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