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 "s390-ccw.h"
  12 #include "virtio.h"
  13
  14 struct vring block;
  15
  16 static char chsc_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
  17
  18 static long kvm_hypercall(unsigned long nr, unsigned long param1,
  19                           unsigned long param2)
  20 {
  21         register ulong r_nr asm("1") = nr;
  22         register ulong r_param1 asm("2") = param1;
  23         register ulong r_param2 asm("3") = param2;
  24         register long retval asm("2");
  25
  26         asm volatile ("diag 2,4,0x500"
  27                       : "=d" (retval)
  28                       : "d" (r_nr), "0" (r_param1), "r"(r_param2)
  29                       : "memory", "cc");
  30
  31         return retval;
  32 }
  33
  34 static void virtio_notify(struct subchannel_id schid)
  35 {
  36     kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32*)&schid, 0);
  37 }
  38
  39 /***********************************************
  40  *             Virtio functions                *
  41  ***********************************************/
  42
  43 static int drain_irqs(struct subchannel_id schid)
  44 {
  45     struct irb irb = {};
  46     int r = 0;
  47
  48     while (1) {
  49         /* FIXME: make use of TPI, for that enable subchannel and isc */
  50         if (tsch(schid, &irb)) {
  51             /* Might want to differentiate error codes later on. */
  52             if (irb.scsw.cstat) {
  53                 r = -EIO;
  54             } else if (irb.scsw.dstat != 0xc) {
  55                 r = -EIO;
  56             }
  57             return r;
  58         }
  59     }
  60 }
  61
  62 static int run_ccw(struct subchannel_id schid, int cmd, void *ptr, int len)
  63 {
  64     struct ccw1 ccw = {};
  65     struct cmd_orb orb = {};
  66     struct schib schib;
  67     int r;
  68
  69     /* start command processing */
  70     stsch_err(schid, &schib);
  71     schib.scsw.ctrl = SCSW_FCTL_START_FUNC;
  72     msch(schid, &schib);
  73
  74     /* start subchannel command */
  75     orb.fmt = 1;
  76     orb.cpa = (u32)(long)&ccw;
  77     orb.lpm = 0x80;
  78
  79     ccw.cmd_code = cmd;
  80     ccw.cda = (long)ptr;
  81     ccw.count = len;
  82
  83     r = ssch(schid, &orb);
  84     /*
  85      * XXX Wait until device is done processing the CCW. For now we can
  86      *     assume that a simple tsch will have finished the CCW processing,
  87      *     but the architecture allows for asynchronous operation
  88      */
  89     if (!r) {
  90         r = drain_irqs(schid);
  91     }
  92     return r;
  93 }
  94
  95 static void virtio_set_status(struct subchannel_id schid,
  96                               unsigned long dev_addr)
  97 {
  98     unsigned char status = dev_addr;
  99     if (run_ccw(schid, CCW_CMD_WRITE_STATUS, &status, sizeof(status))) {
 100         virtio_panic("Could not write status to host!\n");
 101     }
 102 }
 103
 104 static void virtio_reset(struct subchannel_id schid)
 105 {
 106     run_ccw(schid, CCW_CMD_VDEV_RESET, NULL, 0);
 107 }
 108
 109 static void vring_init(struct vring *vr, unsigned int num, void *p,
 110                        unsigned long align)
 111 {
 112     debug_print_addr("init p", p);
 113     vr->num = num;
 114     vr->desc = p;
 115     vr->avail = p + num*sizeof(struct vring_desc);
 116     vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + align-1)
 117                 & ~(align - 1));
 118
 119     /* Zero out all relevant field */
 120     vr->avail->flags = 0;
 121     vr->avail->idx = 0;
 122
 123     /* We're running with interrupts off anyways, so don't bother */
 124     vr->used->flags = VRING_USED_F_NO_NOTIFY;
 125     vr->used->idx = 0;
 126     vr->used_idx = 0;
 127
 128     debug_print_addr("init vr", vr);
 129 }
 130
 131 static void vring_notify(struct subchannel_id schid)
 132 {
 133     virtio_notify(schid);
 134 }
 135
 136 static void vring_send_buf(struct vring *vr, void *p, int len, int flags)
 137 {
 138     /* For follow-up chains we need to keep the first entry point */
 139     if (!(flags & VRING_HIDDEN_IS_CHAIN)) {
 140         vr->avail->ring[vr->avail->idx % vr->num] = vr->next_idx;
 141     }
 142
 143     vr->desc[vr->next_idx].addr = (ulong)p;
 144     vr->desc[vr->next_idx].len = len;
 145     vr->desc[vr->next_idx].flags = flags & ~VRING_HIDDEN_IS_CHAIN;
 146     vr->desc[vr->next_idx].next = vr->next_idx;
 147     vr->desc[vr->next_idx].next++;
 148     vr->next_idx++;
 149
 150     /* Chains only have a single ID */
 151     if (!(flags & VRING_DESC_F_NEXT)) {
 152         vr->avail->idx++;
 153     }
 154 }
 155
 156 static u64 get_clock(void)
 157 {
 158     u64 r;
 159
 160     asm volatile("stck %0" : "=Q" (r) : : "cc");
 161     return r;
 162 }
 163
 164 static ulong get_second(void)
 165 {
 166     return (get_clock() >> 12) / 1000000;
 167 }
 168
 169 /*
 170  * Wait for the host to reply.
 171  *
 172  * timeout is in seconds if > 0.
 173  *
 174  * Returns 0 on success, 1 on timeout.
 175  */
 176 static int vring_wait_reply(struct vring *vr, int timeout)
 177 {
 178     ulong target_second = get_second() + timeout;
 179     struct subchannel_id schid = vr->schid;
 180     int r = 0;
 181
 182     /* Wait until the used index has moved. */
 183     while (vr->used->idx == vr->used_idx) {
 184         vring_notify(schid);
 185         if (timeout && (get_second() >= target_second)) {
 186             r = 1;
 187             break;
 188         }
 189         yield();
 190     }
 191
 192     vr->used_idx = vr->used->idx;
 193     vr->next_idx = 0;
 194     vr->desc[0].len = 0;
 195     vr->desc[0].flags = 0;
 196
 197     return r;
 198 }
 199
 200 /***********************************************
 201  *               Virtio block                  *
 202  ***********************************************/
 203
 204 static int virtio_read_many(ulong sector, void *load_addr, int sec_num)
 205 {
 206     struct virtio_blk_outhdr out_hdr;
 207     u8 status;
 208     int r;
 209
 210     /* Tell the host we want to read */
 211     out_hdr.type = VIRTIO_BLK_T_IN;
 212     out_hdr.ioprio = 99;
 213     out_hdr.sector = sector;
 214
 215     vring_send_buf(&block, &out_hdr, sizeof(out_hdr), VRING_DESC_F_NEXT);
 216
 217     /* This is where we want to receive data */
 218     vring_send_buf(&block, load_addr, SECTOR_SIZE * sec_num,
 219                    VRING_DESC_F_WRITE | VRING_HIDDEN_IS_CHAIN |
 220                    VRING_DESC_F_NEXT);
 221
 222     /* status field */
 223     vring_send_buf(&block, &status, sizeof(u8), VRING_DESC_F_WRITE |
 224                    VRING_HIDDEN_IS_CHAIN);
 225
 226     /* Now we can tell the host to read */
 227     vring_wait_reply(&block, 0);
 228
 229     r = drain_irqs(block.schid);
 230     if (r) {
 231         /* Well, whatever status is supposed to contain... */
 232         status = 1;
 233     }
 234     return status;
 235 }
 236
 237 unsigned long virtio_load_direct(ulong rec_list1, ulong rec_list2,
 238                                  ulong subchan_id, void *load_addr)
 239 {
 240     u8 status;
 241     int sec = rec_list1;
 242     int sec_num = (((rec_list2 >> 32)+ 1) & 0xffff);
 243     int sec_len = rec_list2 >> 48;
 244     ulong addr = (ulong)load_addr;
 245
 246     if (sec_len != SECTOR_SIZE) {
 247         return -1;
 248     }
 249
 250     sclp_print(".");
 251     status = virtio_read_many(sec, (void*)addr, sec_num);
 252     if (status) {
 253         virtio_panic("I/O Error");
 254     }
 255     addr += sec_num * SECTOR_SIZE;
 256
 257     return addr;
 258 }
 259
 260 int virtio_read(ulong sector, void *load_addr)
 261 {
 262     return virtio_read_many(sector, load_addr, 1);
 263 }
 264
 265 void virtio_setup_block(struct subchannel_id schid)
 266 {
 267     struct vq_info_block info;
 268     struct vq_config_block config = {};
 269
 270     virtio_reset(schid);
 271
 272     config.index = 0;
 273     if (run_ccw(schid, CCW_CMD_READ_VQ_CONF, &config, sizeof(config))) {
 274         virtio_panic("Could not get block device configuration\n");
 275     }
 276     vring_init(&block, config.num, (void*)(100 * 1024 * 1024),
 277                KVM_S390_VIRTIO_RING_ALIGN);
 278
 279     info.queue = (100ULL * 1024ULL* 1024ULL);
 280     info.align = KVM_S390_VIRTIO_RING_ALIGN;
 281     info.index = 0;
 282     info.num = config.num;
 283     block.schid = schid;
 284
 285     if (!run_ccw(schid, CCW_CMD_SET_VQ, &info, sizeof(info))) {
 286         virtio_set_status(schid, VIRTIO_CONFIG_S_DRIVER_OK);
 287     }
 288 }
 289
 290 bool virtio_is_blk(struct subchannel_id schid)
 291 {
 292     int r;
 293     struct senseid senseid = {};
 294
 295     /* run sense id command */
 296     r = run_ccw(schid, CCW_CMD_SENSE_ID, &senseid, sizeof(senseid));
 297     if (r) {
 298         return false;
 299     }
 300     if ((senseid.cu_type != 0x3832) || (senseid.cu_model != VIRTIO_ID_BLOCK)) {
 301         return false;
 302     }
 303
 304     return true;
 305 }
 306
 307 int enable_mss_facility(void)
 308 {
 309     int ret;
 310     struct chsc_area_sda *sda_area = (struct chsc_area_sda *) chsc_page;
 311
 312     memset(sda_area, 0, PAGE_SIZE);
 313     sda_area->request.length = 0x0400;
 314     sda_area->request.code = 0x0031;
 315     sda_area->operation_code = 0x2;
 316
 317     ret = chsc(sda_area);
 318     if ((ret == 0) && (sda_area->response.code == 0x0001)) {
 319         return 0;
 320     }
 321     return -EIO;
 322 }