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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 "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 = g_slice_new(VirtIOSCSIVring);
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);
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;
assert(!s->blocker);
error_setg(&s->blocker, "block device is in use by data plane");
/* 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);
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;
}
error_free(s->blocker);
s->blocker = NULL;
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.
*/
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;
}
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