diff options
Diffstat (limited to 'hw/scsi/virtio-scsi-dataplane.c')
| -rw-r--r-- | hw/scsi/virtio-scsi-dataplane.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c new file mode 100644 index 0000000000..b778e051f8 --- /dev/null +++ b/hw/scsi/virtio-scsi-dataplane.c @@ -0,0 +1,229 @@ +/* + * Virtio SCSI dataplane + * + * Copyright Red Hat, Inc. 2014 + * + * Authors: + * Fam Zheng <famz@redhat.com> + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + * + */ + +#include "hw/virtio/virtio-scsi.h" +#include "qemu/error-report.h" +#include <hw/scsi/scsi.h> +#include <block/scsi.h> +#include <hw/virtio/virtio-bus.h> +#include "hw/virtio/virtio-access.h" +#include "stdio.h" + +/* Context: QEMU global mutex held */ +void virtio_scsi_set_iothread(VirtIOSCSI *s, IOThread *iothread) +{ + BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s))); + VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); + VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s); + + assert(!s->ctx); + s->ctx = iothread_get_aio_context(vs->conf.iothread); + + /* Don't try if transport does not support notifiers. */ + if (!k->set_guest_notifiers || !k->set_host_notifier) { + fprintf(stderr, "virtio-scsi: Failed to set iothread " + "(transport does not support notifiers)"); + exit(1); + } +} + +static VirtIOSCSIVring *virtio_scsi_vring_init(VirtIOSCSI *s, + VirtQueue *vq, + EventNotifierHandler *handler, + int n) +{ + BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s))); + VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); + VirtIOSCSIVring *r = g_slice_new(VirtIOSCSIVring); + + /* Set up virtqueue notify */ + if (k->set_host_notifier(qbus->parent, n, true) != 0) { + fprintf(stderr, "virtio-scsi: Failed to set host notifier\n"); + exit(1); + } + r->host_notifier = *virtio_queue_get_host_notifier(vq); + r->guest_notifier = *virtio_queue_get_guest_notifier(vq); + aio_set_event_notifier(s->ctx, &r->host_notifier, handler); + + r->parent = s; + + if (!vring_setup(&r->vring, VIRTIO_DEVICE(s), n)) { + fprintf(stderr, "virtio-scsi: VRing setup failed\n"); + exit(1); + } + return r; +} + +VirtIOSCSIReq *virtio_scsi_pop_req_vring(VirtIOSCSI *s, + VirtIOSCSIVring *vring) +{ + VirtIOSCSIReq *req = virtio_scsi_init_req(s, NULL); + int r; + + req->vring = vring; + r = vring_pop((VirtIODevice *)s, &vring->vring, &req->elem); + if (r < 0) { + virtio_scsi_free_req(req); + req = NULL; + } + return req; +} + +void virtio_scsi_vring_push_notify(VirtIOSCSIReq *req) +{ + vring_push(&req->vring->vring, &req->elem, + req->qsgl.size + req->resp_iov.size); + event_notifier_set(&req->vring->guest_notifier); +} + +static void virtio_scsi_iothread_handle_ctrl(EventNotifier *notifier) +{ + VirtIOSCSIVring *vring = container_of(notifier, + VirtIOSCSIVring, host_notifier); + VirtIOSCSI *s = VIRTIO_SCSI(vring->parent); + VirtIOSCSIReq *req; + + event_notifier_test_and_clear(notifier); + while ((req = virtio_scsi_pop_req_vring(s, vring))) { + virtio_scsi_handle_ctrl_req(s, req); + } +} + +static void virtio_scsi_iothread_handle_event(EventNotifier *notifier) +{ + VirtIOSCSIVring *vring = container_of(notifier, + VirtIOSCSIVring, host_notifier); + VirtIOSCSI *s = vring->parent; + VirtIODevice *vdev = VIRTIO_DEVICE(s); + + event_notifier_test_and_clear(notifier); + + if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) { + return; + } + + if (s->events_dropped) { + virtio_scsi_push_event(s, NULL, VIRTIO_SCSI_T_NO_EVENT, 0); + } +} + +static void virtio_scsi_iothread_handle_cmd(EventNotifier *notifier) +{ + VirtIOSCSIVring *vring = container_of(notifier, + VirtIOSCSIVring, host_notifier); + VirtIOSCSI *s = (VirtIOSCSI *)vring->parent; + VirtIOSCSIReq *req, *next; + QTAILQ_HEAD(, VirtIOSCSIReq) reqs = QTAILQ_HEAD_INITIALIZER(reqs); + + event_notifier_test_and_clear(notifier); + while ((req = virtio_scsi_pop_req_vring(s, vring))) { + if (virtio_scsi_handle_cmd_req_prepare(s, req)) { + QTAILQ_INSERT_TAIL(&reqs, req, next); + } + } + + QTAILQ_FOREACH_SAFE(req, &reqs, next, next) { + virtio_scsi_handle_cmd_req_submit(s, req); + } +} + +/* Context: QEMU global mutex held */ +void virtio_scsi_dataplane_start(VirtIOSCSI *s) +{ + int i; + int rc; + BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s))); + VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); + VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s); + + if (s->dataplane_started || + s->dataplane_starting || + s->ctx != iothread_get_aio_context(vs->conf.iothread)) { + return; + } + + s->dataplane_starting = true; + + /* Set up guest notifier (irq) */ + rc = k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, true); + if (rc != 0) { + fprintf(stderr, "virtio-scsi: Failed to set guest notifiers, " + "ensure -enable-kvm is set\n"); + exit(1); + } + + aio_context_acquire(s->ctx); + s->ctrl_vring = virtio_scsi_vring_init(s, vs->ctrl_vq, + virtio_scsi_iothread_handle_ctrl, + 0); + s->event_vring = virtio_scsi_vring_init(s, vs->event_vq, + virtio_scsi_iothread_handle_event, + 1); + s->cmd_vrings = g_malloc0(sizeof(VirtIOSCSIVring) * vs->conf.num_queues); + for (i = 0; i < vs->conf.num_queues; i++) { + s->cmd_vrings[i] = + virtio_scsi_vring_init(s, vs->cmd_vqs[i], + virtio_scsi_iothread_handle_cmd, + i + 2); + } + + aio_context_release(s->ctx); + s->dataplane_starting = false; + s->dataplane_started = true; +} + +/* Context: QEMU global mutex held */ +void virtio_scsi_dataplane_stop(VirtIOSCSI *s) +{ + BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s))); + VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); + VirtIODevice *vdev = VIRTIO_DEVICE(s); + VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s); + int i; + + if (!s->dataplane_started || s->dataplane_stopping) { + return; + } + s->dataplane_stopping = true; + assert(s->ctx == iothread_get_aio_context(vs->conf.iothread)); + + aio_context_acquire(s->ctx); + + aio_set_event_notifier(s->ctx, &s->ctrl_vring->host_notifier, NULL); + aio_set_event_notifier(s->ctx, &s->event_vring->host_notifier, NULL); + for (i = 0; i < vs->conf.num_queues; i++) { + aio_set_event_notifier(s->ctx, &s->cmd_vrings[i]->host_notifier, NULL); + } + + bdrv_drain_all(); /* ensure there are no in-flight requests */ + + aio_context_release(s->ctx); + + /* Sync vring state back to virtqueue so that non-dataplane request + * processing can continue when we disable the host notifier below. + */ + vring_teardown(&s->ctrl_vring->vring, vdev, 0); + vring_teardown(&s->event_vring->vring, vdev, 1); + for (i = 0; i < vs->conf.num_queues; i++) { + vring_teardown(&s->cmd_vrings[i]->vring, vdev, 2 + i); + } + + for (i = 0; i < vs->conf.num_queues + 2; i++) { + k->set_host_notifier(qbus->parent, i, false); + } + + /* Clean up guest notifier (irq) */ + k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, false); + s->dataplane_stopping = false; + s->dataplane_started = false; +} |