LXR linux/drivers/uio/uio_hv

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * uio_hv_generic - generic UIO driver for VMBus
   4 *
   5 * Copyright (c) 2013-2016 Brocade Communications Systems, Inc.
   6 * Copyright (c) 2016, Microsoft Corporation.
   7 *
   8 * Since the driver does not declare any device ids, you must allocate
   9 * id and bind the device to the driver yourself.  For example:
  10 *
  11 * Associate Network GUID with UIO device
  12 * # echo "f8615163-df3e-46c5-913f-f2d2f965ed0e" \
  13 *    > /sys/bus/vmbus/drivers/uio_hv_generic/new_id
  14 * Then rebind
  15 * # echo -n "ed963694-e847-4b2a-85af-bc9cfc11d6f3" \
  16 *    > /sys/bus/vmbus/drivers/hv_netvsc/unbind
  17 * # echo -n "ed963694-e847-4b2a-85af-bc9cfc11d6f3" \
  18 *    > /sys/bus/vmbus/drivers/uio_hv_generic/bind
  19 */
  20#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  21
  22#include <linux/device.h>
  23#include <linux/kernel.h>
  24#include <linux/module.h>
  25#include <linux/uio_driver.h>
  26#include <linux/netdevice.h>
  27#include <linux/if_ether.h>
  28#include <linux/skbuff.h>
  29#include <linux/hyperv.h>
  30#include <linux/vmalloc.h>
  31#include <linux/slab.h>
  32
  33#include "../hv/hyperv_vmbus.h"
  34
  35#define DRIVER_VERSION  "0.02.1"
  36#define DRIVER_AUTHOR   "Stephen Hemminger <sthemmin at microsoft.com>"
  37#define DRIVER_DESC     "Generic UIO driver for VMBus devices"
  38
  39#define HV_RING_SIZE     512    /* pages */
  40#define SEND_BUFFER_SIZE (16 * 1024 * 1024)
  41#define RECV_BUFFER_SIZE (31 * 1024 * 1024)
  42
  43/*
  44 * List of resources to be mapped to user space
  45 * can be extended up to MAX_UIO_MAPS(5) items
  46 */
  47enum hv_uio_map {
  48        TXRX_RING_MAP = 0,
  49        INT_PAGE_MAP,
  50        MON_PAGE_MAP,
  51        RECV_BUF_MAP,
  52        SEND_BUF_MAP
  53};
  54
  55struct hv_uio_private_data {
  56        struct uio_info info;
  57        struct hv_device *device;
  58        atomic_t refcnt;
  59
  60        void    *recv_buf;
  61        u32     recv_gpadl;
  62        char    recv_name[32];  /* "recv_4294967295" */
  63
  64        void    *send_buf;
  65        u32     send_gpadl;
  66        char    send_name[32];
  67};
  68
  69/*
  70 * This is the irqcontrol callback to be registered to uio_info.
  71 * It can be used to disable/enable interrupt from user space processes.
  72 *
  73 * @param info
  74 *  pointer to uio_info.
  75 * @param irq_state
  76 *  state value. 1 to enable interrupt, 0 to disable interrupt.
  77 */
  78static int
  79hv_uio_irqcontrol(struct uio_info *info, s32 irq_state)
  80{
  81        struct hv_uio_private_data *pdata = info->priv;
  82        struct hv_device *dev = pdata->device;
  83
  84        dev->channel->inbound.ring_buffer->interrupt_mask = !irq_state;
  85        virt_mb();
  86
  87        return 0;
  88}
  89
  90/*
  91 * Callback from vmbus_event when something is in inbound ring.
  92 */
  93static void hv_uio_channel_cb(void *context)
  94{
  95        struct vmbus_channel *chan = context;
  96        struct hv_device *hv_dev = chan->device_obj;
  97        struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev);
  98
  99        chan->inbound.ring_buffer->interrupt_mask = 1;
 100        virt_mb();
 101
 102        uio_event_notify(&pdata->info);
 103}
 104
 105/*
 106 * Callback from vmbus_event when channel is rescinded.
 107 */
 108static void hv_uio_rescind(struct vmbus_channel *channel)
 109{
 110        struct hv_device *hv_dev = channel->primary_channel->device_obj;
 111        struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev);
 112
 113        /*
 114         * Turn off the interrupt file handle
 115         * Next read for event will return -EIO
 116         */
 117        pdata->info.irq = 0;
 118
 119        /* Wake up reader */
 120        uio_event_notify(&pdata->info);
 121}
 122
 123/* Sysfs API to allow mmap of the ring buffers
 124 * The ring buffer is allocated as contiguous memory by vmbus_open
 125 */
 126static int hv_uio_ring_mmap(struct file *filp, struct kobject *kobj,
 127                            struct bin_attribute *attr,
 128                            struct vm_area_struct *vma)
 129{
 130        struct vmbus_channel *channel
 131                = container_of(kobj, struct vmbus_channel, kobj);
 132        void *ring_buffer = page_address(channel->ringbuffer_page);
 133
 134        if (channel->state != CHANNEL_OPENED_STATE)
 135                return -ENODEV;
 136
 137        return vm_iomap_memory(vma, virt_to_phys(ring_buffer),
 138                               channel->ringbuffer_pagecount << PAGE_SHIFT);
 139}
 140
 141static const struct bin_attribute ring_buffer_bin_attr = {
 142        .attr = {
 143                .name = "ring",
 144                .mode = 0600,
 145        },
 146        .size = 2 * HV_RING_SIZE * PAGE_SIZE,
 147        .mmap = hv_uio_ring_mmap,
 148};
 149
 150/* Callback from VMBUS subsystem when new channel created. */
 151static void
 152hv_uio_new_channel(struct vmbus_channel *new_sc)
 153{
 154        struct hv_device *hv_dev = new_sc->primary_channel->device_obj;
 155        struct device *device = &hv_dev->device;
 156        const size_t ring_bytes = HV_RING_SIZE * PAGE_SIZE;
 157        int ret;
 158
 159        /* Create host communication ring */
 160        ret = vmbus_open(new_sc, ring_bytes, ring_bytes, NULL, 0,
 161                         hv_uio_channel_cb, new_sc);
 162        if (ret) {
 163                dev_err(device, "vmbus_open subchannel failed: %d\n", ret);
 164                return;
 165        }
 166
 167        /* Disable interrupts on sub channel */
 168        new_sc->inbound.ring_buffer->interrupt_mask = 1;
 169        set_channel_read_mode(new_sc, HV_CALL_ISR);
 170
 171        ret = sysfs_create_bin_file(&new_sc->kobj, &ring_buffer_bin_attr);
 172        if (ret) {
 173                dev_err(device, "sysfs create ring bin file failed; %d\n", ret);
 174                vmbus_close(new_sc);
 175        }
 176}
 177
 178/* free the reserved buffers for send and receive */
 179static void
 180hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata)
 181{
 182        if (pdata->send_gpadl) {
 183                vmbus_teardown_gpadl(dev->channel, pdata->send_gpadl);
 184                pdata->send_gpadl = 0;
 185                vfree(pdata->send_buf);
 186        }
 187
 188        if (pdata->recv_gpadl) {
 189                vmbus_teardown_gpadl(dev->channel, pdata->recv_gpadl);
 190                pdata->recv_gpadl = 0;
 191                vfree(pdata->recv_buf);
 192        }
 193}
 194
 195/* VMBus primary channel is opened on first use */
 196static int
 197hv_uio_open(struct uio_info *info, struct inode *inode)
 198{
 199        struct hv_uio_private_data *pdata
 200                = container_of(info, struct hv_uio_private_data, info);
 201        struct hv_device *dev = pdata->device;
 202        int ret;
 203
 204        if (atomic_inc_return(&pdata->refcnt) != 1)
 205                return 0;
 206
 207        vmbus_set_chn_rescind_callback(dev->channel, hv_uio_rescind);
 208        vmbus_set_sc_create_callback(dev->channel, hv_uio_new_channel);
 209
 210        ret = vmbus_connect_ring(dev->channel,
 211                                 hv_uio_channel_cb, dev->channel);
 212        if (ret == 0)
 213                dev->channel->inbound.ring_buffer->interrupt_mask = 1;
 214        else
 215                atomic_dec(&pdata->refcnt);
 216
 217        return ret;
 218}
 219
 220/* VMBus primary channel is closed on last close */
 221static int
 222hv_uio_release(struct uio_info *info, struct inode *inode)
 223{
 224        struct hv_uio_private_data *pdata
 225                = container_of(info, struct hv_uio_private_data, info);
 226        struct hv_device *dev = pdata->device;
 227        int ret = 0;
 228
 229        if (atomic_dec_and_test(&pdata->refcnt))
 230                ret = vmbus_disconnect_ring(dev->channel);
 231
 232        return ret;
 233}
 234
 235static int
 236hv_uio_probe(struct hv_device *dev,
 237             const struct hv_vmbus_device_id *dev_id)
 238{
 239        struct vmbus_channel *channel = dev->channel;
 240        struct hv_uio_private_data *pdata;
 241        void *ring_buffer;
 242        int ret;
 243
 244        /* Communicating with host has to be via shared memory not hypercall */
 245        if (!channel->offermsg.monitor_allocated) {
 246                dev_err(&dev->device, "vmbus channel requires hypercall\n");
 247                return -ENOTSUPP;
 248        }
 249
 250        pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
 251        if (!pdata)
 252                return -ENOMEM;
 253
 254        ret = vmbus_alloc_ring(channel, HV_RING_SIZE * PAGE_SIZE,
 255                               HV_RING_SIZE * PAGE_SIZE);
 256        if (ret)
 257                goto fail;
 258
 259        set_channel_read_mode(channel, HV_CALL_ISR);
 260
 261        /* Fill general uio info */
 262        pdata->info.name = "uio_hv_generic";
 263        pdata->info.version = DRIVER_VERSION;
 264        pdata->info.irqcontrol = hv_uio_irqcontrol;
 265        pdata->info.open = hv_uio_open;
 266        pdata->info.release = hv_uio_release;
 267        pdata->info.irq = UIO_IRQ_CUSTOM;
 268        atomic_set(&pdata->refcnt, 0);
 269
 270        /* mem resources */
 271        pdata->info.mem[TXRX_RING_MAP].name = "txrx_rings";
 272        ring_buffer = page_address(channel->ringbuffer_page);
 273        pdata->info.mem[TXRX_RING_MAP].addr
 274                = (uintptr_t)virt_to_phys(ring_buffer);
 275        pdata->info.mem[TXRX_RING_MAP].size
 276                = channel->ringbuffer_pagecount << PAGE_SHIFT;
 277        pdata->info.mem[TXRX_RING_MAP].memtype = UIO_MEM_IOVA;
 278
 279        pdata->info.mem[INT_PAGE_MAP].name = "int_page";
 280        pdata->info.mem[INT_PAGE_MAP].addr
 281                = (uintptr_t)vmbus_connection.int_page;
 282        pdata->info.mem[INT_PAGE_MAP].size = PAGE_SIZE;
 283        pdata->info.mem[INT_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
 284
 285        pdata->info.mem[MON_PAGE_MAP].name = "monitor_page";
 286        pdata->info.mem[MON_PAGE_MAP].addr
 287                = (uintptr_t)vmbus_connection.monitor_pages[1];
 288        pdata->info.mem[MON_PAGE_MAP].size = PAGE_SIZE;
 289        pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
 290
 291        pdata->recv_buf = vzalloc(RECV_BUFFER_SIZE);
 292        if (pdata->recv_buf == NULL) {
 293                ret = -ENOMEM;
 294                goto fail_close;
 295        }
 296
 297        ret = vmbus_establish_gpadl(channel, pdata->recv_buf,
 298                                    RECV_BUFFER_SIZE, &pdata->recv_gpadl);
 299        if (ret)
 300                goto fail_close;
 301
 302        /* put Global Physical Address Label in name */
 303        snprintf(pdata->recv_name, sizeof(pdata->recv_name),
 304                 "recv:%u", pdata->recv_gpadl);
 305        pdata->info.mem[RECV_BUF_MAP].name = pdata->recv_name;
 306        pdata->info.mem[RECV_BUF_MAP].addr
 307                = (uintptr_t)pdata->recv_buf;
 308        pdata->info.mem[RECV_BUF_MAP].size = RECV_BUFFER_SIZE;
 309        pdata->info.mem[RECV_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
 310
 311        pdata->send_buf = vzalloc(SEND_BUFFER_SIZE);
 312        if (pdata->send_buf == NULL) {
 313                ret = -ENOMEM;
 314                goto fail_close;
 315        }
 316
 317        ret = vmbus_establish_gpadl(channel, pdata->send_buf,
 318                                    SEND_BUFFER_SIZE, &pdata->send_gpadl);
 319        if (ret)
 320                goto fail_close;
 321
 322        snprintf(pdata->send_name, sizeof(pdata->send_name),
 323                 "send:%u", pdata->send_gpadl);
 324        pdata->info.mem[SEND_BUF_MAP].name = pdata->send_name;
 325        pdata->info.mem[SEND_BUF_MAP].addr
 326                = (uintptr_t)pdata->send_buf;
 327        pdata->info.mem[SEND_BUF_MAP].size = SEND_BUFFER_SIZE;
 328        pdata->info.mem[SEND_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
 329
 330        pdata->info.priv = pdata;
 331        pdata->device = dev;
 332
 333        ret = uio_register_device(&dev->device, &pdata->info);
 334        if (ret) {
 335                dev_err(&dev->device, "hv_uio register failed\n");
 336                goto fail_close;
 337        }
 338
 339        ret = sysfs_create_bin_file(&channel->kobj, &ring_buffer_bin_attr);
 340        if (ret)
 341                dev_notice(&dev->device,
 342                           "sysfs create ring bin file failed; %d\n", ret);
 343
 344        hv_set_drvdata(dev, pdata);
 345
 346        return 0;
 347
 348fail_close:
 349        hv_uio_cleanup(dev, pdata);
 350fail:
 351        kfree(pdata);
 352
 353        return ret;
 354}
 355
 356static int
 357hv_uio_remove(struct hv_device *dev)
 358{
 359        struct hv_uio_private_data *pdata = hv_get_drvdata(dev);
 360
 361        if (!pdata)
 362                return 0;
 363
 364        uio_unregister_device(&pdata->info);
 365        hv_uio_cleanup(dev, pdata);
 366        hv_set_drvdata(dev, NULL);
 367
 368        vmbus_free_ring(dev->channel);
 369        kfree(pdata);
 370        return 0;
 371}
 372
 373static struct hv_driver hv_uio_drv = {
 374        .name = "uio_hv_generic",
 375        .id_table = NULL, /* only dynamic id's */
 376        .probe = hv_uio_probe,
 377        .remove = hv_uio_remove,
 378};
 379
 380static int __init
 381hyperv_module_init(void)
 382{
 383        return vmbus_driver_register(&hv_uio_drv);
 384}
 385
 386static void __exit
 387hyperv_module_exit(void)
 388{
 389        vmbus_driver_unregister(&hv_uio_drv);
 390}
 391
 392module_init(hyperv_module_init);
 393module_exit(hyperv_module_exit);
 394
 395MODULE_VERSION(DRIVER_VERSION);
 396MODULE_LICENSE("GPL v2");
 397MODULE_AUTHOR(DRIVER_AUTHOR);
 398MODULE_DESCRIPTION(DRIVER_DESC);
 399