIO;
+
+	hmc = session->hmc;
+	if (hmc) {
+		if (!hmc->adapter)
+			return -EIO;
+
+		if (ibmvmc.state == ibmvmc_state_failed) {
+			dev_warn(hmc->adapter->dev, "close: state_failed\n");
+			return -EIO;
+		}
+
+		spin_lock_irqsave(&hmc->lock, flags);
+		if (hmc->state >= ibmhmc_state_opening) {
+			rc = ibmvmc_send_close(hmc);
+			if (rc)
+				dev_warn(hmc->adapter->dev, "close: send_close failed.\n");
+		}
+		spin_unlock_irqrestore(&hmc->lock, flags);
+	}
+
+	kzfree(session);
+
+	return rc;
+}
+
+/**
+ * ibmvmc_read - Read
+ *
+ * @file:	file struct
+ * @buf:	Character buffer
+ * @nbytes:	Size in bytes
+ * @ppos:	Offset
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static ssize_t ibmvmc_read(struct file *file, char *buf, size_t nbytes,
+			   loff_t *ppos)
+{
+	struct ibmvmc_file_session *session;
+	struct ibmvmc_hmc *hmc;
+	struct crq_server_adapter *adapter;
+	struct ibmvmc_buffer *buffer;
+	ssize_t n;
+	ssize_t retval = 0;
+	unsigned long flags;
+	DEFINE_WAIT(wait);
+
+	pr_debug("ibmvmc: read: file = 0x%lx, buf = 0x%lx, nbytes = 0x%lx\n",
+		 (unsigned long)file, (unsigned long)buf,
+		 (unsigned long)nbytes);
+
+	if (nbytes == 0)
+		return 0;
+
+	if (nbytes > ibmvmc.max_mtu) {
+		pr_warn("ibmvmc: read: nbytes invalid 0x%x\n",
+			(unsigned int)nbytes);
+		return -EINVAL;
+	}
+
+	session = file->private_data;
+	if (!session) {
+		pr_warn("ibmvmc: read: no session\n");
+		return -EIO;
+	}
+
+	hmc = session->hmc;
+	if (!hmc) {
+		pr_warn("ibmvmc: read: no hmc\n");
+		return -EIO;
+	}
+
+	adapter = hmc->adapter;
+	if (!adapter) {
+		pr_warn("ibmvmc: read: no adapter\n");
+		return -EIO;
+	}
+
+	do {
+		prepare_to_wait(&ibmvmc_read_wait, &wait, TASK_INTERRUPTIBLE);
+
+		spin_lock_irqsave(&hmc->lock, flags);
+		if (hmc->queue_tail != hmc->queue_head)
+			/* Data is available */
+			break;
+
+		spin_unlock_irqrestore(&hmc->lock, flags);
+
+		if (!session->valid) {
+			retval = -EBADFD;
+			goto out;
+		}
+		if (file->f_flags & O_NONBLOCK) {
+			retval = -EAGAIN;
+			goto out;
+		}
+
+		schedule();
+
+		if (signal_pending(current)) {
+			retval = -ERESTARTSYS;
+			goto out;
+		}
+	} while (1);
+
+	buffer = &(hmc->buffer[hmc->queue_outbound_msgs[hmc->queue_tail]]);
+	hmc->queue_tail++;
+	if (hmc->queue_tail == ibmvmc_max_buf_pool_size)
+		hmc->queue_tail = 0;
+	spin_unlock_irqrestore(&hmc->lock, flags);
+
+	nbytes = min_t(size_t, nbytes, buffer->msg_len);
+	n = copy_to_user((void *)buf, buffer->real_addr_local, nbytes);
+	dev_dbg(adapter->dev, "read: copy to user nbytes = 0x%lx.\n", nbytes);
+	ibmvmc_free_hmc_buffer(hmc, buffer);
+	retval = nbytes;
+
+	if (n) {
+		dev_warn(adapter->dev, "read: copy to user failed.\n");
+		retval = -EFAULT;
+	}
+
+ out:
+	finish_wait(&ibmvmc_read_wait, &wait);
+	dev_dbg(adapter->dev, "read: out %ld\n", retval);
+	return retval;
+}
+
+/**
+ * ibmvmc_poll - Poll
+ *
+ * @file:	file struct
+ * @wait:	Poll Table
+ *
+ * Return:
+ *	poll.h return values
+ */
+static unsigned int ibmvmc_poll(struct file *file, poll_table *wait)
+{
+	struct ibmvmc_file_session *session;
+	struct ibmvmc_hmc *hmc;
+	unsigned int mask = 0;
+
+	session = file->private_data;
+	if (!session)
+		return 0;
+
+	hmc = session->hmc;
+	if (!hmc)
+		return 0;
+
+	poll_wait(file, &ibmvmc_read_wait, wait);
+
+	if (hmc->queue_head != hmc->queue_tail)
+		mask |= POLLIN | POLLRDNORM;
+
+	return mask;
+}
+
+/**
+ * ibmvmc_write - Write
+ *
+ * @file:	file struct
+ * @buf:	Character buffer
+ * @count:	Count field
+ * @ppos:	Offset
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static ssize_t ibmvmc_write(struct file *file, const char *buffer,
+			    size_t count, loff_t *ppos)
+{
+	struct ibmvmc_buffer *vmc_buffer;
+	struct ibmvmc_file_session *session;
+	struct crq_server_adapter *adapter;
+	struct ibmvmc_hmc *hmc;
+	unsigned char *buf;
+	unsigned long flags;
+	size_t bytes;
+	const char *p = buffer;
+	size_t c = count;
+	int ret = 0;
+
+	session = file->private_data;
+	if (!session)
+		return -EIO;
+
+	hmc = session->hmc;
+	if (!hmc)
+		return -EIO;
+
+	spin_lock_irqsave(&hmc->lock, flags);
+	if (hmc->state == ibmhmc_state_free) {
+		/* HMC connection is not valid (possibly was reset under us). */
+		ret = -EIO;
+		goto out;
+	}
+
+	adapter = hmc->adapter;
+	if (!adapter) {
+		ret = -EIO;
+		goto out;
+	}
+
+	if (count > ibmvmc.max_mtu) {
+		dev_warn(adapter->dev, "invalid buffer size 0x%lx\n",
+			 (unsigned long)count);
+		ret = -EIO;
+		goto out;
+	}
+
+	/* Waiting for the open resp message to the ioctl(1) - retry */
+	if (hmc->state == ibmhmc_state_opening) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	/* Make sure the ioctl() was called & the open msg sent, and that
+	 * the HMC connection has not failed.
+	 */
+	if (hmc->state != ibmhmc_state_ready) {
+		ret = -EIO;
+		goto out;
+	}
+
+	vmc_buffer = ibmvmc_get_valid_hmc_buffer(hmc->index);
+	if (!vmc_buffer) {
+		/* No buffer available for the msg send, or we have not yet
+		 * completed the open/open_resp sequence.  Retry until this is
+		 * complete.
+		 */
+		ret = -EBUSY;
+		goto out;
+	}
+	if (!vmc_buffer->real_addr_local) {
+		dev_err(adapter->dev, "no buffer storage assigned\n");
+		ret = -EIO;
+		goto out;
+	}
+	buf = vmc_buffer->real_addr_local;
+
+	while (c > 0) {
+		bytes = min_t(size_t, c, vmc_buffer->size);
+
+		bytes -= copy_from_user(buf, p, bytes);
+		if (!bytes) {
+			ret = -EFAULT;
+			goto out;
+		}
+		c -= bytes;
+		p += bytes;
+	}
+	if (p == buffer)
+		goto out;
+
+	file->f_path.dentry->d_inode->i_mtime = current_time(file_inode(file));
+	mark_inode_dirty(file->f_path.dentry->d_inode);
+
+	dev_dbg(adapter->dev, "write: file = 0x%lx, count = 0x%lx\n",
+		(unsigned long)file, (unsigned long)count);
+
+	ibmvmc_send_msg(adapter, vmc_buffer, hmc, count);
+	ret = p - buffer;
+ out:
+	spin_unlock_irqrestore(&hmc->lock, flags);
+	return (ssize_t)(ret);
+}
+
+/**
+ * ibmvmc_setup_hmc - Setup the HMC
+ *
+ * @session:	ibmvmc_file_session struct
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static long ibmvmc_setup_hmc(struct ibmvmc_file_session *session)
+{
+	struct ibmvmc_hmc *hmc;
+	unsigned int valid, free, index;
+
+	if (ibmvmc.state == ibmvmc_state_failed) {
+		pr_warn("ibmvmc: Reserve HMC: state_failed\n");
+		return -EIO;
+	}
+
+	if (ibmvmc.state < ibmvmc_state_ready) {
+		pr_warn("ibmvmc: Reserve HMC: not state_ready\n");
+		return -EAGAIN;
+	}
+
+	/* Device is busy until capabilities have been exchanged and we
+	 * have a generic buffer for each possible HMC connection.
+	 */
+	for (index = 0; index <= ibmvmc.max_hmc_index; index++) {
+		valid = 0;
+		ibmvmc_count_hmc_buffers(index, &valid, &free);
+		if (valid == 0) {
+			pr_warn("ibmvmc: buffers not ready for index %d\n",
+				index);
+			return -ENOBUFS;
+		}
+	}
+
+	/* Get an hmc object, and transition to ibmhmc_state_initial */
+	hmc = ibmvmc_get_free_hmc();
+	if (!hmc) {
+		pr_warn("%s: free hmc not found\n", __func__);
+		return -EBUSY;
+	}
+
+	hmc->session = hmc->session + 1;
+	if (hmc->session == 0xff)
+		hmc->session = 1;
+
+	session->hmc = hmc;
+	hmc->adapter = &ibmvmc_adapter;
+	hmc->file_session = session;
+	session->valid = 1;
+
+	return 0;
+}
+
+/**
+ * ibmvmc_ioctl_sethmcid - IOCTL Set HMC ID
+ *
+ * @session:	ibmvmc_file_session struct
+ * @new_hmc_id:	HMC id field
+ *
+ * IOCTL command to setup the hmc id
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static long ibmvmc_ioctl_sethmcid(struct ibmvmc_file_session *session,
+				  unsigned char __user *new_hmc_id)
+{
+	struct ibmvmc_hmc *hmc;
+	struct ibmvmc_buffer *buffer;
+	size_t bytes;
+	char print_buffer[HMC_ID_LEN + 1];
+	unsigned long flags;
+	long rc = 0;
+
+	/* Reserve HMC session */
+	hmc = session->hmc;
+	if (!hmc) {
+		rc = ibmvmc_setup_hmc(session);
+		if (rc)
+			return rc;
+
+		hmc = session->hmc;
+		if (!hmc) {
+			pr_err("ibmvmc: setup_hmc success but no hmc\n");
+			return -EIO;
+		}
+	}
+
+	if (hmc->state != ibmhmc_state_initial) {
+		pr_warn("ibmvmc: sethmcid: invalid state to send open 0x%x\n",
+			hmc->state);
+		return -EIO;
+	}
+
+	bytes = copy_from_user(hmc->hmc_id, new_hmc_id, HMC_ID_LEN);
+	if (bytes)
+		return -EFAULT;
+
+	/* Send Open Session command */
+	spin_lock_irqsave(&hmc->lock, flags);
+	buffer = ibmvmc_get_valid_hmc_buffer(hmc->index);
+	spin_unlock_irqrestore(&hmc->lock, flags);
+
+	if (!buffer || !buffer->real_addr_local) {
+		pr_warn("ibmvmc: sethmcid: no buffer available\n");
+		return -EIO;
+	}
+
+	/* Make sure buffer is NULL terminated before trying to print it */
+	memset(print_buffer, 0, HMC_ID_LEN + 1);
+	strncpy(print_buffer, hmc->hmc_id, HMC_ID_LEN);
+	pr_info("ibmvmc: sethmcid: Set HMC ID: \"%s\"\n", print_buffer);
+
+	memcpy(buffer->real_addr_local, hmc->hmc_id, HMC_ID_LEN);
+	/* RDMA over ID, send open msg, change state to ibmhmc_state_opening */
+	rc = ibmvmc_send_open(buffer, hmc);
+
+	return rc;
+}
+
+/**
+ * ibmvmc_ioctl_query - IOCTL Query
+ *
+ * @session:	ibmvmc_file_session struct
+ * @ret_struct:	ibmvmc_query_struct
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static long ibmvmc_ioctl_query(struct ibmvmc_file_session *session,
+			       struct ibmvmc_query_struct __user *ret_struct)
+{
+	struct ibmvmc_query_struct query_struct;
+	size_t bytes;
+
+	memset(&query_struct, 0, sizeof(query_struct));
+	query_struct.have_vmc = (ibmvmc.state > ibmvmc_state_initial);
+	query_struct.state = ibmvmc.state;
+	query_struct.vmc_drc_index = ibmvmc.vmc_drc_index;
+
+	bytes = copy_to_user(ret_struct, &query_struct,
+			     sizeof(query_struct));
+	if (bytes)
+		return -EFAULT;
+
+	return 0;
+}
+
+/**
+ * ibmvmc_ioctl_requestvmc - IOCTL Request VMC
+ *
+ * @session:	ibmvmc_file_session struct
+ * @ret_vmc_index:	VMC Index
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static long ibmvmc_ioctl_requestvmc(struct ibmvmc_file_session *session,
+				    u32 __user *ret_vmc_index)
+{
+	/* TODO: (adreznec) Add locking to control multiple process access */
+	size_t bytes;
+	long rc;
+	u32 vmc_drc_index;
+
+	/* Call to request the VMC device from phyp*/
+	rc = h_request_vmc(&vmc_drc_index);
+	pr_debug("ibmvmc: requestvmc: H_REQUEST_VMC rc = 0x%lx\n", rc);
+
+	if (rc == H_SUCCESS) {
+		rc = 0;
+	} else if (rc == H_FUNCTION) {
+		pr_err("ibmvmc: requestvmc: h_request_vmc not supported\n");
+		return -EPERM;
+	} else if (rc == H_AUTHORITY) {
+		pr_err("ibmvmc: requestvmc: hypervisor denied vmc request\n");
+		return -EPERM;
+	} else if (rc == H_HARDWARE) {
+		pr_err("ibmvmc: requestvmc: hypervisor hardware fault\n");
+		return -EIO;
+	} else if (rc == H_RESOURCE) {
+		pr_err("ibmvmc: requestvmc: vmc resource unavailable\n");
+		return -ENODEV;
+	} else if (rc == H_NOT_AVAILABLE) {
+		pr_err("ibmvmc: requestvmc: system cannot be vmc managed\n");
+		return -EPERM;
+	} else if (rc == H_PARAMETER) {
+		pr_err("ibmvmc: requestvmc: invalid parameter\n");
+		return -EINVAL;
+	}
+
+	/* Success, set the vmc index in global struct */
+	ibmvmc.vmc_drc_index = vmc_drc_index;
+
+	bytes = copy_to_user(ret_vmc_index, &vmc_drc_index,
+			     sizeof(*ret_vmc_index));
+	if (bytes) {
+		pr_warn("ibmvmc: requestvmc: copy to user failed.\n");
+		return -EFAULT;
+	}
+	return rc;
+}
+
+/**
+ * ibmvmc_ioctl - IOCTL
+ *
+ * @session:	ibmvmc_file_session struct
+ * @cmd:	cmd field
+ * @arg:	Argument field
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static long ibmvmc_ioctl(struct file *file,
+			 unsigned int cmd, unsigned long arg)
+{
+	struct ibmvmc_file_session *session = file->private_data;
+
+	pr_debug("ibmvmc: ioctl file=0x%lx, cmd=0x%x, arg=0x%lx, ses=0x%lx\n",
+		 (unsigned long)file, cmd, arg,
+		 (unsigned long)session);
+
+	if (!session) {
+		pr_warn("ibmvmc: ioctl: no session\n");
+		return -EIO;
+	}
+
+	switch (cmd) {
+	case VMC_IOCTL_SETHMCID:
+		return ibmvmc_ioctl_sethmcid(session,
+			(unsigned char __user *)arg);
+	case VMC_IOCTL_QUERY:
+		return ibmvmc_ioctl_query(session,
+			(struct ibmvmc_query_struct __user *)arg);
+	case VMC_IOCTL_REQUESTVMC:
+		return ibmvmc_ioctl_requestvmc(session,
+			(unsigned int __user *)arg);
+	default:
+		pr_warn("ibmvmc: unknown ioctl 0x%x\n", cmd);
+		return -EINVAL;
+	}
+}
+
+static const struct file_operations ibmvmc_fops = {
+	.owner		= THIS_MODULE,
+	.read		= ibmvmc_read,
+	.write		= ibmvmc_write,
+	.poll		= ibmvmc_poll,
+	.unlocked_ioctl	= ibmvmc_ioctl,
+	.open           = ibmvmc_open,
+	.release        = ibmvmc_close,
+};
+
+/**
+ * ibmvmc_add_buffer - Add Buffer
+ *
+ * @adapter: crq_server_adapter struct
+ * @crq:	ibmvmc_crq_msg struct
+ *
+ * This message transfers a buffer from hypervisor ownership to management
+ * partition ownership. The LIOBA is obtained from the virtual TCE table
+ * associated with the hypervisor side of the VMC device, and points to a
+ * buffer of size MTU (as established in the capabilities exchange).
+ *
+ * Typical flow for ading buffers:
+ * 1. A new Novalink connection is opened by the management partition.
+ * 2. The hypervisor assigns new buffers for the traffic associated with
+ *	that connection.
+ * 3. The hypervisor sends VMC Add Buffer messages to the management
+ *	partition, informing it of the new buffers.
+ * 4. The hypervisor sends an HMC protocol message (to the Novalink application)
+ *	notifying it of the new buffers. This informs the application that
+ *	it has buffers available for sending HMC commands.
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static int ibmvmc_add_buffer(struct crq_server_adapter *adapter,
+			     struct ibmvmc_crq_msg *crq)
+{
+	struct ibmvmc_buffer *buffer;
+	u8 hmc_index;
+	u8 hmc_session;
+	u16 buffer_id;
+	unsigned long flags;
+	int rc = 0;
+
+	if (!crq)
+		return -1;
+
+	hmc_session = crq->hmc_session;
+	hmc_index = crq->hmc_index;
+	buffer_id = be16_to_cpu(crq->var2.buffer_id);
+
+	if (hmc_index > ibmvmc.max_hmc_index) {
+		dev_err(adapter->dev, "add_buffer: invalid hmc_index = 0x%x\n",
+			hmc_index);
+		ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INVALID_HMC_INDEX,
+					    hmc_session, hmc_index, buffer_id);
+		return -1;
+	}
+
+	if (buffer_id >= ibmvmc.max_buffer_pool_size) {
+		dev_err(adapter->dev, "add_buffer: invalid buffer_id = 0x%x\n",
+			buffer_id);
+		ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INVALID_BUFFER_ID,
+					    hmc_session, hmc_index, buffer_id);
+		return -1;
+	}
+
+	spin_lock_irqsave(&hmcs[hmc_index].lock, flags);
+	buffer = &hmcs[hmc_index].buffer[buffer_id];
+
+	if (buffer->real_addr_local || buffer->dma_addr_local) {
+		dev_warn(adapter->dev, "add_buffer: already allocated id = 0x%lx\n",
+			 (unsigned long)buffer_id);
+		spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+		ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INVALID_BUFFER_ID,
+					    hmc_session, hmc_index, buffer_id);
+		return -1;
+	}
+
+	buffer->real_addr_local = alloc_dma_buffer(to_vio_dev(adapter->dev),
+						   ibmvmc.max_mtu,
+						   &buffer->dma_addr_local);
+
+	if (!buffer->real_addr_local) {
+		dev_err(adapter->dev, "add_buffer: alloc_dma_buffer failed.\n");
+		spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+		ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INTERFACE_FAILURE,
+					    hmc_session, hmc_index, buffer_id);
+		return -1;
+	}
+
+	buffer->dma_addr_remote = be32_to_cpu(crq->var3.lioba);
+	buffer->size = ibmvmc.max_mtu;
+	buffer->owner = crq->var1.owner;
+	buffer->free = 1;
+	/* Must ensure valid==1 is observable only after all other fields are */
+	dma_wmb();
+	buffer->valid = 1;
+	buffer->id = buffer_id;
+
+	dev_dbg(adapter->dev, "add_buffer: successfully added a buffer:\n");
+	dev_dbg(adapter->dev, "   index: %d, session: %d, buffer: 0x%x, owner: %d\n",
+		hmc_index, hmc_session, buffer_id, buffer->owner);
+	dev_dbg(adapter->dev, "   local: 0x%x, remote: 0x%x\n",
+		(u32)buffer->dma_addr_local,
+		(u32)buffer->dma_addr_remote);
+	spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+
+	ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_SUCCESS, hmc_session,
+				    hmc_index, buffer_id);
+
+	return rc;
+}
+
+/**
+ * ibmvmc_rem_buffer - Remove Buffer
+ *
+ * @adapter: crq_server_adapter struct
+ * @crq:	ibmvmc_crq_msg struct
+ *
+ * This message requests an HMC buffer to be transferred from management
+ * partition ownership to hypervisor ownership. The management partition may
+ * not be able to satisfy the request at a particular point in time if all its
+ * buffers are in use. The management partition requires a depth of at least
+ * one inbound buffer to allow Novalink commands to flow to the hypervisor. It
+ * is, therefore, an interface error for the hypervisor to attempt to remove the
+ * management partition's last buffer.
+ *
+ * The hypervisor is expected to manage buffer usage with the Novalink
+ * application directly and inform the management partition when buffers may be
+ * removed. The typical flow for removing buffers:
+ *
+ * 1. The Novalink application no longer needs a communication path to a
+ *	particular hypervisor function. That function is closed.
+ * 2. The hypervisor and the Novalink application quiesce all traffic to that
+ *	function. The hypervisor requests a reduction in buffer pool size.
+ * 3. The Novalink application acknowledges the reduction in buffer pool size.
+ * 4. The hypervisor sends a Remove Buffer message to the management partition,
+ *	informing it of the reduction in buffers.
+ * 5. The management partition verifies it can remove the buffer. This is
+ *	possible if buffers have been quiesced.
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+/*
+ * The hypervisor requested that we pick an unused buffer, and return it.
+ * Before sending the buffer back, we free any storage associated with the
+ * buffer.
+ */
+static int ibmvmc_rem_buffer(struct crq_server_adapter *adapter,
+			     struct ibmvmc_crq_msg *crq)
+{
+	struct ibmvmc_buffer *buffer;
+	u8 hmc_index;
+	u8 hmc_session;
+	u16 buffer_id = 0;
+	unsigned long flags;
+	int rc = 0;
+
+	if (!crq)
+		return -1;
+
+	hmc_session = crq->hmc_session;
+	hmc_index = crq->hmc_index;
+
+	if (hmc_index > ibmvmc.max_hmc_index) {
+		dev_warn(adapter->dev, "rem_buffer: invalid hmc_index = 0x%x\n",
+			 hmc_index);
+		ibmvmc_send_rem_buffer_resp(adapter, VMC_MSG_INVALID_HMC_INDEX,
+					    hmc_session, hmc_index, buffer_id);
+		return -1;
+	}
+
+	spin_lock_irqsave(&hmcs[hmc_index].lock, flags);
+	buffer = ibmvmc_get_free_hmc_buffer(adapter, hmc_index);
+	if (!buffer) {
+		dev_info(adapter->dev, "rem_buffer: no buffer to remove\n");
+		spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+		ibmvmc_send_rem_buffer_resp(adapter, VMC_MSG_NO_BUFFER,
+					    hmc_session, hmc_index,
+					    VMC_INVALID_BUFFER_ID);
+		return -1;
+	}
+
+	buffer_id = buffer->id;
+
+	if (buffer->valid)
+		free_dma_buffer(to_vio_dev(adapter->dev),
+				ibmvmc.max_mtu,
+				buffer->real_addr_local,
+				buffer->dma_addr_local);
+
+	memset(buffer, 0, sizeof(struct ibmvmc_buffer));
+	spin_unlock_irqrestore(&hmcs[hmc_index].lock, flags);
+
+	dev_dbg(adapter->dev, "rem_buffer: removed buffer 0x%x.\n", buffer_id);
+	ibmvmc_send_rem_buffer_resp(adapter, VMC_MSG_SUCCESS, hmc_session,
+				    hmc_index, buffer_id);
+
+	return rc;
+}
+
+static int ibmvmc_recv_msg(struct crq_server_adapter *adapter,
+			   struct ibmvmc_crq_msg *crq)
+{
+	struct ibmvmc_buffer *buffer;
+	struct ibmvmc_hmc *hmc;
+	unsigned long msg_len;
+	u8 hmc_index;
+	u8 hmc_session;
+	u16 buffer_id;
+	unsigned long flags;
+	int rc = 0;
+
+	if (!crq)
+		return -1;
+
+	/* Hypervisor writes CRQs directly into our memory in big endian */
+	dev_dbg(adapter->dev, "Recv_msg: msg from HV 0x%016llx 0x%016llx\n",
+		be64_to_cpu(*((unsigned long *)crq)),
+		be64_to_cpu(*(((unsigned long *)crq) + 1)));
+
+	hmc_session = crq->hmc_session;
+	hmc_index = crq->hmc_index;
+	buffer_id = be16_to_cpu(crq->var2.buffer_id);
+	msg_len = be32_to_cpu(crq->var3.msg_len);
+
+	if (hmc_index > ibmvmc.max_hmc_index) {
+		dev_err(adapter->dev, "Recv_msg: invalid hmc_index = 0x%x\n",
+			hmc_index);
+		ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INVALID_HMC_INDEX,
+					    hmc_session, hmc_index, buffer_id);
+		return -1;
+	}
+
+	if (buffer_id >= ibmvmc.max_buffer_pool_size) {
+		dev_err(adapter->dev, "Recv_msg: invalid buffer_id = 0x%x\n",
+			buffer_id);
+		ibmvmc_send_add_buffer_resp(adapter, VMC_MSG_INVALID_BUFFER_ID,
+					    hmc_session, hmc_index, buffer_id);
+		return -1;
+	}
+
+	hmc = &hmcs[hmc_index];
+	spin_lock_irqsave(&hmc->lock, flags);
+
+	if (hmc->state == ibmhmc_state_free) {
+		dev_err(adapter->dev, "Recv_msg: invalid hmc state = 0x%x\n",
+			hmc->state);
+		/* HMC connection is not valid (possibly was reset under us). */
+		spin_unlock_irqrestore(&hmc->lock, flags);
+		return -1;
+	}
+
+	buffer = &hmc->buffer[buffer_id];
+
+	if (buffer->valid == 0 || buffer->owner == VMC_BUF_OWNER_ALPHA) {
+		dev_err(adapter->dev, "Recv_msg: not valid, or not HV.  0x%x 0x%x\n",
+			buffer->valid, buffer->owner);
+		spin_unlock_irqrestore(&hmc->lock, flags);
+		return -1;
+	}
+
+	/* RDMA the data into the partition. */
+	rc = h_copy_rdma(msg_len,
+			 adapter->riobn,
+			 buffer->dma_addr_remote,
+			 adapter->liobn,
+			 buffer->dma_addr_local);
+
+	dev_dbg(adapter->dev, "Recv_msg: msg_len = 0x%x, buffer_id = 0x%x, queue_head = 0x%x, hmc_idx = 0x%x\n",
+		(unsigned int)msg_len, (unsigned int)buffer_id,
+		(unsigned int)hmc->queue_head, (unsigned int)hmc_index);
+	buffer->msg_len = msg_len;
+	buffer->free = 0;
+	buffer->owner = VMC_BUF_OWNER_ALPHA;
+
+	if (rc) {
+		dev_err(adapter->dev, "Failure in recv_msg: h_copy_rdma = 0x%x\n",
+			rc);
+		spin_unlock_irqrestore(&hmc->lock, flags);
+		return -1;
+	}
+
+	/* Must be locked because read operates on the same data */
+	hmc->queue_outbound_msgs[hmc->queue_head] = buffer_id;
+	hmc->queue_head++;
+	if (hmc->queue_head == ibmvmc_max_buf_pool_size)
+		hmc->queue_head = 0;
+
+	if (hmc->queue_head == hmc->queue_tail)
+		dev_err(adapter->dev, "outbound buffer queue wrapped.\n");
+
+	spin_unlock_irqrestore(&hmc->lock, flags);
+
+	wake_up_interruptible(&ibmvmc_read_wait);
+
+	return 0;
+}
+
+/**
+ * ibmvmc_process_capabilities - Process Capabilities
+ *
+ * @adapter:	crq_server_adapter struct
+ * @crqp:	ibmvmc_crq_msg struct
+ *
+ */
+static void ibmvmc_process_capabilities(struct crq_server_adapter *adapter,
+					struct ibmvmc_crq_msg *crqp)
+{
+	struct ibmvmc_admin_crq_msg *crq = (struct ibmvmc_admin_crq_msg *)crqp;
+
+	if ((be16_to_cpu(crq->version) >> 8) !=
+			(IBMVMC_PROTOCOL_VERSION >> 8)) {
+		dev_err(adapter->dev, "init failed, incompatible versions 0x%x 0x%x\n",
+			be16_to_cpu(crq->version),
+			IBMVMC_PROTOCOL_VERSION);
+		ibmvmc.state = ibmvmc_state_failed;
+		return;
+	}
+
+	ibmvmc.max_mtu = min_t(u32, ibmvmc_max_mtu, be32_to_cpu(crq->max_mtu));
+	ibmvmc.max_buffer_pool_size = min_t(u16, ibmvmc_max_buf_pool_size,
+					    be16_to_cpu(crq->pool_size));
+	ibmvmc.max_hmc_index = min_t(u8, ibmvmc_max_hmcs, crq->max_hmc) - 1;
+	ibmvmc.state = ibmvmc_state_ready;
+
+	dev_info(adapter->dev, "Capabilities: mtu=0x%x, pool_size=0x%x, max_hmc=0x%x\n",
+		 ibmvmc.max_mtu, ibmvmc.max_buffer_pool_size,
+		 ibmvmc.max_hmc_index);
+}
+
+/**
+ * ibmvmc_validate_hmc_session - Validate HMC Session
+ *
+ * @adapter:	crq_server_adapter struct
+ * @crq:	ibmvmc_crq_msg struct
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static int ibmvmc_validate_hmc_session(struct crq_server_adapter *adapter,
+				       struct ibmvmc_crq_msg *crq)
+{
+	unsigned char hmc_index;
+
+	hmc_index = crq->hmc_index;
+
+	if (crq->hmc_session == 0)
+		return 0;
+
+	if (hmc_index > ibmvmc.max_hmc_index)
+		return -1;
+
+	if (hmcs[hmc_index].session != crq->hmc_session) {
+		dev_warn(adapter->dev, "Drop, bad session: expected 0x%x, recv 0x%x\n",
+			 hmcs[hmc_index].session, crq->hmc_session);
+		return -1;
+	}
+
+	return 0;
+}
+
+/**
+ * ibmvmc_reset - Reset
+ *
+ * @adapter:	crq_server_adapter struct
+ * @xport_event:	export_event field
+ *
+ * Closes all HMC sessions and conditionally schedules a CRQ reset.
+ * @xport_event: If true, the partner closed their CRQ; we don't need to reset.
+ *               If false, we need to schedule a CRQ reset.
+ */
+static void ibmvmc_reset(struct crq_server_adapter *adapter, bool xport_event)
+{
+	int i;
+
+	if (ibmvmc.state != ibmvmc_state_sched_reset) {
+		dev_info(adapter->dev, "*** Reset to initial state.\n");
+		for (i = 0; i < ibmvmc_max_hmcs; i++)
+			ibmvmc_return_hmc(&hmcs[i], xport_event);
+
+		if (xport_event) {
+			/* CRQ was closed by the partner.  We don't need to do
+			 * anything except set ourself to the correct state to
+			 * handle init msgs.
+			 */
+			ibmvmc.state = ibmvmc_state_crqinit;
+		} else {
+			/* The partner did not close their CRQ - instead, we're
+			 * closing the CRQ on our end. Need to schedule this
+			 * for process context, because CRQ reset may require a
+			 * sleep.
+			 *
+			 * Setting ibmvmc.state here immediately prevents
+			 * ibmvmc_open from completing until the reset
+			 * completes in process context.
+			 */
+			ibmvmc.state = ibmvmc_state_sched_reset;
+			dev_dbg(adapter->dev, "Device reset scheduled");
+			wake_up_interruptible(&adapter->reset_wait_queue);
+		}
+	}
+}
+
+/**
+ * ibmvmc_reset_task - Reset Task
+ *
+ * @data:	Data field
+ *
+ * Performs a CRQ reset of the VMC device in process context.
+ * NOTE: This function should not be called directly, use ibmvmc_reset.
+ */
+static int ibmvmc_reset_task(void *data)
+{
+	struct crq_server_adapter *adapter = data;
+	int rc;
+
+	set_user_nice(current, -20);
+
+	while (!kthread_should_stop()) {
+		wait_event_interruptible(adapter->reset_wait_queue,
+			(ibmvmc.state == ibmvmc_state_sched_reset) ||
+			kthread_should_stop());
+
+		if (kthread_should_stop())
+			break;
+
+		dev_dbg(adapter->dev, "CRQ resetting in process context");
+		tasklet_disable(&adapter->work_task);
+
+		rc = ibmvmc_reset_crq_queue(adapter);
+
+		if (rc != H_SUCCESS && rc != H_RESOURCE) {
+			dev_err(adapter->dev, "Error initializing CRQ.  rc = 0x%x\n",
+				rc);
+			ibmvmc.state = ibmvmc_state_failed;
+		} else {
+			ibmvmc.state = ibmvmc_state_crqinit;
+
+			if (ibmvmc_send_crq(adapter, 0xC001000000000000LL, 0)
+			    != 0 && rc != H_RESOURCE)
+				dev_warn(adapter->dev, "Failed to send initialize CRQ message\n");
+		}
+
+		vio_enable_interrupts(to_vio_dev(adapter->dev));
+		tasklet_enable(&adapter->work_task);
+	}
+
+	return 0;
+}
+
+/**
+ * ibmvmc_process_open_resp - Process Open Response
+ *
+ * @crq: ibmvmc_crq_msg struct
+ * @adapter:    crq_server_adapter struct
+ *
+ * This command is sent by the hypervisor in response to the Interface
+ * Open message. When this message is received, the indicated buffer is
+ * again available for management partition use.
+ */
+static void ibmvmc_process_open_resp(struct ibmvmc_crq_msg *crq,
+				     struct crq_server_adapter *adapter)
+{
+	unsigned char hmc_index;
+	unsigned short buffer_id;
+
+	hmc_index = crq->hmc_index;
+	if (hmc_index > ibmvmc.max_hmc_index) {
+		/* Why would PHYP give an index > max negotiated? */
+		ibmvmc_reset(adapter, false);
+		return;
+	}
+
+	if (crq->status) {
+		dev_warn(adapter->dev, "open_resp: failed - status 0x%x\n",
+			 crq->status);
+		ibmvmc_return_hmc(&hmcs[hmc_index], false);
+		return;
+	}
+
+	if (hmcs[hmc_index].state == ibmhmc_state_opening) {
+		buffer_id = be16_to_cpu(crq->var2.buffer_id);
+		if (buffer_id >= ibmvmc.max_buffer_pool_size) {
+			dev_err(adapter->dev, "open_resp: invalid buffer_id = 0x%x\n",
+				buffer_id);
+			hmcs[hmc_index].state = ibmhmc_state_failed;
+		} else {
+			ibmvmc_free_hmc_buffer(&hmcs[hmc_index],
+					       &hmcs[hmc_index].buffer[buffer_id]);
+			hmcs[hmc_index].state = ibmhmc_state_ready;
+			dev_dbg(adapter->dev, "open_resp: set hmc state = ready\n");
+		}
+	} else {
+		dev_warn(adapter->dev, "open_resp: invalid hmc state (0x%x)\n",
+			 hmcs[hmc_index].state);
+	}
+}
+
+/**
+ * ibmvmc_process_close_resp - Process Close Response
+ *
+ * @crq: ibmvmc_crq_msg struct
+ * @adapter:    crq_server_adapter struct
+ *
+ * This command is sent by the hypervisor in response to the Novalink Interface
+ * Close message.
+ *
+ * If the close fails, simply reset the entire driver as the state of the VMC
+ * must be in tough shape.
+ */
+static void ibmvmc_process_close_resp(struct ibmvmc_crq_msg *crq,
+				      struct crq_server_adapter *adapter)
+{
+	unsigned char hmc_index;
+
+	hmc_index = crq->hmc_index;
+	if (hmc_index > ibmvmc.max_hmc_index) {
+		ibmvmc_reset(adapter, false);
+		return;
+	}
+
+	if (crq->status) {
+		dev_warn(adapter->dev, "close_resp: failed - status 0x%x\n",
+			 crq->status);
+		ibmvmc_reset(adapter, false);
+		return;
+	}
+
+	ibmvmc_return_hmc(&hmcs[hmc_index], false);
+}
+
+/**
+ * ibmvmc_crq_process - Process CRQ
+ *
+ * @adapter:    crq_server_adapter struct
+ * @crq:	ibmvmc_crq_msg struct
+ *
+ * Process the CRQ message based upon the type of message received.
+ *
+ */
+static void ibmvmc_crq_process(struct crq_server_adapter *adapter,
+			       struct ibmvmc_crq_msg *crq)
+{
+	switch (crq->type) {
+	case VMC_MSG_CAP_RESP:
+		dev_dbg(adapter->dev, "CRQ recv: capabilities resp (0x%x)\n",
+			crq->type);
+		if (ibmvmc.state == ibmvmc_state_capabilities)
+			ibmvmc_process_capabilities(adapter, crq);
+		else
+			dev_warn(adapter->dev, "caps msg invalid in state 0x%x\n",
+				 ibmvmc.state);
+		break;
+	case VMC_MSG_OPEN_RESP:
+		dev_dbg(adapter->dev, "CRQ recv: open resp (0x%x)\n",
+			crq->type);
+		if (ibmvmc_validate_hmc_session(adapter, crq) == 0)
+			ibmvmc_process_open_resp(crq, adapter);
+		break;
+	case VMC_MSG_ADD_BUF:
+		dev_dbg(adapter->dev, "CRQ recv: add buf (0x%x)\n",
+			crq->type);
+		if (ibmvmc_validate_hmc_session(adapter, crq) == 0)
+			ibmvmc_add_buffer(adapter, crq);
+		break;
+	case VMC_MSG_REM_BUF:
+		dev_dbg(adapter->dev, "CRQ recv: rem buf (0x%x)\n",
+			crq->type);
+		if (ibmvmc_validate_hmc_session(adapter, crq) == 0)
+			ibmvmc_rem_buffer(adapter, crq);
+		break;
+	case VMC_MSG_SIGNAL:
+		dev_dbg(adapter->dev, "CRQ recv: signal msg (0x%x)\n",
+			crq->type);
+		if (ibmvmc_validate_hmc_session(adapter, crq) == 0)
+			ibmvmc_recv_msg(adapter, crq);
+		break;
+	case VMC_MSG_CLOSE_RESP:
+		dev_dbg(adapter->dev, "CRQ recv: close resp (0x%x)\n",
+			crq->type);
+		if (ibmvmc_validate_hmc_session(adapter, crq) == 0)
+			ibmvmc_process_close_resp(crq, adapter);
+		break;
+	case VMC_MSG_CAP:
+	case VMC_MSG_OPEN:
+	case VMC_MSG_CLOSE:
+	case VMC_MSG_ADD_BUF_RESP:
+	case VMC_MSG_REM_BUF_RESP:
+		dev_warn(adapter->dev, "CRQ recv: unexpected msg (0x%x)\n",
+			 crq->type);
+		break;
+	default:
+		dev_warn(adapter->dev, "CRQ recv: unknown msg (0x%x)\n",
+			 crq->type);
+		break;
+	}
+}
+
+/**
+ * ibmvmc_handle_crq_init - Handle CRQ Init
+ *
+ * @crq:	ibmvmc_crq_msg struct
+ * @adapter:	crq_server_adapter struct
+ *
+ * Handle the type of crq initialization based on whether
+ * it is a message or a response.
+ *
+ */
+static void ibmvmc_handle_crq_init(struct ibmvmc_crq_msg *crq,
+				   struct crq_server_adapter *adapter)
+{
+	switch (crq->type) {
+	case 0x01:	/* Initialization message */
+		dev_dbg(adapter->dev, "CRQ recv: CRQ init msg - state 0x%x\n",
+			ibmvmc.state);
+		if (ibmvmc.state == ibmvmc_state_crqinit) {
+			/* Send back a response */
+			if (ibmvmc_send_crq(adapter, 0xC002000000000000,
+					    0) == 0)
+				ibmvmc_send_capabilities(adapter);
+			else
+				dev_err(adapter->dev, " Unable to send init rsp\n");
+		} else {
+			dev_err(adapter->dev, "Invalid state 0x%x mtu = 0x%x\n",
+				ibmvmc.state, ibmvmc.max_mtu);
+		}
+
+		break;
+	case 0x02:	/* Initialization response */
+		dev_dbg(adapter->dev, "CRQ recv: initialization resp msg - state 0x%x\n",
+			ibmvmc.state);
+		if (ibmvmc.state == ibmvmc_state_crqinit)
+			ibmvmc_send_capabilities(adapter);
+		break;
+	default:
+		dev_warn(adapter->dev, "Unknown crq message type 0x%lx\n",
+			 (unsigned long)crq->type);
+	}
+}
+
+/**
+ * ibmvmc_handle_crq - Handle CRQ
+ *
+ * @crq:	ibmvmc_crq_msg struct
+ * @adapter:	crq_server_adapter struct
+ *
+ * Read the command elements from the command queue and execute the
+ * requests based upon the type of crq message.
+ *
+ */
+static void ibmvmc_handle_crq(struct ibmvmc_crq_msg *crq,
+			      struct crq_server_adapter *adapter)
+{
+	switch (crq->valid) {
+	case 0xC0:		/* initialization */
+		ibmvmc_handle_crq_init(crq, adapter);
+		break;
+	case 0xFF:	/* Hypervisor telling us the connection is closed */
+		dev_warn(adapter->dev, "CRQ recv: virtual adapter failed - resetting.\n");
+		ibmvmc_reset(adapter, true);
+		break;
+	case 0x80:	/* real payload */
+		ibmvmc_crq_process(adapter, crq);
+		break;
+	default:
+		dev_warn(adapter->dev, "CRQ recv: unknown msg 0x%02x.\n",
+			 crq->valid);
+		break;
+	}
+}
+
+static void ibmvmc_task(unsigned long data)
+{
+	struct crq_server_adapter *adapter =
+		(struct crq_server_adapter *)data;
+	struct vio_dev *vdev = to_vio_dev(adapter->dev);
+	struct ibmvmc_crq_msg *crq;
+	int done = 0;
+
+	while (!done) {
+		/* Pull all the valid messages off the CRQ */
+		while ((crq = crq_queue_next_crq(&adapter->queue)) != NULL) {
+			ibmvmc_handle_crq(crq, adapter);
+			crq->valid = 0x00;
+			/* CRQ reset was requested, stop processing CRQs.
+			 * Interrupts will be re-enabled by the reset task.
+			 */
+			if (ibmvmc.state == ibmvmc_state_sched_reset)
+				return;
+		}
+
+		vio_enable_interrupts(vdev);
+		crq = crq_queue_next_crq(&adapter->queue);
+		if (crq) {
+			vio_disable_interrupts(vdev);
+			ibmvmc_handle_crq(crq, adapter);
+			crq->valid = 0x00;
+			/* CRQ reset was requested, stop processing CRQs.
+			 * Interrupts will be re-enabled by the reset task.
+			 */
+			if (ibmvmc.state == ibmvmc_state_sched_reset)
+				return;
+		} else {
+			done = 1;
+		}
+	}
+}
+
+/**
+ * ibmvmc_init_crq_queue - Init CRQ Queue
+ *
+ * @adapter:	crq_server_adapter struct
+ *
+ * Return:
+ *	0 - Success
+ *	Non-zero - Failure
+ */
+static int ibmvmc_init_crq_queue(struct crq_server_adapter *adapter)
+{
+	struct vio_dev *vdev = to_vio_dev(adapter->dev);
+	struct crq_queue *queue = &adapter->queue;
+	int rc;
+	int retrc;
+
+	queue->msgs = (struct ibmvmc_crq_msg *)get_zeroed_page(GFP_KERNEL);
+
+	if (!queue->msgs)
+		goto malloc_failed;
+
+	queue->size = PAGE_SIZE / sizeof(*queue->msgs);
+
+	queue->msg_token = dma_map_single(adapter->dev, queue->msgs,
+					  queue->size * sizeof(*queue->msgs),
+					  DMA_BIDIRECTIONAL);
+
+	if (dma_mapping_error(adapter->dev, queue->msg_token))
+		goto map_failed;
+
+	retrc = plpar_hcall_norets(H_REG_CRQ,
+				   vdev->unit_address,
+				   queue->msg_token, PAGE_SIZE);
+	retrc = rc;
+
+	if (rc == H_RESOURCE)
+		rc = ibmvmc_reset_crq_queue(adapter);
+
+	if (rc == 2) {
+		dev_warn(adapter->dev, "Partner adapter not ready\n");
+		retrc = 0;
+	} else if (rc != 0) {
+		dev_err(adapter->dev, "Error %d opening adapter\n", rc);
+		goto reg_crq_failed;
+	}
+
+	queue->cur = 0;
+	spin_lock_init(&queue->lock);
+
+	tasklet_init(&adapter->work_task, ibmvmc_task, (unsigned long)adapter);
+
+	if (request_irq(vdev->irq,
+			ibmvmc_handle_event,
+			0, "ibmvmc", (void *)adapter) != 0) {
+		dev_err(adapter->dev, "couldn't register irq 0x%x\n",
+			vdev->irq);
+		goto req_irq_failed;
+	}
+
+	rc = vio_enable_interrupts(vdev);
+	if (rc != 0) {
+		dev_err(adapter->dev, "Error %d enabling interrupts!!!\n", rc);
+		goto req_irq_failed;
+	}
+
+	return retrc;
+
+req_irq_failed:
+	/* Cannot have any work since we either never got our IRQ registered,
+	 * or never got interrupts enabled
+	 */
+	tasklet_kill(&adapter->work_task);
+	h_free_crq(vdev->unit_address);
+reg_crq_failed:
+	dma_unmap_single(adapter->dev,
+			 queue->msg_token,
+			 queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);
+map_failed:
+	free_page((unsigned long)queue->msgs);
+malloc_failed:
+	return -ENOMEM;
+}
+
+/* Fill in the liobn and riobn fields on the adapter */
+static int read_dma_window(struct vio_dev *vdev,
+			   struct crq_server_adapter *adapter)
+{
+	const __be32 *dma_window;
+	const __be32 *prop;
+
+	/* TODO Using of_parse_dma_window would be better, but it doesn't give
+	 * a way to read multiple windows without already knowing the size of
+	 * a window or the number of windows
+	 */
+	dma_window =
+		(const __be32 *)vio_get_attribute(vdev, "ibm,my-dma-window",
+						NULL);
+	if (!dma_window) {
+		dev_warn(adapter->dev, "Couldn't find ibm,my-dma-window property\n");
+		return -1;
+	}
+
+	adapter->liobn = be32_to_cpu(*dma_window);
+	dma_window++;
+
+	prop = (const __be32 *)vio_get_attribute(vdev, "ibm,#dma-address-cells",
+						NULL);
+	if (!prop) {
+		dev_warn(adapter->dev, "Couldn't find ibm,#dma-address-cells property\n");
+		dma_window++;
+	} else {
+		dma_window += be32_to_cpu(*prop);
+	}
+
+	prop = (const __be32 *)vio_get_attribute(vdev, "ibm,#dma-size-cells",
+						NULL);
+	if (!prop) {
+		dev_warn(adapter->dev, "Couldn't find ibm,#dma-size-cells property\n");
+		dma_window++;
+	} else {
+		dma_window += be32_to_cpu(*prop);
+	}
+
+	/* dma_window should point to the second window now */
+	adapter->riobn = be32_to_cpu(*dma_window);
+
+	return 0;
+}
+
+static int ibmvmc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
+{
+	struct crq_server_adapter *adapter = &ibmvmc_adapter;
+	int rc;
+
+	dev_set_drvdata(&vdev->dev, NULL);
+	memset(adapter, 0, sizeof(*adapter));
+	adapter->dev = &vdev->dev;
+
+	dev_info(adapter->dev, "Probe for UA 0x%x\n", vdev->unit_address);
+
+	rc = read_dma_window(vdev, adapter);
+	if (rc != 0) {
+		ibmvmc.state = ibmvmc_state_failed;
+		return -1;
+	}
+
+	dev_dbg(adapter->dev, "Probe: liobn 0x%x, riobn 0x%x\n",
+		adapter->liobn, adapter->riobn);
+
+	init_waitqueue_head(&adapter->reset_wait_queue);
+	adapter->reset_task = kthread_run(ibmvmc_reset_task, adapter, "ibmvmc");
+	if (IS_ERR(adapter->reset_task)) {
+		dev_err(adapter->dev, "Failed to start reset thread\n");
+		ibmvmc.state = ibmvmc_state_failed;
+		rc = PTR_ERR(adapter->reset_task);
+		adapter->reset_task = NULL;
+		return rc;
+	}
+
+	rc = ibmvmc_init_crq_queue(adapter);
+	if (rc != 0 && rc != H_RESOURCE) {
+		dev_err(adapter->dev, "Error initializing CRQ.  rc = 0x%x\n",
+			rc);
+		ibmvmc.state = ibmvmc_state_failed;
+		goto crq_failed;
+	}
+
+	ibmvmc.state = ibmvmc_state_crqinit;
+
+	/* Try to send an initialization message.  Note that this is allowed
+	 * to fail if the other end is not acive.  In that case we just wait
+	 * for the other side to initialize.
+	 */
+	if (ibmvmc_send_crq(adapter, 0xC001000000000000LL, 0) != 0 &&
+	    rc != H_RESOURCE)
+		dev_warn(adapter->dev, "Failed to send initialize CRQ message\n");
+
+	dev_set_drvdata(&vdev->dev, adapter);
+
+	return 0;
+
+crq_failed:
+	kthread_stop(adapter->reset_task);
+	adapter->reset_task = NULL;
+	return -EPERM;
+}
+
+static int ibmvmc_remove(struct vio_dev *vdev)
+{
+	struct crq_server_adapter *adapter = dev_get_drvdata(&vdev->dev);
+
+	dev_info(adapter->dev, "Entering remove for UA 0x%x\n",
+		 vdev->unit_address);
+	ibmvmc_release_crq_queue(adapter);
+
+	return 0;
+}
+
+static struct vio_device_id ibmvmc_device_table[] = {
+	{ "ibm,vmc", "IBM,vmc" },
+	{ "", "" }
+};
+MODULE_DEVICE_TABLE(vio, ibmvmc_device_table);
+
+static struct vio_driver ibmvmc_driver = {
+	.name        = ibmvmc_driver_name,
+	.id_table    = ibmvmc_device_table,
+	.probe       = ibmvmc_probe,
+	.remove      = ibmvmc_remove,
+};
+
+static void __init ibmvmc_scrub_module_parms(void)
+{
+	if (ibmvmc_max_mtu > MAX_MTU) {
+		pr_warn("ibmvmc: Max MTU reduced to %d\n", MAX_MTU);
+		ibmvmc_max_mtu = MAX_MTU;
+	} else if (ibmvmc_max_mtu < MIN_MTU) {
+		pr_warn("ibmvmc: Max MTU increased to %d\n", MIN_MTU);
+		ibmvmc_max_mtu = MIN_MTU;
+	}
+
+	if (ibmvmc_max_buf_pool_size > MAX_BUF_POOL_SIZE) {
+		pr_warn("ibmvmc: Max buffer pool size reduced to %d\n",
+			MAX_BUF_POOL_SIZE);
+		ibmvmc_max_buf_pool_size = MAX_BUF_POOL_SIZE;
+	} else if (ibmvmc_max_buf_pool_size < MIN_BUF_POOL_SIZE) {
+		pr_warn("ibmvmc: Max buffer pool size increased to %d\n",
+			MIN_BUF_POOL_SIZE);
+		ibmvmc_max_buf_pool_size = MIN_BUF_POOL_SIZE;
+	}
+
+	if (ibmvmc_max_hmcs > MAX_HMCS) {
+		pr_warn("ibmvmc: Max HMCs reduced to %d\n", MAX_HMCS);
+		ibmvmc_max_hmcs = MAX_HMCS;
+	} else if (ibmvmc_max_hmcs < MIN_HMCS) {
+		pr_warn("ibmvmc: Max HMCs increased to %d\n", MIN_HMCS);
+		ibmvmc_max_hmcs = MIN_HMCS;
+	}
+}
+
+static struct miscdevice ibmvmc_miscdev = {
+	.name = ibmvmc_driver_name,
+	.minor = MISC_DYNAMIC_MINOR,
+	.fops = &ibmvmc_fops,
+};
+
+static int __init ibmvmc_module_init(void)
+{
+	int rc, i, j;
+
+	ibmvmc.state = ibmvmc_state_initial;
+	pr_info("ibmvmc: version %s\n", IBMVMC_DRIVER_VERSION);
+
+	rc = misc_register(&ibmvmc_miscdev);
+	if (rc) {
+		pr_err("ibmvmc: misc registration failed\n");
+		goto misc_register_failed;
+	}
+	pr_info("ibmvmc: node %d:%d\n", MISC_MAJOR,
+		ibmvmc_miscdev.minor);
+
+	/* Initialize data structures */
+	memset(hmcs, 0, sizeof(struct ibmvmc_hmc) * MAX_HMCS);
+	for (i = 0; i < MAX_HMCS; i++) {
+		spin_lock_init(&hmcs[i].lock);
+		hmcs[i].state = ibmhmc_state_free;
+		for (j = 0; j < MAX_BUF_POOL_SIZE; j++)
+			hmcs[i].queue_outbound_msgs[j] = VMC_INVALID_BUFFER_ID;
+	}
+
+	/* Sanity check module parms */
+	ibmvmc_scrub_module_parms();
+
+	/*
+	 * Initialize some reasonable values.  Might be negotiated smaller
+	 * values during the capabilities exchange.
+	 */
+	ibmvmc.max_mtu = ibmvmc_max_mtu;
+	ibmvmc.max_buffer_pool_size = ibmvmc_max_buf_pool_size;
+	ibmvmc.max_hmc_index = ibmvmc_max_hmcs - 1;
+
+	rc = vio_register_driver(&ibmvmc_driver);
+
+	if (rc) {
+		pr_err("ibmvmc: rc %d from vio_register_driver\n", rc);
+		goto vio_reg_failed;
+	}
+
+	return 0;
+
+vio_reg_failed:
+	misc_deregister(&ibmvmc_miscdev);
+misc_register_failed:
+	return rc;
+}
+
+static void __exit ibmvmc_module_exit(void)
+{
+	pr_info("ibmvmc: module exit\n");
+	vio_unregister_driver(&ibmvmc_driver);
+	misc_deregister(&ibmvmc_miscdev);
+}
+
+module_init(ibmvmc_module_init);
+module_exit(ibmvmc_module_exit);
+
+module_param_named(buf_pool_size, ibmvmc_max_buf_pool_size,
+		   int, 0644);
+MODULE_PARM_DESC(buf_pool_size, "Buffer pool size");
+module_param_named(max_hmcs, ibmvmc_max_hmcs, int, 0644);
+MODULE_PARM_DESC(max_hmcs, "Max HMCs");
+module_param_named(max_mtu, ibmvmc_max_mtu, int, 0644);
+MODULE_PARM_DESC(max_mtu, "Max MTU");
+
+MODULE_AUTHOR("Steven Royer <seroyer@linux.vnet.ibm.com>");
+MODULE_DESCRIPTION("IBM VMC");
+MODULE_VERSION(IBMVMC_DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/misc/ibmvmc.h b/drivers/misc/ibmvmc.h
new file mode 100644
index 0000000..e140ada
--- /dev/null
+++ b/drivers/misc/ibmvmc.h
@@ -0,0 +1,209 @@
+/* SPDX-License-Identifier: GPL-2.0+
+ *
+ * linux/drivers/misc/ibmvmc.h
+ *
+ * IBM Power Systems Virtual Management Channel Support.
+ *
+ * Copyright (c) 2004, 2018 IBM Corp.
+ *   Dave Engebretsen engebret@us.ibm.com
+ *   Steven Royer seroyer@linux.vnet.ibm.com
+ *   Adam Reznechek adreznec@linux.vnet.ibm.com
+ *   Bryant G. Ly <bryantly@linux.vnet.ibm.com>
+ */
+#ifndef IBMVMC_H
+#define IBMVMC_H
+
+#include <linux/types.h>
+#include <linux/cdev.h>
+
+#include <asm/vio.h>
+
+#define IBMVMC_PROTOCOL_VERSION    0x0101
+
+#define MIN_BUF_POOL_SIZE 16
+#define MIN_HMCS          1
+#define MIN_MTU           4096
+#define MAX_BUF_POOL_SIZE 64
+#define MAX_HMCS          2
+#define MAX_MTU           (4 * 4096)
+#define DEFAULT_BUF_POOL_SIZE 32
+#define DEFAULT_HMCS          1
+#define DEFAULT_MTU           4096
+#define HMC_ID_LEN        32
+
+#define VMC_INVALID_BUFFER_ID 0xFFFF
+
+/* ioctl numbers */
+#define VMC_BASE	     0xCC
+#define VMC_IOCTL_SETHMCID   _IOW(VMC_BASE, 0x00, unsigned char *)
+#define VMC_IOCTL_QUERY      _IOR(VMC_BASE, 0x01, struct ibmvmc_query_struct)
+#define VMC_IOCTL_REQUESTVMC _IOR(VMC_BASE, 0x02, u32)
+
+#define VMC_MSG_CAP          0x01
+#define VMC_MSG_CAP_RESP     0x81
+#define VMC_MSG_OPEN         0x02
+#define VMC_MSG_OPEN_RESP    0x82
+#define VMC_MSG_CLOSE        0x03
+#define VMC_MSG_CLOSE_RESP   0x83
+#define VMC_MSG_ADD_BUF      0x04
+#define VMC_MSG_ADD_BUF_RESP 0x84
+#define VMC_MSG_REM_BUF      0x05
+#define VMC_MSG_REM_BUF_RESP 0x85
+#define VMC_MSG_SIGNAL       0x06
+
+#define VMC_MSG_SUCCESS 0
+#define VMC_MSG_INVALID_HMC_INDEX 1
+#define VMC_MSG_INVALID_BUFFER_ID 2
+#define VMC_MSG_CLOSED_HMC        3
+#define VMC_MSG_INTERFACE_FAILURE 4
+#define VMC_MSG_NO_BUFFER         5
+
+#define VMC_BUF_OWNER_ALPHA 0
+#define VMC_BUF_OWNER_HV    1
+
+enum ibmvmc_states {
+	ibmvmc_state_sched_reset  = -1,
+	ibmvmc_state_initial      = 0,
+	ibmvmc_state_crqinit      = 1,
+	ibmvmc_state_capabilities = 2,
+	ibmvmc_state_ready        = 3,
+	ibmvmc_state_failed       = 4,
+};
+
+enum ibmhmc_states {
+	/* HMC connection not established */
+	ibmhmc_state_free    = 0,
+
+	/* HMC connection established (open called) */
+	ibmhmc_state_initial = 1,
+
+	/* open msg sent to HV, due to ioctl(1) call */
+	ibmhmc_state_opening = 2,
+
+	/* HMC connection ready, open resp msg from HV */
+	ibmhmc_state_ready   = 3,
+
+	/* HMC connection failure */
+	ibmhmc_state_failed  = 4,
+};
+
+struct ibmvmc_buffer {
+	u8 valid;	/* 1 when DMA storage allocated to buffer          */
+	u8 free;	/* 1 when buffer available for the Alpha Partition */
+	u8 owner;
+	u16 id;
+	u32 size;
+	u32 msg_len;
+	dma_addr_t dma_addr_local;
+	dma_addr_t dma_addr_remote;
+	void *real_addr_local;
+};
+
+struct ibmvmc_admin_crq_msg {
+	u8 valid;	/* RPA Defined           */
+	u8 type;	/* ibmvmc msg type       */
+	u8 status;	/* Response msg status. Zero is success and on failure,
+			 * either 1 - General Failure, or 2 - Invalid Version is
+			 * returned.
+			 */
+	u8 rsvd[2];
+	u8 max_hmc;	/* Max # of independent HMC connections supported */
+	__be16 pool_size;	/* Maximum number of buffers supported per HMC
+				 * connection
+				 */
+	__be32 max_mtu;		/* Maximum message size supported (bytes) */
+	__be16 crq_size;	/* # of entries available in the CRQ for the
+				 * source partition. The target partition must
+				 * limit the number of outstanding messages to
+				 * one half or less.
+				 */
+	__be16 version;	/* Indicates the code level of the management partition
+			 * or the hypervisor with the high-order byte
+			 * indicating a major version and the low-order byte
+			 * indicating a minor version.
+			 */
+};
+
+struct ibmvmc_crq_msg {
+	u8 valid;     /* RPA Defined           */
+	u8 type;      /* ibmvmc msg type       */
+	u8 status;    /* Response msg status   */
+	union {
+		u8 rsvd;  /* Reserved              */
+		u8 owner;
+	} var1;
+	u8 hmc_session;	/* Session Identifier for the current VMC connection */
+	u8 hmc_index;	/* A unique HMC Idx would be used if multiple management
+			 * applications running concurrently were desired
+			 */
+	union {
+		__be16 rsvd;
+		__be16 buffer_id;
+	} var2;
+	__be32 rsvd;
+	union {
+		__be32 rsvd;
+		__be32 lioba;
+		__be32 msg_len;
+	} var3;
+};
+
+/* an RPA command/response transport queue */
+struct crq_queue {
+	struct ibmvmc_crq_msg *msgs;
+	int size, cur;
+	dma_addr_t msg_token;
+	spinlock_t lock;
+};
+
+/* VMC server adapter settings */
+struct crq_server_adapter {
+	struct device *dev;
+	struct crq_queue queue;
+	u32 liobn;
+	u32 riobn;
+	struct tasklet_struct work_task;
+	wait_queue_head_t reset_wait_queue;
+	struct task_struct *reset_task;
+};
+
+/* Driver wide settings */
+struct ibmvmc_struct {
+	u32 state;
+	u32 max_mtu;
+	u32 max_buffer_pool_size;
+	u32 max_hmc_index;
+	struct crq_server_adapter *adapter;
+	struct cdev cdev;
+	u32 vmc_drc_index;
+};
+
+struct ibmvmc_file_session;
+
+/* Connection specific settings */
+struct ibmvmc_hmc {
+	u8 session;
+	u8 index;
+	u32 state;
+	struct crq_server_adapter *adapter;
+	spinlock_t lock;
+	unsigned char hmc_id[HMC_ID_LEN];
+	struct ibmvmc_buffer buffer[MAX_BUF_POOL_SIZE];
+	unsigned short queue_outbound_msgs[MAX_BUF_POOL_SIZE];
+	int queue_head, queue_tail;
+	struct ibmvmc_file_session *file_session;
+};
+
+struct ibmvmc_file_session {
+	struct file *file;
+	struct ibmvmc_hmc *hmc;
+	bool valid;
+};
+
+struct ibmvmc_query_struct {
+	int have_vmc;
+	int state;
+	int vmc_drc_index;
+};
+
+#endif /* __IBMVMC_H */
-- 
2.7.2

Re: [PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Randy Dunlap]

On 04/23/18 07:46, Bryant G. Ly wrote:
> This driver is a logical device which provides an
> interface between the hypervisor and a management
> partition.
> 
> This driver is to be used for the POWER Virtual
> Management Channel Virtual Adapter on the PowerVM
> platform. It provides both request/response and
> async message support through the /dev/ibmvmc node.
> 
> Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
> Reviewed-by: Steven Royer <seroyer@linux.vnet.ibm.com>
> Reviewed-by: Adam Reznechek <adreznec@linux.vnet.ibm.com>
> Tested-by: Taylor Jakobson <tjakobs@us.ibm.com>
> Tested-by: Brad Warrum <bwarrum@us.ibm.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> ---
>  Documentation/ioctl/ioctl-number.txt  |    1 +
>  Documentation/misc-devices/ibmvmc.txt |  161 +++
>  MAINTAINERS                           |    6 +
>  arch/powerpc/include/asm/hvcall.h     |    1 +
>  drivers/misc/Kconfig                  |   14 +
>  drivers/misc/Makefile                 |    1 +
>  drivers/misc/ibmvmc.c                 | 2415 +++++++++++++++++++++++++++++++++
>  drivers/misc/ibmvmc.h                 |  209 +++
>  8 files changed, 2808 insertions(+)
>  create mode 100644 Documentation/misc-devices/ibmvmc.txt
>  create mode 100644 drivers/misc/ibmvmc.c
>  create mode 100644 drivers/misc/ibmvmc.h

> diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-devices/ibmvmc.txt
> new file mode 100644
> index 0000000..bae1064
> --- /dev/null
> +++ b/Documentation/misc-devices/ibmvmc.txt
> @@ -0,0 +1,161 @@
> +Kernel Driver ibmvmc
> +====================
> +
> +Authors:
> +	Dave Engebretsen <engebret@us.ibm.com>
> +	Adam Reznechek <adreznec@linux.vnet.ibm.com>
> +	Steven Royer <seroyer@linux.vnet.ibm.com>
> +	Bryant G. Ly <bryantly@linux.vnet.ibm.com>
> +
> +Description
> +===========
> +

...

> +
> +Virtual Management Channel (VMC)
> +A logical device, called the virtual management channel (VMC), is defined
> +for communicating between the Novalink application and the hypervisor.
> +This device, similar to a VSCSI server device, is presented to a designated
> +management partition as a virtual device and is only presented when the
> +system is not HMC managed.
> +This communication device borrows aspects from both VSCSI and ILLAN devices
> +and is implemented using the CRQ and the RDMA interfaces. A three-way
> +handshake is defined that must take place to establish that both the
> +hypervisor and management partition sides of the channel are running prior
> +to sending/receiving any of the protocol messages.
> +This driver also utilizes Transport Event CRQs. CRQ messages that are sent

                                                 Drop           "that" ?
otherwise the sentence construction is ... odd.

> +when the hypervisor detects one of the peer partitions has abnormally
> +terminated, or one side has called H_FREE_CRQ to close their CRQ.
> +Two new classes of CRQ messages are introduced for the VMC device. VMC
> +Administrative messages are used for each partition using the VMC to
> +communicate capabilities to their partner. HMC Interface messages are used
> +for the actual flow of HMC messages between the management partition and
> +the hypervisor. As most HMC messages far exceed the size of a CRQ bugger,

what is a bugger?
[reads more]
oh, buffer?

> +a virtual DMA (RMDA) of the HMC message data is done prior to each HMC
> +Interface CRQ message. Only the management partition drives RDMA
> +operations; hypervisors never directly causes the movement of message data.
> +
> +Example Management Partition VMC Driver Interface
> +=================================================

...


Looks pretty good.  In general (IMO), it could use more white space (like blank
lines after section names.)

If you fix those small items (buggers) above, you can add:
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>

thanks,
-- 
~Randy
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Re: [PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Randy Dunlap]

On 04/23/18 07:46, Bryant G. Ly wrote:
> This driver is a logical device which provides an
> interface between the hypervisor and a management
> partition.
> 
> This driver is to be used for the POWER Virtual
> Management Channel Virtual Adapter on the PowerVM
> platform. It provides both request/response and
> async message support through the /dev/ibmvmc node.
> 
> Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
> Reviewed-by: Steven Royer <seroyer@linux.vnet.ibm.com>
> Reviewed-by: Adam Reznechek <adreznec@linux.vnet.ibm.com>
> Tested-by: Taylor Jakobson <tjakobs@us.ibm.com>
> Tested-by: Brad Warrum <bwarrum@us.ibm.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> ---
>  Documentation/ioctl/ioctl-number.txt  |    1 +
>  Documentation/misc-devices/ibmvmc.txt |  161 +++
>  MAINTAINERS                           |    6 +
>  arch/powerpc/include/asm/hvcall.h     |    1 +
>  drivers/misc/Kconfig                  |   14 +
>  drivers/misc/Makefile                 |    1 +
>  drivers/misc/ibmvmc.c                 | 2415 +++++++++++++++++++++++++++++++++
>  drivers/misc/ibmvmc.h                 |  209 +++
>  8 files changed, 2808 insertions(+)
>  create mode 100644 Documentation/misc-devices/ibmvmc.txt
>  create mode 100644 drivers/misc/ibmvmc.c
>  create mode 100644 drivers/misc/ibmvmc.h

> diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-devices/ibmvmc.txt
> new file mode 100644
> index 0000000..bae1064
> --- /dev/null
> +++ b/Documentation/misc-devices/ibmvmc.txt
> @@ -0,0 +1,161 @@
> +Kernel Driver ibmvmc
> +====================
> +
> +Authors:
> +	Dave Engebretsen <engebret@us.ibm.com>
> +	Adam Reznechek <adreznec@linux.vnet.ibm.com>
> +	Steven Royer <seroyer@linux.vnet.ibm.com>
> +	Bryant G. Ly <bryantly@linux.vnet.ibm.com>
> +
> +Description
> +===========
> +

...

> +
> +Virtual Management Channel (VMC)
> +A logical device, called the virtual management channel (VMC), is defined
> +for communicating between the Novalink application and the hypervisor.
> +This device, similar to a VSCSI server device, is presented to a designated
> +management partition as a virtual device and is only presented when the
> +system is not HMC managed.
> +This communication device borrows aspects from both VSCSI and ILLAN devices
> +and is implemented using the CRQ and the RDMA interfaces. A three-way
> +handshake is defined that must take place to establish that both the
> +hypervisor and management partition sides of the channel are running prior
> +to sending/receiving any of the protocol messages.
> +This driver also utilizes Transport Event CRQs. CRQ messages that are sent

                                                 Drop           "that" ?
otherwise the sentence construction is ... odd.

> +when the hypervisor detects one of the peer partitions has abnormally
> +terminated, or one side has called H_FREE_CRQ to close their CRQ.
> +Two new classes of CRQ messages are introduced for the VMC device. VMC
> +Administrative messages are used for each partition using the VMC to
> +communicate capabilities to their partner. HMC Interface messages are used
> +for the actual flow of HMC messages between the management partition and
> +the hypervisor. As most HMC messages far exceed the size of a CRQ bugger,

what is a bugger?
[reads more]
oh, buffer?

> +a virtual DMA (RMDA) of the HMC message data is done prior to each HMC
> +Interface CRQ message. Only the management partition drives RDMA
> +operations; hypervisors never directly causes the movement of message data.
> +
> +Example Management Partition VMC Driver Interface
> +=================================================

...


Looks pretty good.  In general (IMO), it could use more white space (like blank
lines after section names.)

If you fix those small items (buggers) above, you can add:
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>

thanks,
-- 
~Randy

Re: [PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Greg KH]

On Mon, Apr 23, 2018 at 11:38:18AM -0700, Randy Dunlap wrote:
> On 04/23/18 07:46, Bryant G. Ly wrote:
> > This driver is a logical device which provides an
> > interface between the hypervisor and a management
> > partition.
> > 
> > This driver is to be used for the POWER Virtual
> > Management Channel Virtual Adapter on the PowerVM
> > platform. It provides both request/response and
> > async message support through the /dev/ibmvmc node.
> > 
> > Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
> > Reviewed-by: Steven Royer <seroyer@linux.vnet.ibm.com>
> > Reviewed-by: Adam Reznechek <adreznec@linux.vnet.ibm.com>
> > Tested-by: Taylor Jakobson <tjakobs@us.ibm.com>
> > Tested-by: Brad Warrum <bwarrum@us.ibm.com>
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Cc: Arnd Bergmann <arnd@arndb.de>
> > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> > Cc: Michael Ellerman <mpe@ellerman.id.au>
> > ---
> >  Documentation/ioctl/ioctl-number.txt  |    1 +
> >  Documentation/misc-devices/ibmvmc.txt |  161 +++
> >  MAINTAINERS                           |    6 +
> >  arch/powerpc/include/asm/hvcall.h     |    1 +
> >  drivers/misc/Kconfig                  |   14 +
> >  drivers/misc/Makefile                 |    1 +
> >  drivers/misc/ibmvmc.c                 | 2415 +++++++++++++++++++++++++++++++++
> >  drivers/misc/ibmvmc.h                 |  209 +++
> >  8 files changed, 2808 insertions(+)
> >  create mode 100644 Documentation/misc-devices/ibmvmc.txt
> >  create mode 100644 drivers/misc/ibmvmc.c
> >  create mode 100644 drivers/misc/ibmvmc.h
> 
> > diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-devices/ibmvmc.txt
> > new file mode 100644
> > index 0000000..bae1064
> > --- /dev/null
> > +++ b/Documentation/misc-devices/ibmvmc.txt

Aren't we doing new documentation in .rst format instead of .txt?

thanks,

greg k-h
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Re: [PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Greg KH]

On Mon, Apr 23, 2018 at 11:38:18AM -0700, Randy Dunlap wrote:
> On 04/23/18 07:46, Bryant G. Ly wrote:
> > This driver is a logical device which provides an
> > interface between the hypervisor and a management
> > partition.
> > 
> > This driver is to be used for the POWER Virtual
> > Management Channel Virtual Adapter on the PowerVM
> > platform. It provides both request/response and
> > async message support through the /dev/ibmvmc node.
> > 
> > Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
> > Reviewed-by: Steven Royer <seroyer@linux.vnet.ibm.com>
> > Reviewed-by: Adam Reznechek <adreznec@linux.vnet.ibm.com>
> > Tested-by: Taylor Jakobson <tjakobs@us.ibm.com>
> > Tested-by: Brad Warrum <bwarrum@us.ibm.com>
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Cc: Arnd Bergmann <arnd@arndb.de>
> > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> > Cc: Michael Ellerman <mpe@ellerman.id.au>
> > ---
> >  Documentation/ioctl/ioctl-number.txt  |    1 +
> >  Documentation/misc-devices/ibmvmc.txt |  161 +++
> >  MAINTAINERS                           |    6 +
> >  arch/powerpc/include/asm/hvcall.h     |    1 +
> >  drivers/misc/Kconfig                  |   14 +
> >  drivers/misc/Makefile                 |    1 +
> >  drivers/misc/ibmvmc.c                 | 2415 +++++++++++++++++++++++++++++++++
> >  drivers/misc/ibmvmc.h                 |  209 +++
> >  8 files changed, 2808 insertions(+)
> >  create mode 100644 Documentation/misc-devices/ibmvmc.txt
> >  create mode 100644 drivers/misc/ibmvmc.c
> >  create mode 100644 drivers/misc/ibmvmc.h
> 
> > diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-devices/ibmvmc.txt
> > new file mode 100644
> > index 0000000..bae1064
> > --- /dev/null
> > +++ b/Documentation/misc-devices/ibmvmc.txt

Aren't we doing new documentation in .rst format instead of .txt?

thanks,

greg k-h

Re: [PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Bryant G. Ly]

On 4/23/18 2:53 PM, Greg KH wrote:

> On Mon, Apr 23, 2018 at 11:38:18AM -0700, Randy Dunlap wrote:
>> On 04/23/18 07:46, Bryant G. Ly wrote:
>>> This driver is a logical device which provides an
>>> interface between the hypervisor and a management
>>> partition.
>>>
>>> This driver is to be used for the POWER Virtual
>>> Management Channel Virtual Adapter on the PowerVM
>>> platform. It provides both request/response and
>>> async message support through the /dev/ibmvmc node.
>>>
>>> Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
>>> Reviewed-by: Steven Royer <seroyer@linux.vnet.ibm.com>
>>> Reviewed-by: Adam Reznechek <adreznec@linux.vnet.ibm.com>
>>> Tested-by: Taylor Jakobson <tjakobs@us.ibm.com>
>>> Tested-by: Brad Warrum <bwarrum@us.ibm.com>
>>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>> Cc: Arnd Bergmann <arnd@arndb.de>
>>> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>>> Cc: Michael Ellerman <mpe@ellerman.id.au>
>>> ---
>>>  Documentation/ioctl/ioctl-number.txt  |    1 +
>>>  Documentation/misc-devices/ibmvmc.txt |  161 +++
>>>  MAINTAINERS                           |    6 +
>>>  arch/powerpc/include/asm/hvcall.h     |    1 +
>>>  drivers/misc/Kconfig                  |   14 +
>>>  drivers/misc/Makefile                 |    1 +
>>>  drivers/misc/ibmvmc.c                 | 2415 +++++++++++++++++++++++++++++++++
>>>  drivers/misc/ibmvmc.h                 |  209 +++
>>>  8 files changed, 2808 insertions(+)
>>>  create mode 100644 Documentation/misc-devices/ibmvmc.txt
>>>  create mode 100644 drivers/misc/ibmvmc.c
>>>  create mode 100644 drivers/misc/ibmvmc.h
>>> diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-devices/ibmvmc.txt
>>> new file mode 100644
>>> index 0000000..bae1064
>>> --- /dev/null
>>> +++ b/Documentation/misc-devices/ibmvmc.txt
> Aren't we doing new documentation in .rst format instead of .txt?
>
> thanks,
>
> greg k-h
>
I will convert to .rst and fix the comments from Randy in the next version.

Thanks, 

Bryant

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Re: [PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Bryant G. Ly]

On 4/23/18 2:53 PM, Greg KH wrote:

> On Mon, Apr 23, 2018 at 11:38:18AM -0700, Randy Dunlap wrote:
>> On 04/23/18 07:46, Bryant G. Ly wrote:
>>> This driver is a logical device which provides an
>>> interface between the hypervisor and a management
>>> partition.
>>>
>>> This driver is to be used for the POWER Virtual
>>> Management Channel Virtual Adapter on the PowerVM
>>> platform. It provides both request/response and
>>> async message support through the /dev/ibmvmc node.
>>>
>>> Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
>>> Reviewed-by: Steven Royer <seroyer@linux.vnet.ibm.com>
>>> Reviewed-by: Adam Reznechek <adreznec@linux.vnet.ibm.com>
>>> Tested-by: Taylor Jakobson <tjakobs@us.ibm.com>
>>> Tested-by: Brad Warrum <bwarrum@us.ibm.com>
>>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>> Cc: Arnd Bergmann <arnd@arndb.de>
>>> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>>> Cc: Michael Ellerman <mpe@ellerman.id.au>
>>> ---
>>>  Documentation/ioctl/ioctl-number.txt  |    1 +
>>>  Documentation/misc-devices/ibmvmc.txt |  161 +++
>>>  MAINTAINERS                           |    6 +
>>>  arch/powerpc/include/asm/hvcall.h     |    1 +
>>>  drivers/misc/Kconfig                  |   14 +
>>>  drivers/misc/Makefile                 |    1 +
>>>  drivers/misc/ibmvmc.c                 | 2415 +++++++++++++++++++++++++++++++++
>>>  drivers/misc/ibmvmc.h                 |  209 +++
>>>  8 files changed, 2808 insertions(+)
>>>  create mode 100644 Documentation/misc-devices/ibmvmc.txt
>>>  create mode 100644 drivers/misc/ibmvmc.c
>>>  create mode 100644 drivers/misc/ibmvmc.h
>>> diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-devices/ibmvmc.txt
>>> new file mode 100644
>>> index 0000000..bae1064
>>> --- /dev/null
>>> +++ b/Documentation/misc-devices/ibmvmc.txt
> Aren't we doing new documentation in .rst format instead of .txt?
>
> thanks,
>
> greg k-h
>
I will convert to .rst and fix the comments from Randy in the next version.

Thanks, 

Bryant

Re: [PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Randy Dunlap]

On 04/23/18 12:53, Greg KH wrote:
> On Mon, Apr 23, 2018 at 11:38:18AM -0700, Randy Dunlap wrote:
>> On 04/23/18 07:46, Bryant G. Ly wrote:
>>> This driver is a logical device which provides an
>>> interface between the hypervisor and a management
>>> partition.
>>>
>>> This driver is to be used for the POWER Virtual
>>> Management Channel Virtual Adapter on the PowerVM
>>> platform. It provides both request/response and
>>> async message support through the /dev/ibmvmc node.
>>>
>>> Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
>>> Reviewed-by: Steven Royer <seroyer@linux.vnet.ibm.com>
>>> Reviewed-by: Adam Reznechek <adreznec@linux.vnet.ibm.com>
>>> Tested-by: Taylor Jakobson <tjakobs@us.ibm.com>
>>> Tested-by: Brad Warrum <bwarrum@us.ibm.com>
>>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>> Cc: Arnd Bergmann <arnd@arndb.de>
>>> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>>> Cc: Michael Ellerman <mpe@ellerman.id.au>
>>> ---
>>>  Documentation/ioctl/ioctl-number.txt  |    1 +
>>>  Documentation/misc-devices/ibmvmc.txt |  161 +++
>>>  MAINTAINERS                           |    6 +
>>>  arch/powerpc/include/asm/hvcall.h     |    1 +
>>>  drivers/misc/Kconfig                  |   14 +
>>>  drivers/misc/Makefile                 |    1 +
>>>  drivers/misc/ibmvmc.c                 | 2415 +++++++++++++++++++++++++++++++++
>>>  drivers/misc/ibmvmc.h                 |  209 +++
>>>  8 files changed, 2808 insertions(+)
>>>  create mode 100644 Documentation/misc-devices/ibmvmc.txt
>>>  create mode 100644 drivers/misc/ibmvmc.c
>>>  create mode 100644 drivers/misc/ibmvmc.h
>>
>>> diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-devices/ibmvmc.txt
>>> new file mode 100644
>>> index 0000000..bae1064
>>> --- /dev/null
>>> +++ b/Documentation/misc-devices/ibmvmc.txt
> 
> Aren't we doing new documentation in .rst format instead of .txt?

I am not aware that .rst format is a *requirement* for new documentation.

??

-- 
~Randy
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Re: [PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Randy Dunlap]

On 04/23/18 12:53, Greg KH wrote:
> On Mon, Apr 23, 2018 at 11:38:18AM -0700, Randy Dunlap wrote:
>> On 04/23/18 07:46, Bryant G. Ly wrote:
>>> This driver is a logical device which provides an
>>> interface between the hypervisor and a management
>>> partition.
>>>
>>> This driver is to be used for the POWER Virtual
>>> Management Channel Virtual Adapter on the PowerVM
>>> platform. It provides both request/response and
>>> async message support through the /dev/ibmvmc node.
>>>
>>> Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
>>> Reviewed-by: Steven Royer <seroyer@linux.vnet.ibm.com>
>>> Reviewed-by: Adam Reznechek <adreznec@linux.vnet.ibm.com>
>>> Tested-by: Taylor Jakobson <tjakobs@us.ibm.com>
>>> Tested-by: Brad Warrum <bwarrum@us.ibm.com>
>>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>> Cc: Arnd Bergmann <arnd@arndb.de>
>>> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>>> Cc: Michael Ellerman <mpe@ellerman.id.au>
>>> ---
>>>  Documentation/ioctl/ioctl-number.txt  |    1 +
>>>  Documentation/misc-devices/ibmvmc.txt |  161 +++
>>>  MAINTAINERS                           |    6 +
>>>  arch/powerpc/include/asm/hvcall.h     |    1 +
>>>  drivers/misc/Kconfig                  |   14 +
>>>  drivers/misc/Makefile                 |    1 +
>>>  drivers/misc/ibmvmc.c                 | 2415 +++++++++++++++++++++++++++++++++
>>>  drivers/misc/ibmvmc.h                 |  209 +++
>>>  8 files changed, 2808 insertions(+)
>>>  create mode 100644 Documentation/misc-devices/ibmvmc.txt
>>>  create mode 100644 drivers/misc/ibmvmc.c
>>>  create mode 100644 drivers/misc/ibmvmc.h
>>
>>> diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-devices/ibmvmc.txt
>>> new file mode 100644
>>> index 0000000..bae1064
>>> --- /dev/null
>>> +++ b/Documentation/misc-devices/ibmvmc.txt
> 
> Aren't we doing new documentation in .rst format instead of .txt?

I am not aware that .rst format is a *requirement* for new documentation.

??

-- 
~Randy

Re: [PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Greg KH]

On Mon, Apr 23, 2018 at 02:17:28PM -0700, Randy Dunlap wrote:
> On 04/23/18 12:53, Greg KH wrote:
> > On Mon, Apr 23, 2018 at 11:38:18AM -0700, Randy Dunlap wrote:
> >> On 04/23/18 07:46, Bryant G. Ly wrote:
> >>> This driver is a logical device which provides an
> >>> interface between the hypervisor and a management
> >>> partition.
> >>>
> >>> This driver is to be used for the POWER Virtual
> >>> Management Channel Virtual Adapter on the PowerVM
> >>> platform. It provides both request/response and
> >>> async message support through the /dev/ibmvmc node.
> >>>
> >>> Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
> >>> Reviewed-by: Steven Royer <seroyer@linux.vnet.ibm.com>
> >>> Reviewed-by: Adam Reznechek <adreznec@linux.vnet.ibm.com>
> >>> Tested-by: Taylor Jakobson <tjakobs@us.ibm.com>
> >>> Tested-by: Brad Warrum <bwarrum@us.ibm.com>
> >>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> >>> Cc: Arnd Bergmann <arnd@arndb.de>
> >>> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> >>> Cc: Michael Ellerman <mpe@ellerman.id.au>
> >>> ---
> >>>  Documentation/ioctl/ioctl-number.txt  |    1 +
> >>>  Documentation/misc-devices/ibmvmc.txt |  161 +++
> >>>  MAINTAINERS                           |    6 +
> >>>  arch/powerpc/include/asm/hvcall.h     |    1 +
> >>>  drivers/misc/Kconfig                  |   14 +
> >>>  drivers/misc/Makefile                 |    1 +
> >>>  drivers/misc/ibmvmc.c                 | 2415 +++++++++++++++++++++++++++++++++
> >>>  drivers/misc/ibmvmc.h                 |  209 +++
> >>>  8 files changed, 2808 insertions(+)
> >>>  create mode 100644 Documentation/misc-devices/ibmvmc.txt
> >>>  create mode 100644 drivers/misc/ibmvmc.c
> >>>  create mode 100644 drivers/misc/ibmvmc.h
> >>
> >>> diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-devices/ibmvmc.txt
> >>> new file mode 100644
> >>> index 0000000..bae1064
> >>> --- /dev/null
> >>> +++ b/Documentation/misc-devices/ibmvmc.txt
> > 
> > Aren't we doing new documentation in .rst format instead of .txt?
> 
> I am not aware that .rst format is a *requirement* for new documentation.
> 
> ??

Why wouldn't you create new documentation in that format?  Just saves
the step of having to change it again in the future.

thanks,

greg k-h
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Re: [PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Greg KH]

On Mon, Apr 23, 2018 at 02:17:28PM -0700, Randy Dunlap wrote:
> On 04/23/18 12:53, Greg KH wrote:
> > On Mon, Apr 23, 2018 at 11:38:18AM -0700, Randy Dunlap wrote:
> >> On 04/23/18 07:46, Bryant G. Ly wrote:
> >>> This driver is a logical device which provides an
> >>> interface between the hypervisor and a management
> >>> partition.
> >>>
> >>> This driver is to be used for the POWER Virtual
> >>> Management Channel Virtual Adapter on the PowerVM
> >>> platform. It provides both request/response and
> >>> async message support through the /dev/ibmvmc node.
> >>>
> >>> Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
> >>> Reviewed-by: Steven Royer <seroyer@linux.vnet.ibm.com>
> >>> Reviewed-by: Adam Reznechek <adreznec@linux.vnet.ibm.com>
> >>> Tested-by: Taylor Jakobson <tjakobs@us.ibm.com>
> >>> Tested-by: Brad Warrum <bwarrum@us.ibm.com>
> >>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> >>> Cc: Arnd Bergmann <arnd@arndb.de>
> >>> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> >>> Cc: Michael Ellerman <mpe@ellerman.id.au>
> >>> ---
> >>>  Documentation/ioctl/ioctl-number.txt  |    1 +
> >>>  Documentation/misc-devices/ibmvmc.txt |  161 +++
> >>>  MAINTAINERS                           |    6 +
> >>>  arch/powerpc/include/asm/hvcall.h     |    1 +
> >>>  drivers/misc/Kconfig                  |   14 +
> >>>  drivers/misc/Makefile                 |    1 +
> >>>  drivers/misc/ibmvmc.c                 | 2415 +++++++++++++++++++++++++++++++++
> >>>  drivers/misc/ibmvmc.h                 |  209 +++
> >>>  8 files changed, 2808 insertions(+)
> >>>  create mode 100644 Documentation/misc-devices/ibmvmc.txt
> >>>  create mode 100644 drivers/misc/ibmvmc.c
> >>>  create mode 100644 drivers/misc/ibmvmc.h
> >>
> >>> diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-devices/ibmvmc.txt
> >>> new file mode 100644
> >>> index 0000000..bae1064
> >>> --- /dev/null
> >>> +++ b/Documentation/misc-devices/ibmvmc.txt
> > 
> > Aren't we doing new documentation in .rst format instead of .txt?
> 
> I am not aware that .rst format is a *requirement* for new documentation.
> 
> ??

Why wouldn't you create new documentation in that format?  Just saves
the step of having to change it again in the future.

thanks,

greg k-h

Re: [PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Randy Dunlap]

On 04/24/2018 07:29 AM, Greg KH wrote:
> On Mon, Apr 23, 2018 at 02:17:28PM -0700, Randy Dunlap wrote:
>> On 04/23/18 12:53, Greg KH wrote:
>>> On Mon, Apr 23, 2018 at 11:38:18AM -0700, Randy Dunlap wrote:
>>>> On 04/23/18 07:46, Bryant G. Ly wrote:
>>>>> This driver is a logical device which provides an
>>>>> interface between the hypervisor and a management
>>>>> partition.
>>>>>
>>>>> This driver is to be used for the POWER Virtual
>>>>> Management Channel Virtual Adapter on the PowerVM
>>>>> platform. It provides both request/response and
>>>>> async message support through the /dev/ibmvmc node.
>>>>>
>>>>> Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
>>>>> Reviewed-by: Steven Royer <seroyer@linux.vnet.ibm.com>
>>>>> Reviewed-by: Adam Reznechek <adreznec@linux.vnet.ibm.com>
>>>>> Tested-by: Taylor Jakobson <tjakobs@us.ibm.com>
>>>>> Tested-by: Brad Warrum <bwarrum@us.ibm.com>
>>>>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>>>> Cc: Arnd Bergmann <arnd@arndb.de>
>>>>> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>>>>> Cc: Michael Ellerman <mpe@ellerman.id.au>
>>>>> ---
>>>>>  Documentation/ioctl/ioctl-number.txt  |    1 +
>>>>>  Documentation/misc-devices/ibmvmc.txt |  161 +++
>>>>>  MAINTAINERS                           |    6 +
>>>>>  arch/powerpc/include/asm/hvcall.h     |    1 +
>>>>>  drivers/misc/Kconfig                  |   14 +
>>>>>  drivers/misc/Makefile                 |    1 +
>>>>>  drivers/misc/ibmvmc.c                 | 2415 +++++++++++++++++++++++++++++++++
>>>>>  drivers/misc/ibmvmc.h                 |  209 +++
>>>>>  8 files changed, 2808 insertions(+)
>>>>>  create mode 100644 Documentation/misc-devices/ibmvmc.txt
>>>>>  create mode 100644 drivers/misc/ibmvmc.c
>>>>>  create mode 100644 drivers/misc/ibmvmc.h
>>>>
>>>>> diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-devices/ibmvmc.txt
>>>>> new file mode 100644
>>>>> index 0000000..bae1064
>>>>> --- /dev/null
>>>>> +++ b/Documentation/misc-devices/ibmvmc.txt
>>>
>>> Aren't we doing new documentation in .rst format instead of .txt?
>>
>> I am not aware that .rst format is a *requirement* for new documentation.
>>
>> ??
> 
> Why wouldn't you create new documentation in that format?  Just saves
> the step of having to change it again in the future.

Not everything needs to be in that format.
If a document contains graphics or lots of tables, then sure, use RST.

Do you do kernel Documentation builds yourself?  Do you know how slow they are?

-- 
~Randy
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Re: [PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Randy Dunlap]

On 04/24/2018 07:29 AM, Greg KH wrote:
> On Mon, Apr 23, 2018 at 02:17:28PM -0700, Randy Dunlap wrote:
>> On 04/23/18 12:53, Greg KH wrote:
>>> On Mon, Apr 23, 2018 at 11:38:18AM -0700, Randy Dunlap wrote:
>>>> On 04/23/18 07:46, Bryant G. Ly wrote:
>>>>> This driver is a logical device which provides an
>>>>> interface between the hypervisor and a management
>>>>> partition.
>>>>>
>>>>> This driver is to be used for the POWER Virtual
>>>>> Management Channel Virtual Adapter on the PowerVM
>>>>> platform. It provides both request/response and
>>>>> async message support through the /dev/ibmvmc node.
>>>>>
>>>>> Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
>>>>> Reviewed-by: Steven Royer <seroyer@linux.vnet.ibm.com>
>>>>> Reviewed-by: Adam Reznechek <adreznec@linux.vnet.ibm.com>
>>>>> Tested-by: Taylor Jakobson <tjakobs@us.ibm.com>
>>>>> Tested-by: Brad Warrum <bwarrum@us.ibm.com>
>>>>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>>>> Cc: Arnd Bergmann <arnd@arndb.de>
>>>>> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>>>>> Cc: Michael Ellerman <mpe@ellerman.id.au>
>>>>> ---
>>>>>  Documentation/ioctl/ioctl-number.txt  |    1 +
>>>>>  Documentation/misc-devices/ibmvmc.txt |  161 +++
>>>>>  MAINTAINERS                           |    6 +
>>>>>  arch/powerpc/include/asm/hvcall.h     |    1 +
>>>>>  drivers/misc/Kconfig                  |   14 +
>>>>>  drivers/misc/Makefile                 |    1 +
>>>>>  drivers/misc/ibmvmc.c                 | 2415 +++++++++++++++++++++++++++++++++
>>>>>  drivers/misc/ibmvmc.h                 |  209 +++
>>>>>  8 files changed, 2808 insertions(+)
>>>>>  create mode 100644 Documentation/misc-devices/ibmvmc.txt
>>>>>  create mode 100644 drivers/misc/ibmvmc.c
>>>>>  create mode 100644 drivers/misc/ibmvmc.h
>>>>
>>>>> diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-devices/ibmvmc.txt
>>>>> new file mode 100644
>>>>> index 0000000..bae1064
>>>>> --- /dev/null
>>>>> +++ b/Documentation/misc-devices/ibmvmc.txt
>>>
>>> Aren't we doing new documentation in .rst format instead of .txt?
>>
>> I am not aware that .rst format is a *requirement* for new documentation.
>>
>> ??
> 
> Why wouldn't you create new documentation in that format?  Just saves
> the step of having to change it again in the future.

Not everything needs to be in that format.
If a document contains graphics or lots of tables, then sure, use RST.

Do you do kernel Documentation builds yourself?  Do you know how slow they are?

-- 
~Randy

Re: [PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Linus Walleij]

I don't know why I'm included in review of this driver, but why
not :) it is good to include people.

Thanks for your patch! It looks exciting and complicated,
I like that kind of stuff.

On Mon, Apr 23, 2018 at 4:46 PM, Bryant G. Ly
<bryantly@linux.vnet.ibm.com> wrote:

> This driver is a logical device which provides an
> interface between the hypervisor and a management
> partition.

Please indicate what this management partition is to
be used for, i.e. the intended use case.

> This driver is to be used for the POWER Virtual
> Management Channel Virtual Adapter on the PowerVM
> platform.

Is that virtualization on the PowerPC platform?

> It provides both request/response and
> async message support through the /dev/ibmvmc node.

Is that a character or block device?
I guess block, but it's nice to have some specifics
in the commit message.

> diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-devices/ibmvmc.txt

The document suffers a bit from internal lingo, so it's be great
if you improve it a bit with a style that will be welcoming for newcomers
who have no idea what you are talking about.

I will point out some items below.

> +Description
> +===========
> +
> +The Virtual Management Channel (VMC) is a logical device which provides an
> +interface between the hypervisor and a management partition.

What kind of interface? A bitstream? Message passing interface?
Marshalling of structs? Some specifics would be great.

> This
> +management partition is intended to provide an alternative to HMC-based
> +system management.

Please expand the acronym HMC for the newcomer so we do not need
to look it up, or it looks like the document is only for people who already
know everything about virtualization specifics.

> In the management partition, a Novalink application
> +exists

Is Novalink some kind of product name? In that case, can it be
instead described with some neutral technology name and state
Novalink as an examplf of this type of technology?

> which enables a system administrator to configure the system’s
> +partitioning characteristics

Exemplify "partitioning characteristics", with a sentence in this
vein: "partitioning characteristics such as FOO, BAR and BAZ".

> via a command line interface (CLI) or
> +Representational State Transfer Application (REST).

I understand what CLI is but what is a representational state
transfer application? Is that a fancy name for a GUI application
doing the same thing as a CLI program would do?

> You can also manage the
> +server by using PowerVC

There was PowerVM now there is PowerVC. What are those things
really? PowerVM I guess is virtual machine on PowerPC? What is
PowerVC? Virtual client (guest) in the PowerVM?

This kind of lingo makes the document a hard read for me.

> or other OpenStack solution.

I heard about OpenStack. I have a vague idea about what it is,
do you mean "other virtualization concepts"?

> Support for
> +conventional HMC management of the system may still be provided on a
> +system; however, when an HMC is attached to the system, the VMC
> +interface is disabled by the hypervisor.

The VMC acronym is expanded below, instead expand it at first
instance. The same for HMC (hypervisor management channel I guess?
it is never really explained.)

> +NovaLink runs on a Linux logical partition on a POWER8 or newer processor-
> +based server that is virtualized by PowerVM.

So this information needs to be in the top of the document.

> System configuration,
> +maintenance, and control functions which traditionally require an HMC can
> +be implemented in the Novalink using a combination of HMC to hypervisor
> +interfaces and existing operating system methods. This tool provides

What tool? It is unclear what tool we are referring to here.
A command line tool? A technology? etc.

> a
> +subset of the functions implemented by the HMC and enables basic partition
> +configuration. The set of HMC to hypervisor messages

This makes me think that probably the "h" in HMC stands for "hypervisor"
so now I start to puzzle things together. But it's nicer if you just expand
the acronym the first time you use it.

> supported by the
> +Novalink component

I still haven't figured out what that is, in practice.

> are passed to the hypervisor over a VMC interface, which
> +is defined below.

Maybe some illustration of how HMC, Novalink and VMC work
together would be appropriate?

> +Virtual Management Channel (VMC)
> +A logical device, called the virtual management channel (VMC), is defined
> +for communicating between the Novalink application and the hypervisor.


So is "Novalink" some specific application, as in a proprietary
piece of software or something?

I'm still confused.

> +This device, similar to a VSCSI server device,

What is that acronym now, I get completely confused.

> is presented to a designated
> +management partition as a virtual device and is only presented when the
> +system is not HMC managed.
> +This communication device borrows aspects from both VSCSI and ILLAN devices

Now there is ILLAN too.

> +and is implemented using the CRQ and the RDMA interfaces.

CRQ and RDMA. The RDMA I heard about, I wonder what CRQ is.

At this point the document is referring to so much external a priori
knowledge that I don't have that I don't understand anything at all.

So if this document is meant as an introduction to the technology
for newcomers, it's not working at all, unfortunately.

If some specific domain knowledge is needed to read and
understand the document, you need to state these prerequisites
at the beginning of the document.

Something like: "if you don't know a lot about virtualization already,
then don't even bother trying to read this document".

Yours,
Linus Walleij
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Re: [PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[Linus Walleij]

I don't know why I'm included in review of this driver, but why
not :) it is good to include people.

Thanks for your patch! It looks exciting and complicated,
I like that kind of stuff.

On Mon, Apr 23, 2018 at 4:46 PM, Bryant G. Ly
<bryantly@linux.vnet.ibm.com> wrote:

> This driver is a logical device which provides an
> interface between the hypervisor and a management
> partition.

Please indicate what this management partition is to
be used for, i.e. the intended use case.

> This driver is to be used for the POWER Virtual
> Management Channel Virtual Adapter on the PowerVM
> platform.

Is that virtualization on the PowerPC platform?

> It provides both request/response and
> async message support through the /dev/ibmvmc node.

Is that a character or block device?
I guess block, but it's nice to have some specifics
in the commit message.

> diff --git a/Documentation/misc-devices/ibmvmc.txt b/Documentation/misc-d=
evices/ibmvmc.txt

The document suffers a bit from internal lingo, so it's be great
if you improve it a bit with a style that will be welcoming for newcomers
who have no idea what you are talking about.

I will point out some items below.

> +Description
> +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> +
> +The Virtual Management Channel (VMC) is a logical device which provides =
an
> +interface between the hypervisor and a management partition.

What kind of interface? A bitstream? Message passing interface?
Marshalling of structs? Some specifics would be great.

> This
> +management partition is intended to provide an alternative to HMC-based
> +system management.

Please expand the acronym HMC for the newcomer so we do not need
to look it up, or it looks like the document is only for people who already
know everything about virtualization specifics.

> In the management partition, a Novalink application
> +exists

Is Novalink some kind of product name? In that case, can it be
instead described with some neutral technology name and state
Novalink as an examplf of this type of technology?

> which enables a system administrator to configure the system=E2=80=99s
> +partitioning characteristics

Exemplify "partitioning characteristics", with a sentence in this
vein: "partitioning characteristics such as FOO, BAR and BAZ".

> via a command line interface (CLI) or
> +Representational State Transfer Application (REST).

I understand what CLI is but what is a representational state
transfer application? Is that a fancy name for a GUI application
doing the same thing as a CLI program would do?

> You can also manage the
> +server by using PowerVC

There was PowerVM now there is PowerVC. What are those things
really? PowerVM I guess is virtual machine on PowerPC? What is
PowerVC? Virtual client (guest) in the PowerVM?

This kind of lingo makes the document a hard read for me.

> or other OpenStack solution.

I heard about OpenStack. I have a vague idea about what it is,
do you mean "other virtualization concepts"?

> Support for
> +conventional HMC management of the system may still be provided on a
> +system; however, when an HMC is attached to the system, the VMC
> +interface is disabled by the hypervisor.

The VMC acronym is expanded below, instead expand it at first
instance. The same for HMC (hypervisor management channel I guess?
it is never really explained.)

> +NovaLink runs on a Linux logical partition on a POWER8 or newer processo=
r-
> +based server that is virtualized by PowerVM.

So this information needs to be in the top of the document.

> System configuration,
> +maintenance, and control functions which traditionally require an HMC ca=
n
> +be implemented in the Novalink using a combination of HMC to hypervisor
> +interfaces and existing operating system methods. This tool provides

What tool? It is unclear what tool we are referring to here.
A command line tool? A technology? etc.

> a
> +subset of the functions implemented by the HMC and enables basic partiti=
on
> +configuration. The set of HMC to hypervisor messages

This makes me think that probably the "h" in HMC stands for "hypervisor"
so now I start to puzzle things together. But it's nicer if you just expand
the acronym the first time you use it.

> supported by the
> +Novalink component

I still haven't figured out what that is, in practice.

> are passed to the hypervisor over a VMC interface, which
> +is defined below.

Maybe some illustration of how HMC, Novalink and VMC work
together would be appropriate?

> +Virtual Management Channel (VMC)
> +A logical device, called the virtual management channel (VMC), is define=
d
> +for communicating between the Novalink application and the hypervisor.


So is "Novalink" some specific application, as in a proprietary
piece of software or something?

I'm still confused.

> +This device, similar to a VSCSI server device,

What is that acronym now, I get completely confused.

> is presented to a designated
> +management partition as a virtual device and is only presented when the
> +system is not HMC managed.
> +This communication device borrows aspects from both VSCSI and ILLAN devi=
ces

Now there is ILLAN too.

> +and is implemented using the CRQ and the RDMA interfaces.

CRQ and RDMA. The RDMA I heard about, I wonder what CRQ is.

At this point the document is referring to so much external a priori
knowledge that I don't have that I don't understand anything at all.

So if this document is meant as an introduction to the technology
for newcomers, it's not working at all, unfortunately.

If some specific domain knowledge is needed to read and
understand the document, you need to state these prerequisites
at the beginning of the document.

Something like: "if you don't know a lot about virtualization already,
then don't even bother trying to read this document".

Yours,
Linus Walleij

Re: [PATCH v1 1/1] misc: IBM Virtual Management Channel Driver

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 3969 bytes --]

Hi Bryant,

I love your patch! Perhaps something to improve:

[auto build test WARNING on char-misc/char-misc-testing]
[also build test WARNING on v4.17-rc2 next-20180424]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Bryant-G-Ly/misc-IBM-Virtual-Management-Channel-Driver/20180424-060306
config: powerpc64-allyesconfig (attached as .config)
compiler: powerpc64-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=powerpc64 

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   drivers//misc/ibmvmc.c: In function 'ibmvmc_probe':
>> drivers//misc/ibmvmc.c:2133:5: warning: 'rc' may be used uninitialized in this function [-Wmaybe-uninitialized]
     if (rc == H_RESOURCE)
        ^
   drivers//misc/ibmvmc.c:2111:6: note: 'rc' was declared here
     int rc;
         ^~

vim +/rc +2133 drivers//misc/ibmvmc.c

  2097	
  2098	/**
  2099	 * ibmvmc_init_crq_queue - Init CRQ Queue
  2100	 *
  2101	 * @adapter:	crq_server_adapter struct
  2102	 *
  2103	 * Return:
  2104	 *	0 - Success
  2105	 *	Non-zero - Failure
  2106	 */
  2107	static int ibmvmc_init_crq_queue(struct crq_server_adapter *adapter)
  2108	{
  2109		struct vio_dev *vdev = to_vio_dev(adapter->dev);
  2110		struct crq_queue *queue = &adapter->queue;
  2111		int rc;
  2112		int retrc;
  2113	
  2114		queue->msgs = (struct ibmvmc_crq_msg *)get_zeroed_page(GFP_KERNEL);
  2115	
  2116		if (!queue->msgs)
  2117			goto malloc_failed;
  2118	
  2119		queue->size = PAGE_SIZE / sizeof(*queue->msgs);
  2120	
  2121		queue->msg_token = dma_map_single(adapter->dev, queue->msgs,
  2122						  queue->size * sizeof(*queue->msgs),
  2123						  DMA_BIDIRECTIONAL);
  2124	
  2125		if (dma_mapping_error(adapter->dev, queue->msg_token))
  2126			goto map_failed;
  2127	
  2128		retrc = plpar_hcall_norets(H_REG_CRQ,
  2129					   vdev->unit_address,
  2130					   queue->msg_token, PAGE_SIZE);
  2131		retrc = rc;
  2132	
> 2133		if (rc == H_RESOURCE)
  2134			rc = ibmvmc_reset_crq_queue(adapter);
  2135	
  2136		if (rc == 2) {
  2137			dev_warn(adapter->dev, "Partner adapter not ready\n");
  2138			retrc = 0;
  2139		} else if (rc != 0) {
  2140			dev_err(adapter->dev, "Error %d opening adapter\n", rc);
  2141			goto reg_crq_failed;
  2142		}
  2143	
  2144		queue->cur = 0;
  2145		spin_lock_init(&queue->lock);
  2146	
  2147		tasklet_init(&adapter->work_task, ibmvmc_task, (unsigned long)adapter);
  2148	
  2149		if (request_irq(vdev->irq,
  2150				ibmvmc_handle_event,
  2151				0, "ibmvmc", (void *)adapter) != 0) {
  2152			dev_err(adapter->dev, "couldn't register irq 0x%x\n",
  2153				vdev->irq);
  2154			goto req_irq_failed;
  2155		}
  2156	
  2157		rc = vio_enable_interrupts(vdev);
  2158		if (rc != 0) {
  2159			dev_err(adapter->dev, "Error %d enabling interrupts!!!\n", rc);
  2160			goto req_irq_failed;
  2161		}
  2162	
  2163		return retrc;
  2164	
  2165	req_irq_failed:
  2166		/* Cannot have any work since we either never got our IRQ registered,
  2167		 * or never got interrupts enabled
  2168		 */
  2169		tasklet_kill(&adapter->work_task);
  2170		h_free_crq(vdev->unit_address);
  2171	reg_crq_failed:
  2172		dma_unmap_single(adapter->dev,
  2173				 queue->msg_token,
  2174				 queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);
  2175	map_failed:
  2176		free_page((unsigned long)queue->msgs);
  2177	malloc_failed:
  2178		return -ENOMEM;
  2179	}
  2180	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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