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/*
* 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 "qemu/osdep.h"
#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 int virtio_scsi_vring_init(VirtIOSCSI *s, VirtQueue *vq, int n)
{
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
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 rc;
}
virtio_queue_aio_set_host_notifier_handler(vq, s->ctx, true, true);
return 0;
}
void virtio_scsi_dataplane_notify(VirtIODevice *vdev, VirtIOSCSIReq *req)
{
if (virtio_should_notify(vdev, req->vq)) {
event_notifier_set(virtio_queue_get_guest_notifier(req->vq));
}
}
/* assumes s->ctx held */
static void virtio_scsi_clear_aio(VirtIOSCSI *s)
{
VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
int i;
virtio_queue_aio_set_host_notifier_handler(vs->ctrl_vq, s->ctx, false, false);
virtio_queue_aio_set_host_notifier_handler(vs->event_vq, s->ctx, false, false);
for (i = 0; i < vs->conf.num_queues; i++) {
virtio_queue_aio_set_host_notifier_handler(vs->cmd_vqs[i], s->ctx, false, false);
}
}
/* 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);
goto fail_guest_notifiers;
}
aio_context_acquire(s->ctx);
rc = virtio_scsi_vring_init(s, vs->ctrl_vq, 0);
if (rc) {
goto fail_vrings;
}
rc = virtio_scsi_vring_init(s, vs->event_vq, 1);
if (rc) {
goto fail_vrings;
}
for (i = 0; i < vs->conf.num_queues; i++) {
rc = virtio_scsi_vring_init(s, vs->cmd_vqs[i], i + 2);
if (rc) {
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);
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_fenced = true;
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);
VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
int i;
if (!s->dataplane_started || s->dataplane_stopping) {
return;
}
/* Better luck next time. */
if (s->dataplane_fenced) {
s->dataplane_fenced = false;
s->dataplane_started = false;
return;
}
s->dataplane_stopping = true;
assert(s->ctx == iothread_get_aio_context(vs->conf.iothread));
aio_context_acquire(s->ctx);
virtio_scsi_clear_aio(s);
blk_drain_all(); /* ensure there are no in-flight requests */
aio_context_release(s->ctx);
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;
}
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