1 files changed, 399 insertions, 0 deletions
diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c
new file mode 100644
index 000000000..c08a6cfd1
--- /dev/null
+++ b/drivers/uio/uio_hv_generic.c
@@ -0,0 +1,399 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * uio_hv_generic - generic UIO driver for VMBus
+ *
+ * Copyright (c) 2013-2016 Brocade Communications Systems, Inc.
+ * Copyright (c) 2016, Microsoft Corporation.
+ *
+ * Since the driver does not declare any device ids, you must allocate
+ * id and bind the device to the driver yourself.  For example:
+ *
+ * Associate Network GUID with UIO device
+ * # echo "f8615163-df3e-46c5-913f-f2d2f965ed0e" \
+ *    > /sys/bus/vmbus/drivers/uio_hv_generic/new_id
+ * Then rebind
+ * # echo -n "ed963694-e847-4b2a-85af-bc9cfc11d6f3" \
+ *    > /sys/bus/vmbus/drivers/hv_netvsc/unbind
+ * # echo -n "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	"0.02.1"
+#define DRIVER_AUTHOR	"Stephen Hemminger <sthemmin at microsoft.com>"
+#define DRIVER_DESC	"Generic UIO driver for VMBus devices"
+
+#define HV_RING_SIZE	 512	/* pages */
+#define SEND_BUFFER_SIZE (16 * 1024 * 1024)
+#define RECV_BUFFER_SIZE (31 * 1024 * 1024)
+
+/*
+ * 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,
+	RECV_BUF_MAP,
+	SEND_BUF_MAP
+};
+
+struct hv_uio_private_data {
+	struct uio_info info;
+	struct hv_device *device;
+	atomic_t refcnt;
+
+	void	*recv_buf;
+	struct vmbus_gpadl recv_gpadl;
+	char	recv_name[32];	/* "recv_4294967295" */
+
+	void	*send_buf;
+	struct vmbus_gpadl send_gpadl;
+	char	send_name[32];
+};
+
+/*
+ * 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 vmbus_channel *chan = context;
+	struct hv_device *hv_dev = chan->device_obj;
+	struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev);
+
+	chan->inbound.ring_buffer->interrupt_mask = 1;
+	virt_mb();
+
+	uio_event_notify(&pdata->info);
+}
+
+/*
+ * Callback from vmbus_event when channel is rescinded.
+ */
+static void hv_uio_rescind(struct vmbus_channel *channel)
+{
+	struct hv_device *hv_dev = channel->primary_channel->device_obj;
+	struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev);
+
+	/*
+	 * Turn off the interrupt file handle
+	 * Next read for event will return -EIO
+	 */
+	pdata->info.irq = 0;
+
+	/* Wake up reader */
+	uio_event_notify(&pdata->info);
+}
+
+/* Sysfs API to allow mmap of the ring buffers
+ * The ring buffer is allocated as contiguous memory by vmbus_open
+ */
+static int hv_uio_ring_mmap(struct file *filp, struct kobject *kobj,
+			    struct bin_attribute *attr,
+			    struct vm_area_struct *vma)
+{
+	struct vmbus_channel *channel
+		= container_of(kobj, struct vmbus_channel, kobj);
+	void *ring_buffer = page_address(channel->ringbuffer_page);
+
+	if (channel->state != CHANNEL_OPENED_STATE)
+		return -ENODEV;
+
+	return vm_iomap_memory(vma, virt_to_phys(ring_buffer),
+			       channel->ringbuffer_pagecount << PAGE_SHIFT);
+}
+
+static const struct bin_attribute ring_buffer_bin_attr = {
+	.attr = {
+		.name = "ring",
+		.mode = 0600,
+	},
+	.size = 2 * HV_RING_SIZE * PAGE_SIZE,
+	.mmap = hv_uio_ring_mmap,
+};
+
+/* Callback from VMBUS subsystem when new channel created. */
+static void
+hv_uio_new_channel(struct vmbus_channel *new_sc)
+{
+	struct hv_device *hv_dev = new_sc->primary_channel->device_obj;
+	struct device *device = &hv_dev->device;
+	const size_t ring_bytes = HV_RING_SIZE * PAGE_SIZE;
+	int ret;
+
+	/* Create host communication ring */
+	ret = vmbus_open(new_sc, ring_bytes, ring_bytes, NULL, 0,
+			 hv_uio_channel_cb, new_sc);
+	if (ret) {
+		dev_err(device, "vmbus_open subchannel failed: %d\n", ret);
+		return;
+	}
+
+	/* Disable interrupts on sub channel */
+	new_sc->inbound.ring_buffer->interrupt_mask = 1;
+	set_channel_read_mode(new_sc, HV_CALL_ISR);
+
+	ret = sysfs_create_bin_file(&new_sc->kobj, &ring_buffer_bin_attr);
+	if (ret) {
+		dev_err(device, "sysfs create ring bin file failed; %d\n", ret);
+		vmbus_close(new_sc);
+	}
+}
+
+/* free the reserved buffers for send and receive */
+static void
+hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata)
+{
+	if (pdata->send_gpadl.gpadl_handle) {
+		vmbus_teardown_gpadl(dev->channel, &pdata->send_gpadl);
+		vfree(pdata->send_buf);
+	}
+
+	if (pdata->recv_gpadl.gpadl_handle) {
+		vmbus_teardown_gpadl(dev->channel, &pdata->recv_gpadl);
+		vfree(pdata->recv_buf);
+	}
+}
+
+/* VMBus primary channel is opened on first use */
+static int
+hv_uio_open(struct uio_info *info, struct inode *inode)
+{
+	struct hv_uio_private_data *pdata
+		= container_of(info, struct hv_uio_private_data, info);
+	struct hv_device *dev = pdata->device;
+	int ret;
+
+	if (atomic_inc_return(&pdata->refcnt) != 1)
+		return 0;
+
+	vmbus_set_chn_rescind_callback(dev->channel, hv_uio_rescind);
+	vmbus_set_sc_create_callback(dev->channel, hv_uio_new_channel);
+
+	ret = vmbus_connect_ring(dev->channel,
+				 hv_uio_channel_cb, dev->channel);
+	if (ret == 0)
+		dev->channel->inbound.ring_buffer->interrupt_mask = 1;
+	else
+		atomic_dec(&pdata->refcnt);
+
+	return ret;
+}
+
+/* VMBus primary channel is closed on last close */
+static int
+hv_uio_release(struct uio_info *info, struct inode *inode)
+{
+	struct hv_uio_private_data *pdata
+		= container_of(info, struct hv_uio_private_data, info);
+	struct hv_device *dev = pdata->device;
+	int ret = 0;
+
+	if (atomic_dec_and_test(&pdata->refcnt))
+		ret = vmbus_disconnect_ring(dev->channel);
+
+	return ret;
+}
+
+static int
+hv_uio_probe(struct hv_device *dev,
+	     const struct hv_vmbus_device_id *dev_id)
+{
+	struct vmbus_channel *channel = dev->channel;
+	struct hv_uio_private_data *pdata;
+	void *ring_buffer;
+	int ret;
+
+	/* Communicating with host has to be via shared memory not hypercall */
+	if (!channel->offermsg.monitor_allocated) {
+		dev_err(&dev->device, "vmbus channel requires hypercall\n");
+		return -ENOTSUPP;
+	}
+
+	pdata = devm_kzalloc(&dev->device, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+
+	ret = vmbus_alloc_ring(channel, HV_RING_SIZE * PAGE_SIZE,
+			       HV_RING_SIZE * PAGE_SIZE);
+	if (ret)
+		return ret;
+
+	set_channel_read_mode(channel, HV_CALL_ISR);
+
+	/* Fill general uio info */
+	pdata->info.name = "uio_hv_generic";
+	pdata->info.version = DRIVER_VERSION;
+	pdata->info.irqcontrol = hv_uio_irqcontrol;
+	pdata->info.open = hv_uio_open;
+	pdata->info.release = hv_uio_release;
+	pdata->info.irq = UIO_IRQ_CUSTOM;
+	atomic_set(&pdata->refcnt, 0);
+
+	/* mem resources */
+	pdata->info.mem[TXRX_RING_MAP].name = "txrx_rings";
+	ring_buffer = page_address(channel->ringbuffer_page);
+	pdata->info.mem[TXRX_RING_MAP].addr
+		= (uintptr_t)virt_to_phys(ring_buffer);
+	pdata->info.mem[TXRX_RING_MAP].size
+		= channel->ringbuffer_pagecount << PAGE_SHIFT;
+	pdata->info.mem[TXRX_RING_MAP].memtype = UIO_MEM_IOVA;
+
+	pdata->info.mem[INT_PAGE_MAP].name = "int_page";
+	pdata->info.mem[INT_PAGE_MAP].addr
+		= (uintptr_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_page";
+	pdata->info.mem[MON_PAGE_MAP].addr
+		= (uintptr_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->recv_buf = vzalloc(RECV_BUFFER_SIZE);
+	if (pdata->recv_buf == NULL) {
+		ret = -ENOMEM;
+		goto fail_free_ring;
+	}
+
+	ret = vmbus_establish_gpadl(channel, pdata->recv_buf,
+				    RECV_BUFFER_SIZE, &pdata->recv_gpadl);
+	if (ret) {
+		vfree(pdata->recv_buf);
+		goto fail_close;
+	}
+
+	/* put Global Physical Address Label in name */
+	snprintf(pdata->recv_name, sizeof(pdata->recv_name),
+		 "recv:%u", pdata->recv_gpadl.gpadl_handle);
+	pdata->info.mem[RECV_BUF_MAP].name = pdata->recv_name;
+	pdata->info.mem[RECV_BUF_MAP].addr
+		= (uintptr_t)pdata->recv_buf;
+	pdata->info.mem[RECV_BUF_MAP].size = RECV_BUFFER_SIZE;
+	pdata->info.mem[RECV_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
+
+	pdata->send_buf = vzalloc(SEND_BUFFER_SIZE);
+	if (pdata->send_buf == NULL) {
+		ret = -ENOMEM;
+		goto fail_close;
+	}
+
+	ret = vmbus_establish_gpadl(channel, pdata->send_buf,
+				    SEND_BUFFER_SIZE, &pdata->send_gpadl);
+	if (ret) {
+		vfree(pdata->send_buf);
+		goto fail_close;
+	}
+
+	snprintf(pdata->send_name, sizeof(pdata->send_name),
+		 "send:%u", pdata->send_gpadl.gpadl_handle);
+	pdata->info.mem[SEND_BUF_MAP].name = pdata->send_name;
+	pdata->info.mem[SEND_BUF_MAP].addr
+		= (uintptr_t)pdata->send_buf;
+	pdata->info.mem[SEND_BUF_MAP].size = SEND_BUFFER_SIZE;
+	pdata->info.mem[SEND_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
+
+	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;
+	}
+
+	ret = sysfs_create_bin_file(&channel->kobj, &ring_buffer_bin_attr);
+	if (ret)
+		dev_notice(&dev->device,
+			   "sysfs create ring bin file failed; %d\n", ret);
+
+	hv_set_drvdata(dev, pdata);
+
+	return 0;
+
+fail_close:
+	hv_uio_cleanup(dev, pdata);
+fail_free_ring:
+	vmbus_free_ring(dev->channel);
+
+	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;
+
+	sysfs_remove_bin_file(&dev->channel->kobj, &ring_buffer_bin_attr);
+	uio_unregister_device(&pdata->info);
+	hv_uio_cleanup(dev, pdata);
+
+	vmbus_free_ring(dev->channel);
+	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);