1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
|
/*
* 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"
/* 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->ioeventfd_started) {
fprintf(stderr, "virtio-scsi: Failed to set iothread "
"(transport does not support notifiers)");
exit(1);
}
}
static void virtio_scsi_data_plane_handle_cmd(VirtIODevice *vdev,
VirtQueue *vq)
{
VirtIOSCSI *s = (VirtIOSCSI *)vdev;
assert(s->ctx && s->dataplane_started);
virtio_scsi_handle_cmd_vq(s, vq);
}
static void virtio_scsi_data_plane_handle_ctrl(VirtIODevice *vdev,
VirtQueue *vq)
{
VirtIOSCSI *s = VIRTIO_SCSI(vdev);
assert(s->ctx && s->dataplane_started);
virtio_scsi_handle_ctrl_vq(s, vq);
}
static void virtio_scsi_data_plane_handle_event(VirtIODevice *vdev,
VirtQueue *vq)
{
VirtIOSCSI *s = VIRTIO_SCSI(vdev);
assert(s->ctx && s->dataplane_started);
virtio_scsi_handle_event_vq(s, vq);
}
static int virtio_scsi_vring_init(VirtIOSCSI *s, VirtQueue *vq, int n,
void (*fn)(VirtIODevice *vdev, VirtQueue *vq))
{
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s)));
int rc;
/* Set up virtqueue notify */
rc = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), 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, fn);
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, NULL);
virtio_queue_aio_set_host_notifier_handler(vs->event_vq, s->ctx, NULL);
for (i = 0; i < vs->conf.num_queues; i++) {
virtio_queue_aio_set_host_notifier_handler(vs->cmd_vqs[i], s->ctx, 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);
goto fail_guest_notifiers;
}
aio_context_acquire(s->ctx);
rc = virtio_scsi_vring_init(s, vs->ctrl_vq, 0,
virtio_scsi_data_plane_handle_ctrl);
if (rc) {
goto fail_vrings;
}
rc = virtio_scsi_vring_init(s, vs->event_vq, 1,
virtio_scsi_data_plane_handle_event);
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,
virtio_scsi_data_plane_handle_cmd);
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++) {
virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), 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++) {
virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), 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;
}
|
