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 "virtio.h"
  14 #include "virtio-scsi.h"
  15 #include "bswap.h"
  16
  17 #define VRING_WAIT_REPLY_TIMEOUT 30
  18
  19 static VRing block[VIRTIO_MAX_VQS];
  20 static char ring_area[VIRTIO_RING_SIZE * VIRTIO_MAX_VQS]
  21                      __attribute__((__aligned__(PAGE_SIZE)));
  22
  23 static char chsc_page[PAGE_SIZE] __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)
  94 {
  95     Ccw1 ccw = {};
  96     CmdOrb orb = {};
  97     Schib schib;
  98     int r;
  99
 100     /* start command processing */
 101     stsch_err(vdev->schid, &schib);
 102     /* enable the subchannel for IPL device */
 103     schib.pmcw.ena = 1;
 104     msch(vdev->schid, &schib);
 105
 106     /* start subchannel command */
 107     orb.fmt = 1;
 108     orb.cpa = (u32)(long)&ccw;
 109     orb.lpm = 0x80;
 110
 111     ccw.cmd_code = cmd;
 112     ccw.cda = (long)ptr;
 113     ccw.count = len;
 114
 115     r = ssch(vdev->schid, &orb);
 116     /*
 117      * XXX Wait until device is done processing the CCW. For now we can
 118      *     assume that a simple tsch will have finished the CCW processing,
 119      *     but the architecture allows for asynchronous operation
 120      */
 121     if (!r) {
 122         r = drain_irqs(vdev->schid);
 123     }
 124     return r;
 125 }
 126
 127 static void vring_init(VRing *vr, VqInfo *info)
 128 {
 129     void *p = (void *) info->queue;
 130
 131     debug_print_addr("init p", p);
 132     vr->id = info->index;
 133     vr->num = info->num;
 134     vr->desc = p;
 135     vr->avail = p + info->num * sizeof(VRingDesc);
 136     vr->used = (void *)(((unsigned long)&vr->avail->ring[info->num]
 137                + info->align - 1) & ~(info->align - 1));
 138
 139     /* Zero out all relevant field */
 140     vr->avail->flags = 0;
 141     vr->avail->idx = 0;
 142
 143     /* We're running with interrupts off anyways, so don't bother */
 144     vr->used->flags = VRING_USED_F_NO_NOTIFY;
 145     vr->used->idx = 0;
 146     vr->used_idx = 0;
 147     vr->next_idx = 0;
 148     vr->cookie = 0;
 149
 150     debug_print_addr("init vr", vr);
 151 }
 152
 153 bool vring_notify(VRing *vr)
 154 {
 155     vr->cookie = virtio_notify(vr->schid, vr->id, vr->cookie);
 156     return vr->cookie >= 0;
 157 }
 158
 159 void vring_send_buf(VRing *vr, void *p, int len, int flags)
 160 {
 161     /* For follow-up chains we need to keep the first entry point */
 162     if (!(flags & VRING_HIDDEN_IS_CHAIN)) {
 163         vr->avail->ring[vr->avail->idx % vr->num] = vr->next_idx;
 164     }
 165
 166     vr->desc[vr->next_idx].addr = (ulong)p;
 167     vr->desc[vr->next_idx].len = len;
 168     vr->desc[vr->next_idx].flags = flags & ~VRING_HIDDEN_IS_CHAIN;
 169     vr->desc[vr->next_idx].next = vr->next_idx;
 170     vr->desc[vr->next_idx].next++;
 171     vr->next_idx++;
 172
 173     /* Chains only have a single ID */
 174     if (!(flags & VRING_DESC_F_NEXT)) {
 175         vr->avail->idx++;
 176     }
 177 }
 178
 179 u64 get_clock(void)
 180 {
 181     u64 r;
 182
 183     asm volatile("stck %0" : "=Q" (r) : : "cc");
 184     return r;
 185 }
 186
 187 ulong get_second(void)
 188 {
 189     return (get_clock() >> 12) / 1000000;
 190 }
 191
 192 int vr_poll(VRing *vr)
 193 {
 194     if (vr->used->idx == vr->used_idx) {
 195         vring_notify(vr);
 196         yield();
 197         return 0;
 198     }
 199
 200     vr->used_idx = vr->used->idx;
 201     vr->next_idx = 0;
 202     vr->desc[0].len = 0;
 203     vr->desc[0].flags = 0;
 204     return 1; /* vr has been updated */
 205 }
 206
 207 /*
 208  * Wait for the host to reply.
 209  *
 210  * timeout is in seconds if > 0.
 211  *
 212  * Returns 0 on success, 1 on timeout.
 213  */
 214 int vring_wait_reply(void)
 215 {
 216     ulong target_second = get_second() + vdev.wait_reply_timeout;
 217
 218     /* Wait for any queue to be updated by the host */
 219     do {
 220         int i, r = 0;
 221
 222         for (i = 0; i < vdev.nr_vqs; i++) {
 223             r += vr_poll(&vdev.vrings[i]);
 224         }
 225         yield();
 226         if (r) {
 227             return 0;
 228         }
 229     } while (!vdev.wait_reply_timeout || (get_second() < target_second));
 230
 231     return 1;
 232 }
 233
 234 int virtio_run(VDev *vdev, int vqid, VirtioCmd *cmd)
 235 {
 236     VRing *vr = &vdev->vrings[vqid];
 237     int i = 0;
 238
 239     do {
 240         vring_send_buf(vr, cmd[i].data, cmd[i].size,
 241                        cmd[i].flags | (i ? VRING_HIDDEN_IS_CHAIN : 0));
 242     } while (cmd[i++].flags & VRING_DESC_F_NEXT);
 243
 244     vring_wait_reply();
 245     if (drain_irqs(vr->schid)) {
 246         return -1;
 247     }
 248     return 0;
 249 }
 250
 251 void virtio_setup_ccw(VDev *vdev)
 252 {
 253     int i, rc, cfg_size = 0;
 254     unsigned char status = VIRTIO_CONFIG_S_DRIVER_OK;
 255     struct VirtioFeatureDesc {
 256         uint32_t features;
 257         uint8_t index;
 258     } __attribute__((packed)) feats;
 259
 260     IPL_assert(virtio_is_supported(vdev->schid), "PE");
 261     /* device ID has been established now */
 262
 263     vdev->config.blk.blk_size = 0; /* mark "illegal" - setup started... */
 264     vdev->guessed_disk_nature = VIRTIO_GDN_NONE;
 265
 266     run_ccw(vdev, CCW_CMD_VDEV_RESET, NULL, 0);
 267
 268     switch (vdev->senseid.cu_model) {
 269     case VIRTIO_ID_NET:
 270         vdev->nr_vqs = 2;
 271         vdev->cmd_vr_idx = 0;
 272         cfg_size = sizeof(vdev->config.net);
 273         break;
 274     case VIRTIO_ID_BLOCK:
 275         vdev->nr_vqs = 1;
 276         vdev->cmd_vr_idx = 0;
 277         cfg_size = sizeof(vdev->config.blk);
 278         break;
 279     case VIRTIO_ID_SCSI:
 280         vdev->nr_vqs = 3;
 281         vdev->cmd_vr_idx = VR_REQUEST;
 282         cfg_size = sizeof(vdev->config.scsi);
 283         break;
 284     default:
 285         panic("Unsupported virtio device\n");
 286     }
 287     IPL_assert(run_ccw(vdev, CCW_CMD_READ_CONF, &vdev->config, cfg_size) == 0,
 288                "Could not get block device configuration");
 289
 290     /* Feature negotiation */
 291     for (i = 0; i < ARRAY_SIZE(vdev->guest_features); i++) {
 292         feats.features = 0;
 293         feats.index = i;
 294         rc = run_ccw(vdev, CCW_CMD_READ_FEAT, &feats, sizeof(feats));
 295         IPL_assert(rc == 0, "Could not get features bits");
 296         vdev->guest_features[i] &= bswap32(feats.features);
 297         feats.features = bswap32(vdev->guest_features[i]);
 298         rc = run_ccw(vdev, CCW_CMD_WRITE_FEAT, &feats, sizeof(feats));
 299         IPL_assert(rc == 0, "Could not set features bits");
 300     }
 301
 302     for (i = 0; i < vdev->nr_vqs; i++) {
 303         VqInfo info = {
 304             .queue = (unsigned long long) ring_area + (i * VIRTIO_RING_SIZE),
 305             .align = KVM_S390_VIRTIO_RING_ALIGN,
 306             .index = i,
 307             .num = 0,
 308         };
 309         VqConfig config = {
 310             .index = i,
 311             .num = 0,
 312         };
 313
 314         IPL_assert(
 315             run_ccw(vdev, CCW_CMD_READ_VQ_CONF, &config, sizeof(config)) == 0,
 316             "Could not get block device VQ configuration");
 317         info.num = config.num;
 318         vring_init(&vdev->vrings[i], &info);
 319         vdev->vrings[i].schid = vdev->schid;
 320         IPL_assert(run_ccw(vdev, CCW_CMD_SET_VQ, &info, sizeof(info)) == 0,
 321                    "Cannot set VQ info");
 322     }
 323     IPL_assert(
 324         run_ccw(vdev, CCW_CMD_WRITE_STATUS, &status, sizeof(status)) == 0,
 325         "Could not write status to host");
 326 }
 327
 328 bool virtio_is_supported(SubChannelId schid)
 329 {
 330     vdev.schid = schid;
 331     memset(&vdev.senseid, 0, sizeof(vdev.senseid));
 332     /* run sense id command */
 333     if (run_ccw(&vdev, CCW_CMD_SENSE_ID, &vdev.senseid, sizeof(vdev.senseid))) {
 334         return false;
 335     }
 336     if (vdev.senseid.cu_type == 0x3832) {
 337         switch (vdev.senseid.cu_model) {
 338         case VIRTIO_ID_BLOCK:
 339         case VIRTIO_ID_SCSI:
 340         case VIRTIO_ID_NET:
 341             return true;
 342         }
 343     }
 344     return false;
 345 }
 346
 347 int enable_mss_facility(void)
 348 {
 349     int ret;
 350     ChscAreaSda *sda_area = (ChscAreaSda *) chsc_page;
 351
 352     memset(sda_area, 0, PAGE_SIZE);
 353     sda_area->request.length = 0x0400;
 354     sda_area->request.code = 0x0031;
 355     sda_area->operation_code = 0x2;
 356
 357     ret = chsc(sda_area);
 358     if ((ret == 0) && (sda_area->response.code == 0x0001)) {
 359         return 0;
 360     }
 361     return -EIO;
 362 }