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 "hw/virtio/virtio-scsi.h" 16 #include "qemu/error-report.h" 17 #include "sysemu/block-backend.h" 18 #include <hw/scsi/scsi.h> 19 #include <block/scsi.h> 20 #include <hw/virtio/virtio-bus.h> 21 #include "hw/virtio/virtio-access.h" 22 #include "stdio.h" 23 24 /* Context: QEMU global mutex held */ 25 void virtio_scsi_set_iothread(VirtIOSCSI *s, IOThread *iothread) 26 { 27 BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s))); 28 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 29 VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s); 30 31 assert(!s->ctx); 32 s->ctx = iothread_get_aio_context(vs->conf.iothread); 33 34 /* Don't try if transport does not support notifiers. */ 35 if (!k->set_guest_notifiers || !k->set_host_notifier) { 36 fprintf(stderr, "virtio-scsi: Failed to set iothread " 37 "(transport does not support notifiers)"); 38 exit(1); 39 } 40 } 41 42 static int virtio_scsi_vring_init(VirtIOSCSI *s, VirtQueue *vq, int n) 43 { 44 BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s))); 45 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 46 int rc; 47 48 /* Set up virtqueue notify */ 49 rc = k->set_host_notifier(qbus->parent, n, true); 50 if (rc != 0) { 51 fprintf(stderr, "virtio-scsi: Failed to set host notifier (%d)\n", 52 rc); 53 s->dataplane_fenced = true; 54 return rc; 55 } 56 57 virtio_queue_aio_set_host_notifier_handler(vq, s->ctx, true, true); 58 return 0; 59 } 60 61 void virtio_scsi_dataplane_notify(VirtIODevice *vdev, VirtIOSCSIReq *req) 62 { 63 if (virtio_should_notify(vdev, req->vq)) { 64 event_notifier_set(virtio_queue_get_guest_notifier(req->vq)); 65 } 66 } 67 68 /* assumes s->ctx held */ 69 static void virtio_scsi_clear_aio(VirtIOSCSI *s) 70 { 71 VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s); 72 int i; 73 74 virtio_queue_aio_set_host_notifier_handler(vs->ctrl_vq, s->ctx, false, false); 75 virtio_queue_aio_set_host_notifier_handler(vs->event_vq, s->ctx, false, false); 76 for (i = 0; i < vs->conf.num_queues; i++) { 77 virtio_queue_aio_set_host_notifier_handler(vs->cmd_vqs[i], s->ctx, false, false); 78 } 79 } 80 81 /* Context: QEMU global mutex held */ 82 void virtio_scsi_dataplane_start(VirtIOSCSI *s) 83 { 84 int i; 85 int rc; 86 BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s))); 87 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 88 VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s); 89 90 if (s->dataplane_started || 91 s->dataplane_starting || 92 s->dataplane_fenced || 93 s->ctx != iothread_get_aio_context(vs->conf.iothread)) { 94 return; 95 } 96 97 s->dataplane_starting = true; 98 99 /* Set up guest notifier (irq) */ 100 rc = k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, true); 101 if (rc != 0) { 102 fprintf(stderr, "virtio-scsi: Failed to set guest notifiers (%d), " 103 "ensure -enable-kvm is set\n", rc); 104 goto fail_guest_notifiers; 105 } 106 107 aio_context_acquire(s->ctx); 108 rc = virtio_scsi_vring_init(s, vs->ctrl_vq, 0); 109 if (rc) { 110 goto fail_vrings; 111 } 112 rc = virtio_scsi_vring_init(s, vs->event_vq, 1); 113 if (rc) { 114 goto fail_vrings; 115 } 116 for (i = 0; i < vs->conf.num_queues; i++) { 117 rc = virtio_scsi_vring_init(s, vs->cmd_vqs[i], i + 2); 118 if (rc) { 119 goto fail_vrings; 120 } 121 } 122 123 s->dataplane_starting = false; 124 s->dataplane_started = true; 125 aio_context_release(s->ctx); 126 return; 127 128 fail_vrings: 129 virtio_scsi_clear_aio(s); 130 aio_context_release(s->ctx); 131 for (i = 0; i < vs->conf.num_queues + 2; i++) { 132 k->set_host_notifier(qbus->parent, i, false); 133 } 134 k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, false); 135 fail_guest_notifiers: 136 s->dataplane_fenced = true; 137 s->dataplane_starting = false; 138 s->dataplane_started = true; 139 } 140 141 /* Context: QEMU global mutex held */ 142 void virtio_scsi_dataplane_stop(VirtIOSCSI *s) 143 { 144 BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s))); 145 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 146 VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s); 147 int i; 148 149 if (!s->dataplane_started || s->dataplane_stopping) { 150 return; 151 } 152 153 /* Better luck next time. */ 154 if (s->dataplane_fenced) { 155 s->dataplane_fenced = false; 156 s->dataplane_started = false; 157 return; 158 } 159 s->dataplane_stopping = true; 160 assert(s->ctx == iothread_get_aio_context(vs->conf.iothread)); 161 162 aio_context_acquire(s->ctx); 163 164 virtio_scsi_clear_aio(s); 165 166 blk_drain_all(); /* ensure there are no in-flight requests */ 167 168 aio_context_release(s->ctx); 169 170 for (i = 0; i < vs->conf.num_queues + 2; i++) { 171 k->set_host_notifier(qbus->parent, i, false); 172 } 173 174 /* Clean up guest notifier (irq) */ 175 k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, false); 176 s->dataplane_stopping = false; 177 s->dataplane_started = false; 178 } 179