1 /*
2 * Vhost-user filesystem virtio device
3 *
4 * Copyright 2018-2019 Red Hat, Inc.
5 *
6 * Authors:
7 * Stefan Hajnoczi <stefanha@redhat.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2 or
10 * (at your option) any later version. See the COPYING file in the
11 * top-level directory.
12 */
13
14 #include "qemu/osdep.h"
15 #include <sys/ioctl.h>
16 #include "standard-headers/linux/virtio_fs.h"
17 #include "qapi/error.h"
18 #include "hw/qdev-properties.h"
19 #include "hw/qdev-properties-system.h"
20 #include "hw/virtio/virtio-bus.h"
21 #include "hw/virtio/virtio-access.h"
22 #include "qemu/error-report.h"
23 #include "hw/virtio/vhost.h"
24 #include "hw/virtio/vhost-user-fs.h"
25 #include "monitor/monitor.h"
26 #include "system/system.h"
27
28 static const int user_feature_bits[] = {
29 VIRTIO_F_VERSION_1,
30 VIRTIO_RING_F_INDIRECT_DESC,
31 VIRTIO_RING_F_EVENT_IDX,
32 VIRTIO_F_NOTIFY_ON_EMPTY,
33 VIRTIO_F_RING_PACKED,
34 VIRTIO_F_IOMMU_PLATFORM,
35 VIRTIO_F_RING_RESET,
36 VIRTIO_F_IN_ORDER,
37 VIRTIO_F_NOTIFICATION_DATA,
38 VHOST_INVALID_FEATURE_BIT
39 };
40
vuf_get_config(VirtIODevice * vdev,uint8_t * config)41 static void vuf_get_config(VirtIODevice *vdev, uint8_t *config)
42 {
43 VHostUserFS *fs = VHOST_USER_FS(vdev);
44 struct virtio_fs_config fscfg = {};
45
46 memcpy((char *)fscfg.tag, fs->conf.tag,
47 MIN(strlen(fs->conf.tag) + 1, sizeof(fscfg.tag)));
48
49 virtio_stl_p(vdev, &fscfg.num_request_queues, fs->conf.num_request_queues);
50
51 memcpy(config, &fscfg, sizeof(fscfg));
52 }
53
vuf_start(VirtIODevice * vdev)54 static void vuf_start(VirtIODevice *vdev)
55 {
56 VHostUserFS *fs = VHOST_USER_FS(vdev);
57 BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
58 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
59 int ret;
60 int i;
61
62 if (!k->set_guest_notifiers) {
63 error_report("binding does not support guest notifiers");
64 return;
65 }
66
67 ret = vhost_dev_enable_notifiers(&fs->vhost_dev, vdev);
68 if (ret < 0) {
69 error_report("Error enabling host notifiers: %d", -ret);
70 return;
71 }
72
73 ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, true);
74 if (ret < 0) {
75 error_report("Error binding guest notifier: %d", -ret);
76 goto err_host_notifiers;
77 }
78
79 fs->vhost_dev.acked_features = vdev->guest_features;
80 ret = vhost_dev_start(&fs->vhost_dev, vdev, true);
81 if (ret < 0) {
82 error_report("Error starting vhost: %d", -ret);
83 goto err_guest_notifiers;
84 }
85
86 /*
87 * guest_notifier_mask/pending not used yet, so just unmask
88 * everything here. virtio-pci will do the right thing by
89 * enabling/disabling irqfd.
90 */
91 for (i = 0; i < fs->vhost_dev.nvqs; i++) {
92 vhost_virtqueue_mask(&fs->vhost_dev, vdev, i, false);
93 }
94
95 return;
96
97 err_guest_notifiers:
98 k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
99 err_host_notifiers:
100 vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
101 }
102
vuf_stop(VirtIODevice * vdev)103 static int vuf_stop(VirtIODevice *vdev)
104 {
105 VHostUserFS *fs = VHOST_USER_FS(vdev);
106 BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
107 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
108 int ret;
109
110 if (!k->set_guest_notifiers) {
111 return 0;
112 }
113
114 ret = vhost_dev_stop(&fs->vhost_dev, vdev, true);
115
116 if (k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false) < 0) {
117 error_report("vhost guest notifier cleanup failed: %d", ret);
118 return -1;
119 }
120
121 vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
122 return ret;
123 }
124
vuf_set_status(VirtIODevice * vdev,uint8_t status)125 static int vuf_set_status(VirtIODevice *vdev, uint8_t status)
126 {
127 VHostUserFS *fs = VHOST_USER_FS(vdev);
128 bool should_start = virtio_device_should_start(vdev, status);
129
130 if (vhost_dev_is_started(&fs->vhost_dev) == should_start) {
131 return 0;
132 }
133
134 if (should_start) {
135 vuf_start(vdev);
136 } else {
137 int ret;
138 ret = vuf_stop(vdev);
139 if (ret < 0) {
140 return ret;
141 }
142 }
143 return 0;
144 }
145
vuf_get_features(VirtIODevice * vdev,uint64_t features,Error ** errp)146 static uint64_t vuf_get_features(VirtIODevice *vdev,
147 uint64_t features,
148 Error **errp)
149 {
150 VHostUserFS *fs = VHOST_USER_FS(vdev);
151
152 return vhost_get_features(&fs->vhost_dev, user_feature_bits, features);
153 }
154
vuf_handle_output(VirtIODevice * vdev,VirtQueue * vq)155 static void vuf_handle_output(VirtIODevice *vdev, VirtQueue *vq)
156 {
157 /*
158 * Not normally called; it's the daemon that handles the queue;
159 * however virtio's cleanup path can call this.
160 */
161 }
162
vuf_guest_notifier_mask(VirtIODevice * vdev,int idx,bool mask)163 static void vuf_guest_notifier_mask(VirtIODevice *vdev, int idx,
164 bool mask)
165 {
166 VHostUserFS *fs = VHOST_USER_FS(vdev);
167
168 /*
169 * Add the check for configure interrupt, Use VIRTIO_CONFIG_IRQ_IDX -1
170 * as the macro of configure interrupt's IDX, If this driver does not
171 * support, the function will return
172 */
173
174 if (idx == VIRTIO_CONFIG_IRQ_IDX) {
175 return;
176 }
177 vhost_virtqueue_mask(&fs->vhost_dev, vdev, idx, mask);
178 }
179
vuf_guest_notifier_pending(VirtIODevice * vdev,int idx)180 static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
181 {
182 VHostUserFS *fs = VHOST_USER_FS(vdev);
183
184 /*
185 * Add the check for configure interrupt, Use VIRTIO_CONFIG_IRQ_IDX -1
186 * as the macro of configure interrupt's IDX, If this driver does not
187 * support, the function will return
188 */
189
190 if (idx == VIRTIO_CONFIG_IRQ_IDX) {
191 return false;
192 }
193 return vhost_virtqueue_pending(&fs->vhost_dev, idx);
194 }
195
vuf_device_realize(DeviceState * dev,Error ** errp)196 static void vuf_device_realize(DeviceState *dev, Error **errp)
197 {
198 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
199 VHostUserFS *fs = VHOST_USER_FS(dev);
200 unsigned int i;
201 size_t len;
202 int ret;
203
204 if (!fs->conf.chardev.chr) {
205 error_setg(errp, "missing chardev");
206 return;
207 }
208
209 if (!fs->conf.tag) {
210 error_setg(errp, "missing tag property");
211 return;
212 }
213 len = strlen(fs->conf.tag);
214 if (len == 0) {
215 error_setg(errp, "tag property cannot be empty");
216 return;
217 }
218 if (len > sizeof_field(struct virtio_fs_config, tag)) {
219 error_setg(errp, "tag property must be %zu bytes or less",
220 sizeof_field(struct virtio_fs_config, tag));
221 return;
222 }
223
224 if (fs->conf.num_request_queues == 0) {
225 error_setg(errp, "num-request-queues property must be larger than 0");
226 return;
227 }
228
229 if (!is_power_of_2(fs->conf.queue_size)) {
230 error_setg(errp, "queue-size property must be a power of 2");
231 return;
232 }
233
234 if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
235 error_setg(errp, "queue-size property must be %u or smaller",
236 VIRTQUEUE_MAX_SIZE);
237 return;
238 }
239
240 if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) {
241 return;
242 }
243
244 virtio_init(vdev, VIRTIO_ID_FS, sizeof(struct virtio_fs_config));
245
246 /* Hiprio queue */
247 fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
248
249 /* Request queues */
250 fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues);
251 for (i = 0; i < fs->conf.num_request_queues; i++) {
252 fs->req_vqs[i] = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
253 }
254
255 /* 1 high prio queue, plus the number configured */
256 fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
257 fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
258 ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
259 VHOST_BACKEND_TYPE_USER, 0, errp);
260 if (ret < 0) {
261 goto err_virtio;
262 }
263
264 return;
265
266 err_virtio:
267 vhost_user_cleanup(&fs->vhost_user);
268 virtio_delete_queue(fs->hiprio_vq);
269 for (i = 0; i < fs->conf.num_request_queues; i++) {
270 virtio_delete_queue(fs->req_vqs[i]);
271 }
272 g_free(fs->req_vqs);
273 virtio_cleanup(vdev);
274 g_free(fs->vhost_dev.vqs);
275 }
276
vuf_device_unrealize(DeviceState * dev)277 static void vuf_device_unrealize(DeviceState *dev)
278 {
279 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
280 VHostUserFS *fs = VHOST_USER_FS(dev);
281 struct vhost_virtqueue *vhost_vqs = fs->vhost_dev.vqs;
282 int i;
283
284 /* This will stop vhost backend if appropriate. */
285 vuf_set_status(vdev, 0);
286
287 vhost_dev_cleanup(&fs->vhost_dev);
288
289 vhost_user_cleanup(&fs->vhost_user);
290
291 virtio_delete_queue(fs->hiprio_vq);
292 for (i = 0; i < fs->conf.num_request_queues; i++) {
293 virtio_delete_queue(fs->req_vqs[i]);
294 }
295 g_free(fs->req_vqs);
296 virtio_cleanup(vdev);
297 g_free(vhost_vqs);
298 }
299
vuf_get_vhost(VirtIODevice * vdev)300 static struct vhost_dev *vuf_get_vhost(VirtIODevice *vdev)
301 {
302 VHostUserFS *fs = VHOST_USER_FS(vdev);
303 return &fs->vhost_dev;
304 }
305
306 /**
307 * Fetch the internal state from virtiofsd and save it to `f`.
308 */
vuf_save_state(QEMUFile * f,void * pv,size_t size,const VMStateField * field,JSONWriter * vmdesc)309 static int vuf_save_state(QEMUFile *f, void *pv, size_t size,
310 const VMStateField *field, JSONWriter *vmdesc)
311 {
312 VirtIODevice *vdev = pv;
313 VHostUserFS *fs = VHOST_USER_FS(vdev);
314 Error *local_error = NULL;
315 int ret;
316
317 ret = vhost_save_backend_state(&fs->vhost_dev, f, &local_error);
318 if (ret < 0) {
319 error_reportf_err(local_error,
320 "Error saving back-end state of %s device %s "
321 "(tag: \"%s\"): ",
322 vdev->name, vdev->parent_obj.canonical_path,
323 fs->conf.tag ?: "<none>");
324 return ret;
325 }
326
327 return 0;
328 }
329
330 /**
331 * Load virtiofsd's internal state from `f` and send it over to virtiofsd.
332 */
vuf_load_state(QEMUFile * f,void * pv,size_t size,const VMStateField * field)333 static int vuf_load_state(QEMUFile *f, void *pv, size_t size,
334 const VMStateField *field)
335 {
336 VirtIODevice *vdev = pv;
337 VHostUserFS *fs = VHOST_USER_FS(vdev);
338 Error *local_error = NULL;
339 int ret;
340
341 ret = vhost_load_backend_state(&fs->vhost_dev, f, &local_error);
342 if (ret < 0) {
343 error_reportf_err(local_error,
344 "Error loading back-end state of %s device %s "
345 "(tag: \"%s\"): ",
346 vdev->name, vdev->parent_obj.canonical_path,
347 fs->conf.tag ?: "<none>");
348 return ret;
349 }
350
351 return 0;
352 }
353
vuf_is_internal_migration(void * opaque)354 static bool vuf_is_internal_migration(void *opaque)
355 {
356 /* TODO: Return false when an external migration is requested */
357 return true;
358 }
359
vuf_check_migration_support(void * opaque)360 static int vuf_check_migration_support(void *opaque)
361 {
362 VirtIODevice *vdev = opaque;
363 VHostUserFS *fs = VHOST_USER_FS(vdev);
364
365 if (!vhost_supports_device_state(&fs->vhost_dev)) {
366 error_report("Back-end of %s device %s (tag: \"%s\") does not support "
367 "migration through qemu",
368 vdev->name, vdev->parent_obj.canonical_path,
369 fs->conf.tag ?: "<none>");
370 return -ENOTSUP;
371 }
372
373 return 0;
374 }
375
376 static const VMStateDescription vuf_backend_vmstate;
377
378 static const VMStateDescription vuf_vmstate = {
379 .name = "vhost-user-fs",
380 .version_id = 0,
381 .fields = (const VMStateField[]) {
382 VMSTATE_VIRTIO_DEVICE,
383 VMSTATE_END_OF_LIST()
384 },
385 .subsections = (const VMStateDescription * const []) {
386 &vuf_backend_vmstate,
387 NULL,
388 }
389 };
390
391 static const VMStateDescription vuf_backend_vmstate = {
392 .name = "vhost-user-fs-backend",
393 .version_id = 0,
394 .needed = vuf_is_internal_migration,
395 .pre_load = vuf_check_migration_support,
396 .pre_save = vuf_check_migration_support,
397 .fields = (const VMStateField[]) {
398 {
399 .name = "back-end",
400 .info = &(const VMStateInfo) {
401 .name = "virtio-fs back-end state",
402 .get = vuf_load_state,
403 .put = vuf_save_state,
404 },
405 },
406 VMSTATE_END_OF_LIST()
407 },
408 };
409
410 static const Property vuf_properties[] = {
411 DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
412 DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
413 DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
414 conf.num_request_queues, 1),
415 DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
416 };
417
vuf_instance_init(Object * obj)418 static void vuf_instance_init(Object *obj)
419 {
420 VHostUserFS *fs = VHOST_USER_FS(obj);
421
422 device_add_bootindex_property(obj, &fs->bootindex, "bootindex",
423 "/filesystem@0", DEVICE(obj));
424 }
425
vuf_class_init(ObjectClass * klass,const void * data)426 static void vuf_class_init(ObjectClass *klass, const void *data)
427 {
428 DeviceClass *dc = DEVICE_CLASS(klass);
429 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
430
431 device_class_set_props(dc, vuf_properties);
432 dc->vmsd = &vuf_vmstate;
433 set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
434 vdc->realize = vuf_device_realize;
435 vdc->unrealize = vuf_device_unrealize;
436 vdc->get_features = vuf_get_features;
437 vdc->get_config = vuf_get_config;
438 vdc->set_status = vuf_set_status;
439 vdc->guest_notifier_mask = vuf_guest_notifier_mask;
440 vdc->guest_notifier_pending = vuf_guest_notifier_pending;
441 vdc->get_vhost = vuf_get_vhost;
442 }
443
444 static const TypeInfo vuf_info = {
445 .name = TYPE_VHOST_USER_FS,
446 .parent = TYPE_VIRTIO_DEVICE,
447 .instance_size = sizeof(VHostUserFS),
448 .instance_init = vuf_instance_init,
449 .class_init = vuf_class_init,
450 };
451
vuf_register_types(void)452 static void vuf_register_types(void)
453 {
454 type_register_static(&vuf_info);
455 }
456
457 type_init(vuf_register_types)
458