xref: /qemu/hw/virtio/vhost-user-fs.c (revision 2abf0da2) 
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 "sysemu/sysemu.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 
37     VHOST_INVALID_FEATURE_BIT
38 };
39 
40 static void vuf_get_config(VirtIODevice *vdev, uint8_t *config)
41 {
42     VHostUserFS *fs = VHOST_USER_FS(vdev);
43     struct virtio_fs_config fscfg = {};
44 
45     memcpy((char *)fscfg.tag, fs->conf.tag,
46            MIN(strlen(fs->conf.tag) + 1, sizeof(fscfg.tag)));
47 
48     virtio_stl_p(vdev, &fscfg.num_request_queues, fs->conf.num_request_queues);
49 
50     memcpy(config, &fscfg, sizeof(fscfg));
51 }
52 
53 static void vuf_start(VirtIODevice *vdev)
54 {
55     VHostUserFS *fs = VHOST_USER_FS(vdev);
56     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
57     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
58     int ret;
59     int i;
60 
61     if (!k->set_guest_notifiers) {
62         error_report("binding does not support guest notifiers");
63         return;
64     }
65 
66     ret = vhost_dev_enable_notifiers(&fs->vhost_dev, vdev);
67     if (ret < 0) {
68         error_report("Error enabling host notifiers: %d", -ret);
69         return;
70     }
71 
72     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, true);
73     if (ret < 0) {
74         error_report("Error binding guest notifier: %d", -ret);
75         goto err_host_notifiers;
76     }
77 
78     fs->vhost_dev.acked_features = vdev->guest_features;
79     ret = vhost_dev_start(&fs->vhost_dev, vdev, true);
80     if (ret < 0) {
81         error_report("Error starting vhost: %d", -ret);
82         goto err_guest_notifiers;
83     }
84 
85     /*
86      * guest_notifier_mask/pending not used yet, so just unmask
87      * everything here.  virtio-pci will do the right thing by
88      * enabling/disabling irqfd.
89      */
90     for (i = 0; i < fs->vhost_dev.nvqs; i++) {
91         vhost_virtqueue_mask(&fs->vhost_dev, vdev, i, false);
92     }
93 
94     return;
95 
96 err_guest_notifiers:
97     k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
98 err_host_notifiers:
99     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
100 }
101 
102 static void vuf_stop(VirtIODevice *vdev)
103 {
104     VHostUserFS *fs = VHOST_USER_FS(vdev);
105     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
106     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
107     int ret;
108 
109     if (!k->set_guest_notifiers) {
110         return;
111     }
112 
113     vhost_dev_stop(&fs->vhost_dev, vdev, true);
114 
115     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
116     if (ret < 0) {
117         error_report("vhost guest notifier cleanup failed: %d", ret);
118         return;
119     }
120 
121     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
122 }
123 
124 static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
125 {
126     VHostUserFS *fs = VHOST_USER_FS(vdev);
127     bool should_start = virtio_device_should_start(vdev, status);
128 
129     if (vhost_dev_is_started(&fs->vhost_dev) == should_start) {
130         return;
131     }
132 
133     if (should_start) {
134         vuf_start(vdev);
135     } else {
136         vuf_stop(vdev);
137     }
138 }
139 
140 static uint64_t vuf_get_features(VirtIODevice *vdev,
141                                  uint64_t features,
142                                  Error **errp)
143 {
144     VHostUserFS *fs = VHOST_USER_FS(vdev);
145 
146     return vhost_get_features(&fs->vhost_dev, user_feature_bits, features);
147 }
148 
149 static void vuf_handle_output(VirtIODevice *vdev, VirtQueue *vq)
150 {
151     /*
152      * Not normally called; it's the daemon that handles the queue;
153      * however virtio's cleanup path can call this.
154      */
155 }
156 
157 static void vuf_guest_notifier_mask(VirtIODevice *vdev, int idx,
158                                             bool mask)
159 {
160     VHostUserFS *fs = VHOST_USER_FS(vdev);
161 
162     /*
163      * Add the check for configure interrupt, Use VIRTIO_CONFIG_IRQ_IDX -1
164      * as the macro of configure interrupt's IDX, If this driver does not
165      * support, the function will return
166      */
167 
168     if (idx == VIRTIO_CONFIG_IRQ_IDX) {
169         return;
170     }
171     vhost_virtqueue_mask(&fs->vhost_dev, vdev, idx, mask);
172 }
173 
174 static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
175 {
176     VHostUserFS *fs = VHOST_USER_FS(vdev);
177 
178     /*
179      * Add the check for configure interrupt, Use VIRTIO_CONFIG_IRQ_IDX -1
180      * as the macro of configure interrupt's IDX, If this driver does not
181      * support, the function will return
182      */
183 
184     if (idx == VIRTIO_CONFIG_IRQ_IDX) {
185         return false;
186     }
187     return vhost_virtqueue_pending(&fs->vhost_dev, idx);
188 }
189 
190 static void vuf_device_realize(DeviceState *dev, Error **errp)
191 {
192     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
193     VHostUserFS *fs = VHOST_USER_FS(dev);
194     unsigned int i;
195     size_t len;
196     int ret;
197 
198     if (!fs->conf.chardev.chr) {
199         error_setg(errp, "missing chardev");
200         return;
201     }
202 
203     if (!fs->conf.tag) {
204         error_setg(errp, "missing tag property");
205         return;
206     }
207     len = strlen(fs->conf.tag);
208     if (len == 0) {
209         error_setg(errp, "tag property cannot be empty");
210         return;
211     }
212     if (len > sizeof_field(struct virtio_fs_config, tag)) {
213         error_setg(errp, "tag property must be %zu bytes or less",
214                    sizeof_field(struct virtio_fs_config, tag));
215         return;
216     }
217 
218     if (fs->conf.num_request_queues == 0) {
219         error_setg(errp, "num-request-queues property must be larger than 0");
220         return;
221     }
222 
223     if (!is_power_of_2(fs->conf.queue_size)) {
224         error_setg(errp, "queue-size property must be a power of 2");
225         return;
226     }
227 
228     if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
229         error_setg(errp, "queue-size property must be %u or smaller",
230                    VIRTQUEUE_MAX_SIZE);
231         return;
232     }
233 
234     if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) {
235         return;
236     }
237 
238     virtio_init(vdev, VIRTIO_ID_FS, sizeof(struct virtio_fs_config));
239 
240     /* Hiprio queue */
241     fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
242 
243     /* Request queues */
244     fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues);
245     for (i = 0; i < fs->conf.num_request_queues; i++) {
246         fs->req_vqs[i] = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
247     }
248 
249     /* 1 high prio queue, plus the number configured */
250     fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
251     fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
252     ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
253                          VHOST_BACKEND_TYPE_USER, 0, errp);
254     if (ret < 0) {
255         goto err_virtio;
256     }
257 
258     return;
259 
260 err_virtio:
261     vhost_user_cleanup(&fs->vhost_user);
262     virtio_delete_queue(fs->hiprio_vq);
263     for (i = 0; i < fs->conf.num_request_queues; i++) {
264         virtio_delete_queue(fs->req_vqs[i]);
265     }
266     g_free(fs->req_vqs);
267     virtio_cleanup(vdev);
268     g_free(fs->vhost_dev.vqs);
269     return;
270 }
271 
272 static void vuf_device_unrealize(DeviceState *dev)
273 {
274     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
275     VHostUserFS *fs = VHOST_USER_FS(dev);
276     struct vhost_virtqueue *vhost_vqs = fs->vhost_dev.vqs;
277     int i;
278 
279     /* This will stop vhost backend if appropriate. */
280     vuf_set_status(vdev, 0);
281 
282     vhost_dev_cleanup(&fs->vhost_dev);
283 
284     vhost_user_cleanup(&fs->vhost_user);
285 
286     virtio_delete_queue(fs->hiprio_vq);
287     for (i = 0; i < fs->conf.num_request_queues; i++) {
288         virtio_delete_queue(fs->req_vqs[i]);
289     }
290     g_free(fs->req_vqs);
291     virtio_cleanup(vdev);
292     g_free(vhost_vqs);
293 }
294 
295 static struct vhost_dev *vuf_get_vhost(VirtIODevice *vdev)
296 {
297     VHostUserFS *fs = VHOST_USER_FS(vdev);
298     return &fs->vhost_dev;
299 }
300 
301 /**
302  * Fetch the internal state from virtiofsd and save it to `f`.
303  */
304 static int vuf_save_state(QEMUFile *f, void *pv, size_t size,
305                           const VMStateField *field, JSONWriter *vmdesc)
306 {
307     VirtIODevice *vdev = pv;
308     VHostUserFS *fs = VHOST_USER_FS(vdev);
309     Error *local_error = NULL;
310     int ret;
311 
312     ret = vhost_save_backend_state(&fs->vhost_dev, f, &local_error);
313     if (ret < 0) {
314         error_reportf_err(local_error,
315                           "Error saving back-end state of %s device %s "
316                           "(tag: \"%s\"): ",
317                           vdev->name, vdev->parent_obj.canonical_path,
318                           fs->conf.tag ?: "<none>");
319         return ret;
320     }
321 
322     return 0;
323 }
324 
325 /**
326  * Load virtiofsd's internal state from `f` and send it over to virtiofsd.
327  */
328 static int vuf_load_state(QEMUFile *f, void *pv, size_t size,
329                           const VMStateField *field)
330 {
331     VirtIODevice *vdev = pv;
332     VHostUserFS *fs = VHOST_USER_FS(vdev);
333     Error *local_error = NULL;
334     int ret;
335 
336     ret = vhost_load_backend_state(&fs->vhost_dev, f, &local_error);
337     if (ret < 0) {
338         error_reportf_err(local_error,
339                           "Error loading back-end state of %s device %s "
340                           "(tag: \"%s\"): ",
341                           vdev->name, vdev->parent_obj.canonical_path,
342                           fs->conf.tag ?: "<none>");
343         return ret;
344     }
345 
346     return 0;
347 }
348 
349 static bool vuf_is_internal_migration(void *opaque)
350 {
351     /* TODO: Return false when an external migration is requested */
352     return true;
353 }
354 
355 static int vuf_check_migration_support(void *opaque)
356 {
357     VirtIODevice *vdev = opaque;
358     VHostUserFS *fs = VHOST_USER_FS(vdev);
359 
360     if (!vhost_supports_device_state(&fs->vhost_dev)) {
361         error_report("Back-end of %s device %s (tag: \"%s\") does not support "
362                      "migration through qemu",
363                      vdev->name, vdev->parent_obj.canonical_path,
364                      fs->conf.tag ?: "<none>");
365         return -ENOTSUP;
366     }
367 
368     return 0;
369 }
370 
371 static const VMStateDescription vuf_backend_vmstate;
372 
373 static const VMStateDescription vuf_vmstate = {
374     .name = "vhost-user-fs",
375     .version_id = 0,
376     .fields = (const VMStateField[]) {
377         VMSTATE_VIRTIO_DEVICE,
378         VMSTATE_END_OF_LIST()
379     },
380     .subsections = (const VMStateDescription * const []) {
381         &vuf_backend_vmstate,
382         NULL,
383     }
384 };
385 
386 static const VMStateDescription vuf_backend_vmstate = {
387     .name = "vhost-user-fs-backend",
388     .version_id = 0,
389     .needed = vuf_is_internal_migration,
390     .pre_load = vuf_check_migration_support,
391     .pre_save = vuf_check_migration_support,
392     .fields = (const VMStateField[]) {
393         {
394             .name = "back-end",
395             .info = &(const VMStateInfo) {
396                 .name = "virtio-fs back-end state",
397                 .get = vuf_load_state,
398                 .put = vuf_save_state,
399             },
400         },
401         VMSTATE_END_OF_LIST()
402     },
403 };
404 
405 static Property vuf_properties[] = {
406     DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
407     DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
408     DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
409                        conf.num_request_queues, 1),
410     DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
411     DEFINE_PROP_END_OF_LIST(),
412 };
413 
414 static void vuf_instance_init(Object *obj)
415 {
416     VHostUserFS *fs = VHOST_USER_FS(obj);
417 
418     device_add_bootindex_property(obj, &fs->bootindex, "bootindex",
419                                   "/filesystem@0", DEVICE(obj));
420 }
421 
422 static void vuf_class_init(ObjectClass *klass, void *data)
423 {
424     DeviceClass *dc = DEVICE_CLASS(klass);
425     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
426 
427     device_class_set_props(dc, vuf_properties);
428     dc->vmsd = &vuf_vmstate;
429     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
430     vdc->realize = vuf_device_realize;
431     vdc->unrealize = vuf_device_unrealize;
432     vdc->get_features = vuf_get_features;
433     vdc->get_config = vuf_get_config;
434     vdc->set_status = vuf_set_status;
435     vdc->guest_notifier_mask = vuf_guest_notifier_mask;
436     vdc->guest_notifier_pending = vuf_guest_notifier_pending;
437     vdc->get_vhost = vuf_get_vhost;
438 }
439 
440 static const TypeInfo vuf_info = {
441     .name = TYPE_VHOST_USER_FS,
442     .parent = TYPE_VIRTIO_DEVICE,
443     .instance_size = sizeof(VHostUserFS),
444     .instance_init = vuf_instance_init,
445     .class_init = vuf_class_init,
446 };
447 
448 static void vuf_register_types(void)
449 {
450     type_register_static(&vuf_info);
451 }
452 
453 type_init(vuf_register_types)
454