--- /dev/null
+/*
+ * 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 "sysemu/block-backend.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;
+ int rc;
+
+ /* Set up virtqueue notify */
+ rc = k->set_host_notifier(qbus->parent, n, true);
+ if (rc != 0) {
+ fprintf(stderr, "virtio-scsi: Failed to set host notifier (%d)\n",
+ rc);
+ s->dataplane_fenced = true;
+ return NULL;
+ }
+
+ r = g_slice_new(VirtIOSCSIVring);
+ 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");
+ goto fail_vring;
+ }
+ return r;
+
+fail_vring:
+ aio_set_event_notifier(s->ctx, &r->host_notifier, NULL);
+ k->set_host_notifier(qbus->parent, n, false);
+ g_slice_free(VirtIOSCSIVring, r);
+ return NULL;
+}
+
+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)
+{
+ VirtIODevice *vdev = VIRTIO_DEVICE(req->vring->parent);
+
+ vring_push(vdev, &req->vring->vring, &req->elem,
+ req->qsgl.size + req->resp_iov.size);
+
+ if (vring_should_notify(vdev, &req->vring->vring)) {
+ 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);
+ }
+}
+
+/* assumes s->ctx held */
+static void virtio_scsi_clear_aio(VirtIOSCSI *s)
+{
+ VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
+ int i;
+
+ if (s->ctrl_vring) {
+ aio_set_event_notifier(s->ctx, &s->ctrl_vring->host_notifier, NULL);
+ }
+ if (s->event_vring) {
+ aio_set_event_notifier(s->ctx, &s->event_vring->host_notifier, NULL);
+ }
+ if (s->cmd_vrings) {
+ for (i = 0; i < vs->conf.num_queues && s->cmd_vrings[i]; i++) {
+ aio_set_event_notifier(s->ctx, &s->cmd_vrings[i]->host_notifier, NULL);
+ }
+ }
+}
+
+static void virtio_scsi_vring_teardown(VirtIOSCSI *s)
+{
+ VirtIODevice *vdev = VIRTIO_DEVICE(s);
+ VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
+ int i;
+
+ if (s->ctrl_vring) {
+ vring_teardown(&s->ctrl_vring->vring, vdev, 0);
+ g_slice_free(VirtIOSCSIVring, s->ctrl_vring);
+ s->ctrl_vring = NULL;
+ }
+ if (s->event_vring) {
+ vring_teardown(&s->event_vring->vring, vdev, 1);
+ g_slice_free(VirtIOSCSIVring, s->event_vring);
+ s->event_vring = NULL;
+ }
+ if (s->cmd_vrings) {
+ for (i = 0; i < vs->conf.num_queues && s->cmd_vrings[i]; i++) {
+ vring_teardown(&s->cmd_vrings[i]->vring, vdev, 2 + i);
+ g_slice_free(VirtIOSCSIVring, s->cmd_vrings[i]);
+ s->cmd_vrings[i] = NULL;
+ }
+ free(s->cmd_vrings);
+ s->cmd_vrings = NULL;
+ }
+}
+
+/* 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->dataplane_fenced ||
+ 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 (%d), "
+ "ensure -enable-kvm is set\n", rc);
+ s->dataplane_fenced = true;
+ goto fail_guest_notifiers;
+ }
+
+ aio_context_acquire(s->ctx);
+ s->ctrl_vring = virtio_scsi_vring_init(s, vs->ctrl_vq,
+ virtio_scsi_iothread_handle_ctrl,
+ 0);
+ if (!s->ctrl_vring) {
+ goto fail_vrings;
+ }
+ s->event_vring = virtio_scsi_vring_init(s, vs->event_vq,
+ virtio_scsi_iothread_handle_event,
+ 1);
+ if (!s->event_vring) {
+ goto fail_vrings;
+ }
+ s->cmd_vrings = g_new(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);
+ if (!s->cmd_vrings[i]) {
+ goto fail_vrings;
+ }
+ }
+
+ s->dataplane_starting = false;
+ s->dataplane_started = true;
+ aio_context_release(s->ctx);
+ return;
+
+fail_vrings:
+ virtio_scsi_clear_aio(s);
+ aio_context_release(s->ctx);
+ virtio_scsi_vring_teardown(s);
+ for (i = 0; i < vs->conf.num_queues + 2; i++) {
+ k->set_host_notifier(qbus->parent, i, false);
+ }
+ k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, false);
+fail_guest_notifiers:
+ s->dataplane_starting = false;
+}
+
+/* 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);
+ VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
+ int i;
+
+ /* Better luck next time. */
+ if (s->dataplane_fenced) {
+ s->dataplane_fenced = false;
+ return;
+ }
+ 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);
+ }
+
+ blk_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.
+ */
+ virtio_scsi_vring_teardown(s);
+
+ 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;
+}
Code Review / kvmfornfv.git / blobdiff