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 "block/scsi.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 void virtio_scsi_data_plane_handle_cmd(VirtIODevice *vdev, 53 VirtQueue *vq) 54 { 55 VirtIOSCSI *s = (VirtIOSCSI *)vdev; 56 57 assert(s->ctx && s->dataplane_started); 58 virtio_scsi_handle_cmd_vq(s, vq); 59 } 60 61 static void virtio_scsi_data_plane_handle_ctrl(VirtIODevice *vdev, 62 VirtQueue *vq) 63 { 64 VirtIOSCSI *s = VIRTIO_SCSI(vdev); 65 66 assert(s->ctx && s->dataplane_started); 67 virtio_scsi_handle_ctrl_vq(s, vq); 68 } 69 70 static void virtio_scsi_data_plane_handle_event(VirtIODevice *vdev, 71 VirtQueue *vq) 72 { 73 VirtIOSCSI *s = VIRTIO_SCSI(vdev); 74 75 assert(s->ctx && s->dataplane_started); 76 virtio_scsi_handle_event_vq(s, vq); 77 } 78 79 static int virtio_scsi_vring_init(VirtIOSCSI *s, VirtQueue *vq, int n, 80 void (*fn)(VirtIODevice *vdev, VirtQueue *vq)) 81 { 82 BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s))); 83 int rc; 84 85 /* Set up virtqueue notify */ 86 rc = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), n, true); 87 if (rc != 0) { 88 fprintf(stderr, "virtio-scsi: Failed to set host notifier (%d)\n", 89 rc); 90 s->dataplane_fenced = true; 91 return rc; 92 } 93 94 virtio_queue_aio_set_host_notifier_handler(vq, s->ctx, fn); 95 return 0; 96 } 97 98 void virtio_scsi_dataplane_notify(VirtIODevice *vdev, VirtIOSCSIReq *req) 99 { 100 if (virtio_should_notify(vdev, req->vq)) { 101 event_notifier_set(virtio_queue_get_guest_notifier(req->vq)); 102 } 103 } 104 105 /* assumes s->ctx held */ 106 static void virtio_scsi_clear_aio(VirtIOSCSI *s) 107 { 108 VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s); 109 int i; 110 111 virtio_queue_aio_set_host_notifier_handler(vs->ctrl_vq, s->ctx, NULL); 112 virtio_queue_aio_set_host_notifier_handler(vs->event_vq, s->ctx, NULL); 113 for (i = 0; i < vs->conf.num_queues; i++) { 114 virtio_queue_aio_set_host_notifier_handler(vs->cmd_vqs[i], s->ctx, NULL); 115 } 116 } 117 118 /* Context: QEMU global mutex held */ 119 int virtio_scsi_dataplane_start(VirtIODevice *vdev) 120 { 121 int i; 122 int rc; 123 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 124 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 125 VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev); 126 VirtIOSCSI *s = VIRTIO_SCSI(vdev); 127 128 if (s->dataplane_started || 129 s->dataplane_starting || 130 s->dataplane_fenced) { 131 return 0; 132 } 133 134 s->dataplane_starting = true; 135 136 /* Set up guest notifier (irq) */ 137 rc = k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, true); 138 if (rc != 0) { 139 fprintf(stderr, "virtio-scsi: Failed to set guest notifiers (%d), " 140 "ensure -enable-kvm is set\n", rc); 141 goto fail_guest_notifiers; 142 } 143 144 aio_context_acquire(s->ctx); 145 rc = virtio_scsi_vring_init(s, vs->ctrl_vq, 0, 146 virtio_scsi_data_plane_handle_ctrl); 147 if (rc) { 148 goto fail_vrings; 149 } 150 rc = virtio_scsi_vring_init(s, vs->event_vq, 1, 151 virtio_scsi_data_plane_handle_event); 152 if (rc) { 153 goto fail_vrings; 154 } 155 for (i = 0; i < vs->conf.num_queues; i++) { 156 rc = virtio_scsi_vring_init(s, vs->cmd_vqs[i], i + 2, 157 virtio_scsi_data_plane_handle_cmd); 158 if (rc) { 159 goto fail_vrings; 160 } 161 } 162 163 s->dataplane_starting = false; 164 s->dataplane_started = true; 165 aio_context_release(s->ctx); 166 return 0; 167 168 fail_vrings: 169 virtio_scsi_clear_aio(s); 170 aio_context_release(s->ctx); 171 for (i = 0; i < vs->conf.num_queues + 2; i++) { 172 virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false); 173 } 174 k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, false); 175 fail_guest_notifiers: 176 s->dataplane_fenced = true; 177 s->dataplane_starting = false; 178 s->dataplane_started = true; 179 return -ENOSYS; 180 } 181 182 /* Context: QEMU global mutex held */ 183 void virtio_scsi_dataplane_stop(VirtIODevice *vdev) 184 { 185 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 186 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 187 VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev); 188 VirtIOSCSI *s = VIRTIO_SCSI(vdev); 189 int i; 190 191 if (!s->dataplane_started || s->dataplane_stopping) { 192 return; 193 } 194 195 /* Better luck next time. */ 196 if (s->dataplane_fenced) { 197 s->dataplane_fenced = false; 198 s->dataplane_started = false; 199 return; 200 } 201 s->dataplane_stopping = true; 202 203 aio_context_acquire(s->ctx); 204 virtio_scsi_clear_aio(s); 205 aio_context_release(s->ctx); 206 207 blk_drain_all(); /* ensure there are no in-flight requests */ 208 209 for (i = 0; i < vs->conf.num_queues + 2; i++) { 210 virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false); 211 } 212 213 /* Clean up guest notifier (irq) */ 214 k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, false); 215 s->dataplane_stopping = false; 216 s->dataplane_started = false; 217 } 218