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 #include "s390-time.h"
  19
  20 #define VRING_WAIT_REPLY_TIMEOUT 30
  21
  22 static VRing block[VIRTIO_MAX_VQS];
  23 static char ring_area[VIRTIO_RING_SIZE * VIRTIO_MAX_VQS]
  24                      __attribute__((__aligned__(PAGE_SIZE)));
  25
  26 static VDev vdev = {
  27     .nr_vqs = 1,
  28     .vrings = block,
  29     .cmd_vr_idx = 0,
  30     .ring_area = ring_area,
  31     .wait_reply_timeout = VRING_WAIT_REPLY_TIMEOUT,
  32     .schid = { .one = 1 },
  33     .scsi_block_size = VIRTIO_SCSI_BLOCK_SIZE,
  34     .blk_factor = 1,
  35 };
  36
  37 VDev *virtio_get_device(void)
  38 {
  39     return &vdev;
  40 }
  41
  42 VirtioDevType virtio_get_device_type(void)
  43 {
  44     return vdev.senseid.cu_model;
  45 }
  46
  47 /* virtio spec v1.0 para 4.3.3.2 */
  48 static long kvm_hypercall(unsigned long nr, unsigned long param1,
  49                           unsigned long param2, unsigned long param3)
  50 {
  51     register ulong r_nr asm("1") = nr;
  52     register ulong r_param1 asm("2") = param1;
  53     register ulong r_param2 asm("3") = param2;
  54     register ulong r_param3 asm("4") = param3;
  55     register long retval asm("2");
  56
  57     asm volatile ("diag %%r2,%%r4,0x500"
  58                   : "=d" (retval)
  59                   : "d" (r_nr), "0" (r_param1), "r"(r_param2), "d"(r_param3)
  60                   : "memory", "cc");
  61
  62     return retval;
  63 }
  64
  65 static long virtio_notify(SubChannelId schid, int vq_idx, long cookie)
  66 {
  67     return kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32 *)&schid,
  68                          vq_idx, cookie);
  69 }
  70
  71 /***********************************************
  72  *             Virtio functions                *
  73  ***********************************************/
  74
  75 int drain_irqs(SubChannelId schid)
  76 {
  77     Irb irb = {};
  78     int r = 0;
  79
  80     while (1) {
  81         /* FIXME: make use of TPI, for that enable subchannel and isc */
  82         if (tsch(schid, &irb)) {
  83             /* Might want to differentiate error codes later on. */
  84             if (irb.scsw.cstat) {
  85                 r = -EIO;
  86             } else if (irb.scsw.dstat != 0xc) {
  87                 r = -EIO;
  88             }
  89             return r;
  90         }
  91     }
  92 }
  93
  94 static int run_ccw(VDev *vdev, int cmd, void *ptr, int len, bool sli)
  95 {
  96     Ccw1 ccw = {};
  97
  98     ccw.cmd_code = cmd;
  99     ccw.cda = (long)ptr;
 100     ccw.count = len;
 101
 102     if (sli) {
 103         ccw.flags |= CCW_FLAG_SLI;
 104     }
 105
 106     return do_cio(vdev->schid, vdev->senseid.cu_type, ptr2u32(&ccw), CCW_FMT1);
 107 }
 108
 109 static void vring_init(VRing *vr, VqInfo *info)
 110 {
 111     void *p = (void *) info->queue;
 112
 113     debug_print_addr("init p", p);
 114     vr->id = info->index;
 115     vr->num = info->num;
 116     vr->desc = p;
 117     vr->avail = p + info->num * sizeof(VRingDesc);
 118     vr->used = (void *)(((unsigned long)&vr->avail->ring[info->num]
 119                + info->align - 1) & ~(info->align - 1));
 120
 121     /* Zero out all relevant field */
 122     vr->avail->flags = 0;
 123     vr->avail->idx = 0;
 124
 125     /* We're running with interrupts off anyways, so don't bother */
 126     vr->used->flags = VRING_USED_F_NO_NOTIFY;
 127     vr->used->idx = 0;
 128     vr->used_idx = 0;
 129     vr->next_idx = 0;
 130     vr->cookie = 0;
 131
 132     debug_print_addr("init vr", vr);
 133 }
 134
 135 bool vring_notify(VRing *vr)
 136 {
 137     vr->cookie = virtio_notify(vr->schid, vr->id, vr->cookie);
 138     return vr->cookie >= 0;
 139 }
 140
 141 void vring_send_buf(VRing *vr, void *p, int len, int flags)
 142 {
 143     /* For follow-up chains we need to keep the first entry point */
 144     if (!(flags & VRING_HIDDEN_IS_CHAIN)) {
 145         vr->avail->ring[vr->avail->idx % vr->num] = vr->next_idx;
 146     }
 147
 148     vr->desc[vr->next_idx].addr = (ulong)p;
 149     vr->desc[vr->next_idx].len = len;
 150     vr->desc[vr->next_idx].flags = flags & ~VRING_HIDDEN_IS_CHAIN;
 151     vr->desc[vr->next_idx].next = vr->next_idx;
 152     vr->desc[vr->next_idx].next++;
 153     vr->next_idx++;
 154
 155     /* Chains only have a single ID */
 156     if (!(flags & VRING_DESC_F_NEXT)) {
 157         vr->avail->idx++;
 158     }
 159 }
 160
 161 int vr_poll(VRing *vr)
 162 {
 163     if (vr->used->idx == vr->used_idx) {
 164         vring_notify(vr);
 165         yield();
 166         return 0;
 167     }
 168
 169     vr->used_idx = vr->used->idx;
 170     vr->next_idx = 0;
 171     vr->desc[0].len = 0;
 172     vr->desc[0].flags = 0;
 173     return 1; /* vr has been updated */
 174 }
 175
 176 /*
 177  * Wait for the host to reply.
 178  *
 179  * timeout is in seconds if > 0.
 180  *
 181  * Returns 0 on success, 1 on timeout.
 182  */
 183 int vring_wait_reply(void)
 184 {
 185     ulong target_second = get_time_seconds() + vdev.wait_reply_timeout;
 186
 187     /* Wait for any queue to be updated by the host */
 188     do {
 189         int i, r = 0;
 190
 191         for (i = 0; i < vdev.nr_vqs; i++) {
 192             r += vr_poll(&vdev.vrings[i]);
 193         }
 194         yield();
 195         if (r) {
 196             return 0;
 197         }
 198     } while (!vdev.wait_reply_timeout || (get_time_seconds() < target_second));
 199
 200     return 1;
 201 }
 202
 203 int virtio_run(VDev *vdev, int vqid, VirtioCmd *cmd)
 204 {
 205     VRing *vr = &vdev->vrings[vqid];
 206     int i = 0;
 207
 208     do {
 209         vring_send_buf(vr, cmd[i].data, cmd[i].size,
 210                        cmd[i].flags | (i ? VRING_HIDDEN_IS_CHAIN : 0));
 211     } while (cmd[i++].flags & VRING_DESC_F_NEXT);
 212
 213     vring_wait_reply();
 214     if (drain_irqs(vr->schid)) {
 215         return -1;
 216     }
 217     return 0;
 218 }
 219
 220 void virtio_setup_ccw(VDev *vdev)
 221 {
 222     int i, rc, cfg_size = 0;
 223     uint8_t status;
 224     struct VirtioFeatureDesc {
 225         uint32_t features;
 226         uint8_t index;
 227     } __attribute__((packed)) feats;
 228
 229     IPL_assert(virtio_is_supported(vdev->schid), "PE");
 230     /* device ID has been established now */
 231
 232     vdev->config.blk.blk_size = 0; /* mark "illegal" - setup started... */
 233     vdev->guessed_disk_nature = VIRTIO_GDN_NONE;
 234
 235     run_ccw(vdev, CCW_CMD_VDEV_RESET, NULL, 0, false);
 236
 237     status = VIRTIO_CONFIG_S_ACKNOWLEDGE;
 238     rc = run_ccw(vdev, CCW_CMD_WRITE_STATUS, &status, sizeof(status), false);
 239     IPL_assert(rc == 0, "Could not write ACKNOWLEDGE status to host");
 240
 241     switch (vdev->senseid.cu_model) {
 242     case VIRTIO_ID_NET:
 243         vdev->nr_vqs = 2;
 244         vdev->cmd_vr_idx = 0;
 245         cfg_size = sizeof(vdev->config.net);
 246         break;
 247     case VIRTIO_ID_BLOCK:
 248         vdev->nr_vqs = 1;
 249         vdev->cmd_vr_idx = 0;
 250         cfg_size = sizeof(vdev->config.blk);
 251         break;
 252     case VIRTIO_ID_SCSI:
 253         vdev->nr_vqs = 3;
 254         vdev->cmd_vr_idx = VR_REQUEST;
 255         cfg_size = sizeof(vdev->config.scsi);
 256         break;
 257     default:
 258         panic("Unsupported virtio device\n");
 259     }
 260
 261     status |= VIRTIO_CONFIG_S_DRIVER;
 262     rc = run_ccw(vdev, CCW_CMD_WRITE_STATUS, &status, sizeof(status), false);
 263     IPL_assert(rc == 0, "Could not write DRIVER status to host");
 264
 265     /* Feature negotiation */
 266     for (i = 0; i < ARRAY_SIZE(vdev->guest_features); i++) {
 267         feats.features = 0;
 268         feats.index = i;
 269         rc = run_ccw(vdev, CCW_CMD_READ_FEAT, &feats, sizeof(feats), false);
 270         IPL_assert(rc == 0, "Could not get features bits");
 271         vdev->guest_features[i] &= bswap32(feats.features);
 272         feats.features = bswap32(vdev->guest_features[i]);
 273         rc = run_ccw(vdev, CCW_CMD_WRITE_FEAT, &feats, sizeof(feats), false);
 274         IPL_assert(rc == 0, "Could not set features bits");
 275     }
 276
 277     rc = run_ccw(vdev, CCW_CMD_READ_CONF, &vdev->config, cfg_size, false);
 278     IPL_assert(rc == 0, "Could not get virtio device configuration");
 279
 280     for (i = 0; i < vdev->nr_vqs; i++) {
 281         VqInfo info = {
 282             .queue = (unsigned long long) ring_area + (i * VIRTIO_RING_SIZE),
 283             .align = KVM_S390_VIRTIO_RING_ALIGN,
 284             .index = i,
 285             .num = 0,
 286         };
 287         VqConfig config = {
 288             .index = i,
 289             .num = 0,
 290         };
 291
 292         rc = run_ccw(vdev, CCW_CMD_READ_VQ_CONF, &config, sizeof(config), false);
 293         IPL_assert(rc == 0, "Could not get virtio device VQ configuration");
 294         info.num = config.num;
 295         vring_init(&vdev->vrings[i], &info);
 296         vdev->vrings[i].schid = vdev->schid;
 297         IPL_assert(
 298             run_ccw(vdev, CCW_CMD_SET_VQ, &info, sizeof(info), false) == 0,
 299             "Cannot set VQ info");
 300     }
 301
 302     status |= VIRTIO_CONFIG_S_DRIVER_OK;
 303     rc = run_ccw(vdev, CCW_CMD_WRITE_STATUS, &status, sizeof(status), false);
 304     IPL_assert(rc == 0, "Could not write DRIVER_OK status to host");
 305 }
 306
 307 bool virtio_is_supported(SubChannelId schid)
 308 {
 309     vdev.schid = schid;
 310     memset(&vdev.senseid, 0, sizeof(vdev.senseid));
 311
 312     /*
 313      * Run sense id command.
 314      * The size of the senseid data differs between devices (notably,
 315      * between virtio devices and dasds), so specify the largest possible
 316      * size and suppress the incorrect length indication for smaller sizes.
 317      */
 318     if (run_ccw(&vdev, CCW_CMD_SENSE_ID, &vdev.senseid, sizeof(vdev.senseid),
 319                 true)) {
 320         return false;
 321     }
 322     if (vdev.senseid.cu_type == 0x3832) {
 323         switch (vdev.senseid.cu_model) {
 324         case VIRTIO_ID_BLOCK:
 325         case VIRTIO_ID_SCSI:
 326         case VIRTIO_ID_NET:
 327             return true;
 328         }
 329     }
 330     return false;
 331 }