drivers/vdpa/vdpa_sim/vdpa_sim_net.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * VDPA simulator for networking device.
   4  *
   5  * Copyright (c) 2020, Red Hat Inc. All rights reserved.
   6  *     Author: Jason Wang <jasowang@redhat.com>
   7  *
   8  */
   9
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/device.h>
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/etherdevice.h>
  16 #include <linux/vringh.h>
  17 #include <linux/vdpa.h>
  18 #include <uapi/linux/virtio_net.h>
  19
  20 #include "vdpa_sim.h"
  21
  22 #define DRV_VERSION  "0.1"
  23 #define DRV_AUTHOR   "Jason Wang <jasowang@redhat.com>"
  24 #define DRV_DESC     "vDPA Device Simulator for networking device"
  25 #define DRV_LICENSE  "GPL v2"
  26
  27 #define VDPASIM_NET_FEATURES    (VDPASIM_FEATURES | \
  28                                  (1ULL << VIRTIO_NET_F_MAC))
  29
  30 #define VDPASIM_NET_VQ_NUM      2
  31
  32 static char *macaddr;
  33 module_param(macaddr, charp, 0);
  34 MODULE_PARM_DESC(macaddr, "Ethernet MAC address");
  35
  36 u8 macaddr_buf[ETH_ALEN];
  37
  38 static struct vdpasim *vdpasim_net_dev;
  39
  40 static void vdpasim_net_work(struct work_struct *work)
  41 {
  42         struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
  43         struct vdpasim_virtqueue *txq = &vdpasim->vqs[1];
  44         struct vdpasim_virtqueue *rxq = &vdpasim->vqs[0];
  45         ssize_t read, write;
  46         size_t total_write;
  47         int pkts = 0;
  48         int err;
  49
  50         spin_lock(&vdpasim->lock);
  51
  52         if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK))
  53                 goto out;
  54
  55         if (!txq->ready || !rxq->ready)
  56                 goto out;
  57
  58         while (true) {
  59                 total_write = 0;
  60                 err = vringh_getdesc_iotlb(&txq->vring, &txq->out_iov, NULL,
  61                                            &txq->head, GFP_ATOMIC);
  62                 if (err <= 0)
  63                         break;
  64
  65                 err = vringh_getdesc_iotlb(&rxq->vring, NULL, &rxq->in_iov,
  66                                            &rxq->head, GFP_ATOMIC);
  67                 if (err <= 0) {
  68                         vringh_complete_iotlb(&txq->vring, txq->head, 0);
  69                         break;
  70                 }
  71
  72                 while (true) {
  73                         read = vringh_iov_pull_iotlb(&txq->vring, &txq->out_iov,
  74                                                      vdpasim->buffer,
  75                                                      PAGE_SIZE);
  76                         if (read <= 0)
  77                                 break;
  78
  79                         write = vringh_iov_push_iotlb(&rxq->vring, &rxq->in_iov,
  80                                                       vdpasim->buffer, read);
  81                         if (write <= 0)
  82                                 break;
  83
  84                         total_write += write;
  85                 }
  86
  87                 /* Make sure data is wrote before advancing index */
  88                 smp_wmb();
  89
  90                 vringh_complete_iotlb(&txq->vring, txq->head, 0);
  91                 vringh_complete_iotlb(&rxq->vring, rxq->head, total_write);
  92
  93                 /* Make sure used is visible before rasing the interrupt. */
  94                 smp_wmb();
  95
  96                 local_bh_disable();
  97                 if (vringh_need_notify_iotlb(&txq->vring) > 0)
  98                         vringh_notify(&txq->vring);
  99                 if (vringh_need_notify_iotlb(&rxq->vring) > 0)
 100                         vringh_notify(&rxq->vring);
 101                 local_bh_enable();
 102
 103                 if (++pkts > 4) {
 104                         schedule_work(&vdpasim->work);
 105                         goto out;
 106                 }
 107         }
 108
 109 out:
 110         spin_unlock(&vdpasim->lock);
 111 }
 112
 113 static void vdpasim_net_get_config(struct vdpasim *vdpasim, void *config)
 114 {
 115         struct virtio_net_config *net_config =
 116                 (struct virtio_net_config *)config;
 117
 118         net_config->mtu = cpu_to_vdpasim16(vdpasim, 1500);
 119         net_config->status = cpu_to_vdpasim16(vdpasim, VIRTIO_NET_S_LINK_UP);
 120         memcpy(net_config->mac, macaddr_buf, ETH_ALEN);
 121 }
 122
 123 static int __init vdpasim_net_init(void)
 124 {
 125         struct vdpasim_dev_attr dev_attr = {};
 126         int ret;
 127
 128         if (macaddr) {
 129                 mac_pton(macaddr, macaddr_buf);
 130                 if (!is_valid_ether_addr(macaddr_buf)) {
 131                         ret = -EADDRNOTAVAIL;
 132                         goto out;
 133                 }
 134         } else {
 135                 eth_random_addr(macaddr_buf);
 136         }
 137
 138         dev_attr.id = VIRTIO_ID_NET;
 139         dev_attr.supported_features = VDPASIM_NET_FEATURES;
 140         dev_attr.nvqs = VDPASIM_NET_VQ_NUM;
 141         dev_attr.config_size = sizeof(struct virtio_net_config);
 142         dev_attr.get_config = vdpasim_net_get_config;
 143         dev_attr.work_fn = vdpasim_net_work;
 144         dev_attr.buffer_size = PAGE_SIZE;
 145
 146         vdpasim_net_dev = vdpasim_create(&dev_attr);
 147         if (IS_ERR(vdpasim_net_dev)) {
 148                 ret = PTR_ERR(vdpasim_net_dev);
 149                 goto out;
 150         }
 151
 152         ret = vdpa_register_device(&vdpasim_net_dev->vdpa);
 153         if (ret)
 154                 goto put_dev;
 155
 156         return 0;
 157
 158 put_dev:
 159         put_device(&vdpasim_net_dev->vdpa.dev);
 160 out:
 161         return ret;
 162 }
 163
 164 static void __exit vdpasim_net_exit(void)
 165 {
 166         struct vdpa_device *vdpa = &vdpasim_net_dev->vdpa;
 167
 168         vdpa_unregister_device(vdpa);
 169 }
 170
 171 module_init(vdpasim_net_init);
 172 module_exit(vdpasim_net_exit);
 173
 174 MODULE_VERSION(DRV_VERSION);
 175 MODULE_LICENSE(DRV_LICENSE);
 176 MODULE_AUTHOR(DRV_AUTHOR);
 177 MODULE_DESCRIPTION(DRV_DESC);