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 3 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 static 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 } 363