| 1 | /* |
| 2 | * Virtio functionality for CCW devices |
| 3 | * |
| 4 | * SPDX-License-Identifier: GPL-2.0-or-later |
| 5 | * |
| 6 | * Copyright (c) 2013 Alexander Graf <agraf@suse.de> |
| 7 | * Copyright 2025 IBM Corp. |
| 8 | * |
| 9 | * Author(s): Jared Rossi <jrossi@linux.ibm.com> |
| 10 | */ |
| 11 | |
| 12 | #include <string.h> |
| 13 | #include "s390-ccw.h" |
| 14 | #include "cio.h" |
| 15 | #include "virtio.h" |
| 16 | #include "virtio-ccw.h" |
| 17 | #include "virtio-scsi.h" |
| 18 | #include "bswap.h" |
| 19 | #include "helper.h" |
| 20 | #include "s390-time.h" |
| 21 | |
| 22 | /* virtio spec v1.0 para 4.3.3.2 */ |
| 23 | static long kvm_hypercall(unsigned long nr, unsigned long param1, |
| 24 | unsigned long param2, unsigned long param3) |
| 25 | { |
| 26 | register unsigned long r_nr asm("1") = nr; |
| 27 | register unsigned long r_param1 asm("2") = param1; |
| 28 | register unsigned long r_param2 asm("3") = param2; |
| 29 | register unsigned long r_param3 asm("4") = param3; |
| 30 | register long retval asm("2"); |
| 31 | |
| 32 | asm volatile ("diag %%r2,%%r4,0x500" |
| 33 | : "=d" (retval) |
| 34 | : "d" (r_nr), "0" (r_param1), "r"(r_param2), "d"(r_param3) |
| 35 | : "memory", "cc"); |
| 36 | |
| 37 | return retval; |
| 38 | } |
| 39 | |
| 40 | static int run_ccw(VDev *vdev, int cmd, void *ptr, int len, bool sli) |
| 41 | { |
| 42 | Ccw1 ccw = {}; |
| 43 | |
| 44 | ccw.cmd_code = cmd; |
| 45 | ccw.cda = (long)ptr; |
| 46 | ccw.count = len; |
| 47 | |
| 48 | if (sli) { |
| 49 | ccw.flags |= CCW_FLAG_SLI; |
| 50 | } |
| 51 | |
| 52 | return do_cio(vdev->schid, vdev->senseid.cu_type, ptr2u32(&ccw), CCW_FMT1); |
| 53 | } |
| 54 | |
| 55 | bool virtio_ccw_is_supported(VDev *vdev) |
| 56 | { |
| 57 | memset(&vdev->senseid, 0, sizeof(vdev->senseid)); |
| 58 | |
| 59 | /* |
| 60 | * Run sense id command. |
| 61 | * The size of the senseid data differs between devices (notably, |
| 62 | * between virtio devices and dasds), so specify the largest possible |
| 63 | * size and suppress the incorrect length indication for smaller sizes. |
| 64 | */ |
| 65 | if (run_ccw(vdev, CCW_CMD_SENSE_ID, &vdev->senseid, sizeof(vdev->senseid), |
| 66 | true)) { |
| 67 | return false; |
| 68 | } |
| 69 | |
| 70 | vdev->dev_type = vdev->senseid.cu_model; |
| 71 | |
| 72 | if (vdev->senseid.cu_type == 0x3832) { |
| 73 | switch (vdev->dev_type) { |
| 74 | case VIRTIO_ID_BLOCK: |
| 75 | case VIRTIO_ID_SCSI: |
| 76 | case VIRTIO_ID_NET: |
| 77 | return true; |
| 78 | default: |
| 79 | return false; |
| 80 | } |
| 81 | } |
| 82 | return false; |
| 83 | } |
| 84 | |
| 85 | int drain_irqs_ccw(SubChannelId schid) |
| 86 | { |
| 87 | Irb irb = {}; |
| 88 | int r = 0; |
| 89 | |
| 90 | while (1) { |
| 91 | /* FIXME: make use of TPI, for that enable subchannel and isc */ |
| 92 | if (tsch(schid, &irb)) { |
| 93 | /* Might want to differentiate error codes later on. */ |
| 94 | if (irb.scsw.cstat) { |
| 95 | r = -EIO; |
| 96 | } else if (irb.scsw.dstat != 0xc) { |
| 97 | r = -EIO; |
| 98 | } |
| 99 | return r; |
| 100 | } |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | long virtio_ccw_notify(SubChannelId schid, int vq_idx, long cookie) |
| 105 | { |
| 106 | return kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32 *)&schid, |
| 107 | vq_idx, cookie); |
| 108 | } |
| 109 | |
| 110 | int virtio_ccw_run(VDev *vdev, int vqid, VirtioCmd *cmd) |
| 111 | { |
| 112 | VRing *vr = &vdev->vrings[vqid]; |
| 113 | int i = 0; |
| 114 | |
| 115 | do { |
| 116 | vring_send_buf(vr, cmd[i].data, cmd[i].size, |
| 117 | cmd[i].flags | (i ? VRING_HIDDEN_IS_CHAIN : 0)); |
| 118 | } while (cmd[i++].flags & VRING_DESC_F_NEXT); |
| 119 | |
| 120 | vring_wait_reply(); |
| 121 | if (drain_irqs()) { |
| 122 | return -1; |
| 123 | } |
| 124 | return 0; |
| 125 | } |
| 126 | |
| 127 | int virtio_ccw_reset(VDev *vdev) |
| 128 | { |
| 129 | return run_ccw(vdev, CCW_CMD_VDEV_RESET, NULL, 0, false); |
| 130 | } |
| 131 | |
| 132 | int virtio_ccw_setup(VDev *vdev) |
| 133 | { |
| 134 | int i, cfg_size = 0; |
| 135 | uint8_t status; |
| 136 | struct VirtioFeatureDesc { |
| 137 | uint32_t features; |
| 138 | uint8_t index; |
| 139 | } __attribute__((packed)) feats; |
| 140 | |
| 141 | if (!virtio_ccw_is_supported(vdev)) { |
| 142 | puts("Virtio unsupported for this device ID"); |
| 143 | return -ENODEV; |
| 144 | } |
| 145 | /* device ID has been established now */ |
| 146 | |
| 147 | vdev->config.blk.blk_size = 0; /* mark "illegal" - setup started... */ |
| 148 | vdev->guessed_disk_nature = VIRTIO_GDN_NONE; |
| 149 | |
| 150 | virtio_reset(vdev); |
| 151 | |
| 152 | status = VIRTIO_CONFIG_S_ACKNOWLEDGE; |
| 153 | if (run_ccw(vdev, CCW_CMD_WRITE_STATUS, &status, sizeof(status), false)) { |
| 154 | puts("Could not write ACKNOWLEDGE status to host"); |
| 155 | return -EIO; |
| 156 | } |
| 157 | |
| 158 | switch (vdev->dev_type) { |
| 159 | case VIRTIO_ID_NET: |
| 160 | vdev->nr_vqs = 2; |
| 161 | vdev->cmd_vr_idx = 0; |
| 162 | cfg_size = sizeof(vdev->config.net); |
| 163 | break; |
| 164 | case VIRTIO_ID_BLOCK: |
| 165 | vdev->nr_vqs = 1; |
| 166 | vdev->cmd_vr_idx = 0; |
| 167 | cfg_size = sizeof(vdev->config.blk); |
| 168 | break; |
| 169 | case VIRTIO_ID_SCSI: |
| 170 | vdev->nr_vqs = 3; |
| 171 | vdev->cmd_vr_idx = VR_REQUEST; |
| 172 | cfg_size = sizeof(vdev->config.scsi); |
| 173 | break; |
| 174 | default: |
| 175 | puts("Unsupported virtio device"); |
| 176 | return -ENODEV; |
| 177 | } |
| 178 | |
| 179 | status |= VIRTIO_CONFIG_S_DRIVER; |
| 180 | if (run_ccw(vdev, CCW_CMD_WRITE_STATUS, &status, sizeof(status), false)) { |
| 181 | puts("Could not write DRIVER status to host"); |
| 182 | return -EIO; |
| 183 | } |
| 184 | |
| 185 | /* Feature negotiation */ |
| 186 | for (i = 0; i < ARRAY_SIZE(vdev->guest_features); i++) { |
| 187 | feats.features = 0; |
| 188 | feats.index = i; |
| 189 | if (run_ccw(vdev, CCW_CMD_READ_FEAT, &feats, sizeof(feats), false)) { |
| 190 | puts("Could not get features bits"); |
| 191 | return -EIO; |
| 192 | } |
| 193 | |
| 194 | vdev->guest_features[i] &= bswap32(feats.features); |
| 195 | feats.features = bswap32(vdev->guest_features[i]); |
| 196 | if (run_ccw(vdev, CCW_CMD_WRITE_FEAT, &feats, sizeof(feats), false)) { |
| 197 | puts("Could not set features bits"); |
| 198 | return -EIO; |
| 199 | } |
| 200 | } |
| 201 | |
| 202 | if (run_ccw(vdev, CCW_CMD_READ_CONF, &vdev->config, cfg_size, false)) { |
| 203 | puts("Could not get virtio device configuration"); |
| 204 | return -EIO; |
| 205 | } |
| 206 | |
| 207 | for (i = 0; i < vdev->nr_vqs; i++) { |
| 208 | VqInfo info = { |
| 209 | .queue = (unsigned long long) virtio_get_ring_area(i), |
| 210 | .align = KVM_S390_VIRTIO_RING_ALIGN, |
| 211 | .index = i, |
| 212 | .num = 0, |
| 213 | }; |
| 214 | VqConfig config = { |
| 215 | .index = i, |
| 216 | .num = 0, |
| 217 | }; |
| 218 | |
| 219 | if (run_ccw(vdev, CCW_CMD_READ_VQ_CONF, &config, sizeof(config), |
| 220 | false)) { |
| 221 | puts("Could not get virtio device VQ config"); |
| 222 | return -EIO; |
| 223 | } |
| 224 | info.num = config.num; |
| 225 | vring_init(&vdev->vrings[i], &info); |
| 226 | if (run_ccw(vdev, CCW_CMD_SET_VQ, &info, sizeof(info), false)) { |
| 227 | puts("Cannot set VQ info"); |
| 228 | return -EIO; |
| 229 | } |
| 230 | } |
| 231 | |
| 232 | status |= VIRTIO_CONFIG_S_DRIVER_OK; |
| 233 | if (run_ccw(vdev, CCW_CMD_WRITE_STATUS, &status, sizeof(status), false)) { |
| 234 | puts("Could not write DRIVER_OK status to host"); |
| 235 | return -EIO; |
| 236 | } |
| 237 | |
| 238 | return 0; |
| 239 | } |