1 /* 2 * Virtio SCSI dataplane 3 * 4 * Copyright Red Hat, Inc. 2014 5 * 6 * Authors: 7 * Fam Zheng <famz@redhat.com> 8 * 9 * This work is licensed under the terms of the GNU GPL, version 2 or later. 10 * See the COPYING file in the top-level directory. 11 * 12 */ 13 14 #include "qemu/osdep.h" 15 #include "qapi/error.h" 16 #include "hw/virtio/virtio-scsi.h" 17 #include "qemu/error-report.h" 18 #include "sysemu/block-backend.h" 19 #include "hw/scsi/scsi.h" 20 #include "scsi/constants.h" 21 #include "hw/virtio/virtio-bus.h" 22 #include "hw/virtio/virtio-access.h" 23 24 /* Context: QEMU global mutex held */ 25 void virtio_scsi_dataplane_setup(VirtIOSCSI *s, Error **errp) 26 { 27 VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s); 28 VirtIODevice *vdev = VIRTIO_DEVICE(s); 29 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 30 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 31 32 if (vs->conf.iothread) { 33 if (!k->set_guest_notifiers || !k->ioeventfd_assign) { 34 error_setg(errp, 35 "device is incompatible with iothread " 36 "(transport does not support notifiers)"); 37 return; 38 } 39 if (!virtio_device_ioeventfd_enabled(vdev)) { 40 error_setg(errp, "ioeventfd is required for iothread"); 41 return; 42 } 43 s->ctx = iothread_get_aio_context(vs->conf.iothread); 44 } else { 45 if (!virtio_device_ioeventfd_enabled(vdev)) { 46 return; 47 } 48 s->ctx = qemu_get_aio_context(); 49 } 50 } 51 52 static bool virtio_scsi_data_plane_handle_cmd(VirtIODevice *vdev, 53 VirtQueue *vq) 54 { 55 bool progress = false; 56 VirtIOSCSI *s = VIRTIO_SCSI(vdev); 57 58 virtio_scsi_acquire(s); 59 if (!s->dataplane_fenced) { 60 assert(s->ctx && s->dataplane_started); 61 progress = virtio_scsi_handle_cmd_vq(s, vq); 62 } 63 virtio_scsi_release(s); 64 return progress; 65 } 66 67 static bool virtio_scsi_data_plane_handle_ctrl(VirtIODevice *vdev, 68 VirtQueue *vq) 69 { 70 bool progress = false; 71 VirtIOSCSI *s = VIRTIO_SCSI(vdev); 72 73 virtio_scsi_acquire(s); 74 if (!s->dataplane_fenced) { 75 assert(s->ctx && s->dataplane_started); 76 progress = virtio_scsi_handle_ctrl_vq(s, vq); 77 } 78 virtio_scsi_release(s); 79 return progress; 80 } 81 82 static bool virtio_scsi_data_plane_handle_event(VirtIODevice *vdev, 83 VirtQueue *vq) 84 { 85 bool progress = false; 86 VirtIOSCSI *s = VIRTIO_SCSI(vdev); 87 88 virtio_scsi_acquire(s); 89 if (!s->dataplane_fenced) { 90 assert(s->ctx && s->dataplane_started); 91 progress = virtio_scsi_handle_event_vq(s, vq); 92 } 93 virtio_scsi_release(s); 94 return progress; 95 } 96 97 static int virtio_scsi_vring_init(VirtIOSCSI *s, VirtQueue *vq, int n, 98 VirtIOHandleAIOOutput fn) 99 { 100 BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s))); 101 int rc; 102 103 /* Set up virtqueue notify */ 104 rc = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), n, true); 105 if (rc != 0) { 106 fprintf(stderr, "virtio-scsi: Failed to set host notifier (%d)\n", 107 rc); 108 s->dataplane_fenced = true; 109 return rc; 110 } 111 112 virtio_queue_aio_set_host_notifier_handler(vq, s->ctx, fn); 113 return 0; 114 } 115 116 /* Context: BH in IOThread */ 117 static void virtio_scsi_dataplane_stop_bh(void *opaque) 118 { 119 VirtIOSCSI *s = opaque; 120 VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s); 121 int i; 122 123 virtio_queue_aio_set_host_notifier_handler(vs->ctrl_vq, s->ctx, NULL); 124 virtio_queue_aio_set_host_notifier_handler(vs->event_vq, s->ctx, NULL); 125 for (i = 0; i < vs->conf.num_queues; i++) { 126 virtio_queue_aio_set_host_notifier_handler(vs->cmd_vqs[i], s->ctx, NULL); 127 } 128 } 129 130 /* Context: QEMU global mutex held */ 131 int virtio_scsi_dataplane_start(VirtIODevice *vdev) 132 { 133 int i; 134 int rc; 135 int vq_init_count = 0; 136 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 137 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 138 VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev); 139 VirtIOSCSI *s = VIRTIO_SCSI(vdev); 140 141 if (s->dataplane_started || 142 s->dataplane_starting || 143 s->dataplane_fenced) { 144 return 0; 145 } 146 147 s->dataplane_starting = true; 148 149 /* Set up guest notifier (irq) */ 150 rc = k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, true); 151 if (rc != 0) { 152 error_report("virtio-scsi: Failed to set guest notifiers (%d), " 153 "ensure -accel kvm is set.", rc); 154 goto fail_guest_notifiers; 155 } 156 157 aio_context_acquire(s->ctx); 158 rc = virtio_scsi_vring_init(s, vs->ctrl_vq, 0, 159 virtio_scsi_data_plane_handle_ctrl); 160 if (rc) { 161 goto fail_vrings; 162 } 163 164 vq_init_count++; 165 rc = virtio_scsi_vring_init(s, vs->event_vq, 1, 166 virtio_scsi_data_plane_handle_event); 167 if (rc) { 168 goto fail_vrings; 169 } 170 171 vq_init_count++; 172 for (i = 0; i < vs->conf.num_queues; i++) { 173 rc = virtio_scsi_vring_init(s, vs->cmd_vqs[i], i + 2, 174 virtio_scsi_data_plane_handle_cmd); 175 if (rc) { 176 goto fail_vrings; 177 } 178 vq_init_count++; 179 } 180 181 s->dataplane_starting = false; 182 s->dataplane_started = true; 183 aio_context_release(s->ctx); 184 return 0; 185 186 fail_vrings: 187 aio_wait_bh_oneshot(s->ctx, virtio_scsi_dataplane_stop_bh, s); 188 aio_context_release(s->ctx); 189 for (i = 0; i < vq_init_count; i++) { 190 virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false); 191 virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), i); 192 } 193 k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, false); 194 fail_guest_notifiers: 195 s->dataplane_fenced = true; 196 s->dataplane_starting = false; 197 s->dataplane_started = true; 198 return -ENOSYS; 199 } 200 201 /* Context: QEMU global mutex held */ 202 void virtio_scsi_dataplane_stop(VirtIODevice *vdev) 203 { 204 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 205 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 206 VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev); 207 VirtIOSCSI *s = VIRTIO_SCSI(vdev); 208 int i; 209 210 if (!s->dataplane_started || s->dataplane_stopping) { 211 return; 212 } 213 214 /* Better luck next time. */ 215 if (s->dataplane_fenced) { 216 s->dataplane_fenced = false; 217 s->dataplane_started = false; 218 return; 219 } 220 s->dataplane_stopping = true; 221 222 aio_context_acquire(s->ctx); 223 aio_wait_bh_oneshot(s->ctx, virtio_scsi_dataplane_stop_bh, s); 224 aio_context_release(s->ctx); 225 226 blk_drain_all(); /* ensure there are no in-flight requests */ 227 228 for (i = 0; i < vs->conf.num_queues + 2; i++) { 229 virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false); 230 virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), i); 231 } 232 233 /* Clean up guest notifier (irq) */ 234 k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, false); 235 s->dataplane_stopping = false; 236 s->dataplane_started = false; 237 } 238