5 files changed, 230 insertions, 0 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index b0fee8c45135..d19faf724ac6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5852,6 +5852,7 @@ F:	drivers/input/serio/hyperv-keyboard.c
 F:      drivers/pci/host/pci-hyperv.c
 F:      drivers/net/hyperv/
 F:      drivers/scsi/storvsc_drv.c
+F:      drivers/uio/uio_hv_generic.c
 F:      drivers/video/fbdev/hyperv_fb.c
 F:      include/linux/hyperv.h
 F:      tools/hv/
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 78e6368a4423..6ce8b874e833 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -39,6 +39,7 @@ struct vmbus_connection vmbus_connection = {
         .conn_state             = DISCONNECTED,
         .next_gpadl_handle      = ATOMIC_INIT(0xE1E10),
 };
+EXPORT_SYMBOL_GPL(vmbus_connection);
 
 /*
  * Negotiated protocol version with the host.
diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig
index 52c98ce1b6fe..7e8dc78a9796 100644
--- a/drivers/uio/Kconfig
+++ b/drivers/uio/Kconfig
@@ -155,4 +155,13 @@ config UIO_MF624
 
           If you compile this as a module, it will be called uio_mf624.
 
+config UIO_HV_GENERIC
+        tristate "Generic driver for Hyper-V VMBus"
+        depends on HYPERV
+        help
+          Generic driver that you can bind, dynamically, to any
+          Hyper-V VMBus device. It is useful to provide direct access
+          to network and storage devices from userspace.
+
+          If you compile this as a module, it will be called uio_hv_generic.
 endif
diff --git a/drivers/uio/Makefile b/drivers/uio/Makefile
index 8560dad52d0f..e9663bb8a4c7 100644
--- a/drivers/uio/Makefile
+++ b/drivers/uio/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_UIO_NETX)	+= uio_netx.o
 obj-$(CONFIG_UIO_PRUSS)         += uio_pruss.o
 obj-$(CONFIG_UIO_MF624)         += uio_mf624.o
 obj-$(CONFIG_UIO_FSL_ELBC_GPCM) += uio_fsl_elbc_gpcm.o
+obj-$(CONFIG_UIO_HV_GENERIC)    += uio_hv_generic.o
diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c
new file mode 100644
index 000000000000..ad3ab5805ad8
--- /dev/null
+++ b/drivers/uio/uio_hv_generic.c
@@ -0,0 +1,218 @@
+/*
+ * uio_hv_generic - generic UIO driver for VMBus
+ *
+ * Copyright (c) 2013-2016 Brocade Communications Systems, Inc.
+ * Copyright (c) 2016, Microsoft Corporation.
+ *
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ *
+ * Since the driver does not declare any device ids, you must allocate
+ * id and bind the device to the driver yourself.  For example:
+ *
+ * # echo "f8615163-df3e-46c5-913f-f2d2f965ed0e" \
+ *    > /sys/bus/vmbus/drivers/uio_hv_generic
+ * # echo -n vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3 \
+ *    > /sys/bus/vmbus/drivers/hv_netvsc/unbind
+ * # echo -n vmbus-ed963694-e847-4b2a-85af-bc9cfc11d6f3 \
+ *    > /sys/bus/vmbus/drivers/uio_hv_generic/bind
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/uio_driver.h>
+#include <linux/netdevice.h>
+#include <linux/if_ether.h>
+#include <linux/skbuff.h>
+#include <linux/hyperv.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+
+#include "../hv/hyperv_vmbus.h"
+
+#define DRIVER_VERSION  "0.02.0"
+#define DRIVER_AUTHOR   "Stephen Hemminger <sthemmin at microsoft.com>"
+#define DRIVER_DESC     "Generic UIO driver for VMBus devices"
+
+/*
+ * List of resources to be mapped to user space
+ * can be extended up to MAX_UIO_MAPS(5) items
+ */
+enum hv_uio_map {
+        TXRX_RING_MAP = 0,
+        INT_PAGE_MAP,
+        MON_PAGE_MAP,
+};
+
+#define HV_RING_SIZE    512
+
+struct hv_uio_private_data {
+        struct uio_info info;
+        struct hv_device *device;
+};
+
+static int
+hv_uio_mmap(struct uio_info *info, struct vm_area_struct *vma)
+{
+        int mi;
+
+        if (vma->vm_pgoff >= MAX_UIO_MAPS)
+                return -EINVAL;
+
+        if (info->mem[vma->vm_pgoff].size == 0)
+                return -EINVAL;
+
+        mi = (int)vma->vm_pgoff;
+
+        return remap_pfn_range(vma, vma->vm_start,
+                        virt_to_phys((void *)info->mem[mi].addr) >> PAGE_SHIFT,
+                        vma->vm_end - vma->vm_start, vma->vm_page_prot);
+}
+
+/*
+ * This is the irqcontrol callback to be registered to uio_info.
+ * It can be used to disable/enable interrupt from user space processes.
+ *
+ * @param info
+ *  pointer to uio_info.
+ * @param irq_state
+ *  state value. 1 to enable interrupt, 0 to disable interrupt.
+ */
+static int
+hv_uio_irqcontrol(struct uio_info *info, s32 irq_state)
+{
+        struct hv_uio_private_data *pdata = info->priv;
+        struct hv_device *dev = pdata->device;
+
+        dev->channel->inbound.ring_buffer->interrupt_mask = !irq_state;
+        virt_mb();
+
+        return 0;
+}
+
+/*
+ * Callback from vmbus_event when something is in inbound ring.
+ */
+static void hv_uio_channel_cb(void *context)
+{
+        struct hv_uio_private_data *pdata = context;
+        struct hv_device *dev = pdata->device;
+
+        dev->channel->inbound.ring_buffer->interrupt_mask = 1;
+        virt_mb();
+
+        uio_event_notify(&pdata->info);
+}
+
+static int
+hv_uio_probe(struct hv_device *dev,
+             const struct hv_vmbus_device_id *dev_id)
+{
+        struct hv_uio_private_data *pdata;
+        int ret;
+
+        pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
+        if (!pdata)
+                return -ENOMEM;
+
+        ret = vmbus_open(dev->channel, HV_RING_SIZE * PAGE_SIZE,
+                         HV_RING_SIZE * PAGE_SIZE, NULL, 0,
+                         hv_uio_channel_cb, pdata);
+        if (ret)
+                goto fail;
+
+        dev->channel->inbound.ring_buffer->interrupt_mask = 1;
+        dev->channel->batched_reading = false;
+
+        /* Fill general uio info */
+        pdata->info.name = "uio_hv_generic";
+        pdata->info.version = DRIVER_VERSION;
+        pdata->info.irqcontrol = hv_uio_irqcontrol;
+        pdata->info.mmap = hv_uio_mmap;
+        pdata->info.irq = UIO_IRQ_CUSTOM;
+
+        /* mem resources */
+        pdata->info.mem[TXRX_RING_MAP].name = "txrx_rings";
+        pdata->info.mem[TXRX_RING_MAP].addr
+                = (phys_addr_t)dev->channel->ringbuffer_pages;
+        pdata->info.mem[TXRX_RING_MAP].size
+                = dev->channel->ringbuffer_pagecount * PAGE_SIZE;
+        pdata->info.mem[TXRX_RING_MAP].memtype = UIO_MEM_LOGICAL;
+
+        pdata->info.mem[INT_PAGE_MAP].name = "int_page";
+        pdata->info.mem[INT_PAGE_MAP].addr =
+                (phys_addr_t)vmbus_connection.int_page;
+        pdata->info.mem[INT_PAGE_MAP].size = PAGE_SIZE;
+        pdata->info.mem[INT_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
+
+        pdata->info.mem[MON_PAGE_MAP].name = "monitor_pages";
+        pdata->info.mem[MON_PAGE_MAP].addr =
+                (phys_addr_t)vmbus_connection.monitor_pages[1];
+        pdata->info.mem[MON_PAGE_MAP].size = PAGE_SIZE;
+        pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
+
+        pdata->info.priv = pdata;
+        pdata->device = dev;
+
+        ret = uio_register_device(&dev->device, &pdata->info);
+        if (ret) {
+                dev_err(&dev->device, "hv_uio register failed\n");
+                goto fail_close;
+        }
+
+        hv_set_drvdata(dev, pdata);
+
+        return 0;
+
+fail_close:
+        vmbus_close(dev->channel);
+fail:
+        kfree(pdata);
+
+        return ret;
+}
+
+static int
+hv_uio_remove(struct hv_device *dev)
+{
+        struct hv_uio_private_data *pdata = hv_get_drvdata(dev);
+
+        if (!pdata)
+                return 0;
+
+        uio_unregister_device(&pdata->info);
+        hv_set_drvdata(dev, NULL);
+        vmbus_close(dev->channel);
+        kfree(pdata);
+        return 0;
+}
+
+static struct hv_driver hv_uio_drv = {
+        .name = "uio_hv_generic",
+        .id_table = NULL, /* only dynamic id's */
+        .probe = hv_uio_probe,
+        .remove = hv_uio_remove,
+};
+
+static int __init
+hyperv_module_init(void)
+{
+        return vmbus_driver_register(&hv_uio_drv);
+}
+
+static void __exit
+hyperv_module_exit(void)
+{
+        vmbus_driver_unregister(&hv_uio_drv);
+}
+
+module_init(hyperv_module_init);
+module_exit(hyperv_module_exit);
+
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);