pc-bios/s390-ccw/virtio.c

   1 /*
   2  * Virtio driver bits
   3  *
   4  * Copyright (c) 2013 Alexander Graf <agraf@suse.de>
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or (at
   7  * your option) any later version. See the COPYING file in the top-level
   8  * directory.
   9  */
  10
  11 #include "libc.h"
  12 #include "s390-ccw.h"
  13 #include "cio.h"
  14 #include "virtio.h"
  15 #include "virtio-scsi.h"
  16 #include "bswap.h"
  17 #include "helper.h"
  18
  19 #define VRING_WAIT_REPLY_TIMEOUT 30
  20
  21 static VRing block[VIRTIO_MAX_VQS];
  22 static char ring_area[VIRTIO_RING_SIZE * VIRTIO_MAX_VQS]
  23                      __attribute__((__aligned__(PAGE_SIZE)));
  24
  25 static VDev vdev = {
  26     .nr_vqs = 1,
  27     .vrings = block,
  28     .cmd_vr_idx = 0,
  29     .ring_area = ring_area,
  30     .wait_reply_timeout = VRING_WAIT_REPLY_TIMEOUT,
  31     .schid = { .one = 1 },
  32     .scsi_block_size = VIRTIO_SCSI_BLOCK_SIZE,
  33     .blk_factor = 1,
  34 };
  35
  36 VDev *virtio_get_device(void)
  37 {
  38     return &vdev;
  39 }
  40
  41 VirtioDevType virtio_get_device_type(void)
  42 {
  43     return vdev.senseid.cu_model;
  44 }
  45
  46 /* virtio spec v1.0 para 4.3.3.2 */
  47 static long kvm_hypercall(unsigned long nr, unsigned long param1,
  48                           unsigned long param2, unsigned long param3)
  49 {
  50     register ulong r_nr asm("1") = nr;
  51     register ulong r_param1 asm("2") = param1;
  52     register ulong r_param2 asm("3") = param2;
  53     register ulong r_param3 asm("4") = param3;
  54     register long retval asm("2");
  55
  56     asm volatile ("diag 2,4,0x500"
  57                   : "=d" (retval)
  58                   : "d" (r_nr), "0" (r_param1), "r"(r_param2), "d"(r_param3)
  59                   : "memory", "cc");
  60
  61     return retval;
  62 }
  63
  64 static long virtio_notify(SubChannelId schid, int vq_idx, long cookie)
  65 {
  66     return kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32 *)&schid,
  67                          vq_idx, cookie);
  68 }
  69
  70 /***********************************************
  71  *             Virtio functions                *
  72  ***********************************************/
  73
  74 int drain_irqs(SubChannelId schid)
  75 {
  76     Irb irb = {};
  77     int r = 0;
  78
  79     while (1) {
  80         /* FIXME: make use of TPI, for that enable subchannel and isc */
  81         if (tsch(schid, &irb)) {
  82             /* Might want to differentiate error codes later on. */
  83             if (irb.scsw.cstat) {
  84                 r = -EIO;
  85             } else if (irb.scsw.dstat != 0xc) {
  86                 r = -EIO;
  87             }
  88             return r;
  89         }
  90     }
  91 }
  92
  93 static int run_ccw(VDev *vdev, int cmd, void *ptr, int len, bool sli)
  94 {
  95     Ccw1 ccw = {};
  96
  97     ccw.cmd_code = cmd;
  98     ccw.cda = (long)ptr;
  99     ccw.count = len;
 100
 101     if (sli) {
 102         ccw.flags |= CCW_FLAG_SLI;
 103     }
 104
 105     return do_cio(vdev->schid, vdev->senseid.cu_type, ptr2u32(&ccw), CCW_FMT1);
 106 }
 107
 108 static void vring_init(VRing *vr, VqInfo *info)
 109 {
 110     void *p = (void *) info->queue;
 111
 112     debug_print_addr("init p", p);
 113     vr->id = info->index;
 114     vr->num = info->num;
 115     vr->desc = p;
 116     vr->avail = p + info->num * sizeof(VRingDesc);
 117     vr->used = (void *)(((unsigned long)&vr->avail->ring[info->num]
 118                + info->align - 1) & ~(info->align - 1));
 119
 120     /* Zero out all relevant field */
 121     vr->avail->flags = 0;
 122     vr->avail->idx = 0;
 123
 124     /* We're running with interrupts off anyways, so don't bother */
 125     vr->used->flags = VRING_USED_F_NO_NOTIFY;
 126     vr->used->idx = 0;
 127     vr->used_idx = 0;
 128     vr->next_idx = 0;
 129     vr->cookie = 0;
 130
 131     debug_print_addr("init vr", vr);
 132 }
 133
 134 bool vring_notify(VRing *vr)
 135 {
 136     vr->cookie = virtio_notify(vr->schid, vr->id, vr->cookie);
 137     return vr->cookie >= 0;
 138 }
 139
 140 void vring_send_buf(VRing *vr, void *p, int len, int flags)
 141 {
 142     /* For follow-up chains we need to keep the first entry point */
 143     if (!(flags & VRING_HIDDEN_IS_CHAIN)) {
 144         vr->avail->ring[vr->avail->idx % vr->num] = vr->next_idx;
 145     }
 146
 147     vr->desc[vr->next_idx].addr = (ulong)p;
 148     vr->desc[vr->next_idx].len = len;
 149     vr->desc[vr->next_idx].flags = flags & ~VRING_HIDDEN_IS_CHAIN;
 150     vr->desc[vr->next_idx].next = vr->next_idx;
 151     vr->desc[vr->next_idx].next++;
 152     vr->next_idx++;
 153
 154     /* Chains only have a single ID */
 155     if (!(flags & VRING_DESC_F_NEXT)) {
 156         vr->avail->idx++;
 157     }
 158 }
 159
 160 u64 get_clock(void)
 161 {
 162     u64 r;
 163
 164     asm volatile("stck %0" : "=Q" (r) : : "cc");
 165     return r;
 166 }
 167
 168 ulong get_second(void)
 169 {
 170     return (get_clock() >> 12) / 1000000;
 171 }
 172
 173 int vr_poll(VRing *vr)
 174 {
 175     if (vr->used->idx == vr->used_idx) {
 176         vring_notify(vr);
 177         yield();
 178         return 0;
 179     }
 180
 181     vr->used_idx = vr->used->idx;
 182     vr->next_idx = 0;
 183     vr->desc[0].len = 0;
 184     vr->desc[0].flags = 0;
 185     return 1; /* vr has been updated */
 186 }
 187
 188 /*
 189  * Wait for the host to reply.
 190  *
 191  * timeout is in seconds if > 0.
 192  *
 193  * Returns 0 on success, 1 on timeout.
 194  */
 195 int vring_wait_reply(void)
 196 {
 197     ulong target_second = get_second() + vdev.wait_reply_timeout;
 198
 199     /* Wait for any queue to be updated by the host */
 200     do {
 201         int i, r = 0;
 202
 203         for (i = 0; i < vdev.nr_vqs; i++) {
 204             r += vr_poll(&vdev.vrings[i]);
 205         }
 206         yield();
 207         if (r) {
 208             return 0;
 209         }
 210     } while (!vdev.wait_reply_timeout || (get_second() < target_second));
 211
 212     return 1;
 213 }
 214
 215 int virtio_run(VDev *vdev, int vqid, VirtioCmd *cmd)
 216 {
 217     VRing *vr = &vdev->vrings[vqid];
 218     int i = 0;
 219
 220     do {
 221         vring_send_buf(vr, cmd[i].data, cmd[i].size,
 222                        cmd[i].flags | (i ? VRING_HIDDEN_IS_CHAIN : 0));
 223     } while (cmd[i++].flags & VRING_DESC_F_NEXT);
 224
 225     vring_wait_reply();
 226     if (drain_irqs(vr->schid)) {
 227         return -1;
 228     }
 229     return 0;
 230 }
 231
 232 void virtio_setup_ccw(VDev *vdev)
 233 {
 234     int i, rc, cfg_size = 0;
 235     unsigned char status = VIRTIO_CONFIG_S_DRIVER_OK;
 236     struct VirtioFeatureDesc {
 237         uint32_t features;
 238         uint8_t index;
 239     } __attribute__((packed)) feats;
 240
 241     IPL_assert(virtio_is_supported(vdev->schid), "PE");
 242     /* device ID has been established now */
 243
 244     vdev->config.blk.blk_size = 0; /* mark "illegal" - setup started... */
 245     vdev->guessed_disk_nature = VIRTIO_GDN_NONE;
 246
 247     run_ccw(vdev, CCW_CMD_VDEV_RESET, NULL, 0, false);
 248
 249     switch (vdev->senseid.cu_model) {
 250     case VIRTIO_ID_NET:
 251         vdev->nr_vqs = 2;
 252         vdev->cmd_vr_idx = 0;
 253         cfg_size = sizeof(vdev->config.net);
 254         break;
 255     case VIRTIO_ID_BLOCK:
 256         vdev->nr_vqs = 1;
 257         vdev->cmd_vr_idx = 0;
 258         cfg_size = sizeof(vdev->config.blk);
 259         break;
 260     case VIRTIO_ID_SCSI:
 261         vdev->nr_vqs = 3;
 262         vdev->cmd_vr_idx = VR_REQUEST;
 263         cfg_size = sizeof(vdev->config.scsi);
 264         break;
 265     default:
 266         panic("Unsupported virtio device\n");
 267     }
 268     IPL_assert(
 269         run_ccw(vdev, CCW_CMD_READ_CONF, &vdev->config, cfg_size, false) == 0,
 270        "Could not get block device configuration");
 271
 272     /* Feature negotiation */
 273     for (i = 0; i < ARRAY_SIZE(vdev->guest_features); i++) {
 274         feats.features = 0;
 275         feats.index = i;
 276         rc = run_ccw(vdev, CCW_CMD_READ_FEAT, &feats, sizeof(feats), false);
 277         IPL_assert(rc == 0, "Could not get features bits");
 278         vdev->guest_features[i] &= bswap32(feats.features);
 279         feats.features = bswap32(vdev->guest_features[i]);
 280         rc = run_ccw(vdev, CCW_CMD_WRITE_FEAT, &feats, sizeof(feats), false);
 281         IPL_assert(rc == 0, "Could not set features bits");
 282     }
 283
 284     for (i = 0; i < vdev->nr_vqs; i++) {
 285         VqInfo info = {
 286             .queue = (unsigned long long) ring_area + (i * VIRTIO_RING_SIZE),
 287             .align = KVM_S390_VIRTIO_RING_ALIGN,
 288             .index = i,
 289             .num = 0,
 290         };
 291         VqConfig config = {
 292             .index = i,
 293             .num = 0,
 294         };
 295
 296         IPL_assert(
 297             run_ccw(vdev, CCW_CMD_READ_VQ_CONF, &config, sizeof(config), false) == 0,
 298             "Could not get block device VQ configuration");
 299         info.num = config.num;
 300         vring_init(&vdev->vrings[i], &info);
 301         vdev->vrings[i].schid = vdev->schid;
 302         IPL_assert(
 303             run_ccw(vdev, CCW_CMD_SET_VQ, &info, sizeof(info), false) == 0,
 304             "Cannot set VQ info");
 305     }
 306     IPL_assert(
 307         run_ccw(vdev, CCW_CMD_WRITE_STATUS, &status, sizeof(status), false) == 0,
 308         "Could not write status to host");
 309 }
 310
 311 bool virtio_is_supported(SubChannelId schid)
 312 {
 313     vdev.schid = schid;
 314     memset(&vdev.senseid, 0, sizeof(vdev.senseid));
 315
 316     /*
 317      * Run sense id command.
 318      * The size of the senseid data differs between devices (notably,
 319      * between virtio devices and dasds), so specify the largest possible
 320      * size and suppress the incorrect length indication for smaller sizes.
 321      */
 322     if (run_ccw(&vdev, CCW_CMD_SENSE_ID, &vdev.senseid, sizeof(vdev.senseid),
 323                 true)) {
 324         return false;
 325     }
 326     if (vdev.senseid.cu_type == 0x3832) {
 327         switch (vdev.senseid.cu_model) {
 328         case VIRTIO_ID_BLOCK:
 329         case VIRTIO_ID_SCSI:
 330         case VIRTIO_ID_NET:
 331             return true;
 332         }
 333     }
 334     return false;
 335 }