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 unsigned long r_nr asm("1") = nr; 52 register unsigned long r_param1 asm("2") = param1; 53 register unsigned long r_param2 asm("3") = param2; 54 register unsigned long 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 = (unsigned long)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 unsigned long 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 } 332