xref: /qemu/hw/virtio/vhost-user-fs.c (revision b2a3cbb8) 
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 
36     VHOST_INVALID_FEATURE_BIT
37 };
38 
39 static void vuf_get_config(VirtIODevice *vdev, uint8_t *config)
40 {
41     VHostUserFS *fs = VHOST_USER_FS(vdev);
42     struct virtio_fs_config fscfg = {};
43 
44     memcpy((char *)fscfg.tag, fs->conf.tag,
45            MIN(strlen(fs->conf.tag) + 1, sizeof(fscfg.tag)));
46 
47     virtio_stl_p(vdev, &fscfg.num_request_queues, fs->conf.num_request_queues);
48 
49     memcpy(config, &fscfg, sizeof(fscfg));
50 }
51 
52 static void vuf_start(VirtIODevice *vdev)
53 {
54     VHostUserFS *fs = VHOST_USER_FS(vdev);
55     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
56     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
57     int ret;
58     int i;
59 
60     if (!k->set_guest_notifiers) {
61         error_report("binding does not support guest notifiers");
62         return;
63     }
64 
65     ret = vhost_dev_enable_notifiers(&fs->vhost_dev, vdev);
66     if (ret < 0) {
67         error_report("Error enabling host notifiers: %d", -ret);
68         return;
69     }
70 
71     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, true);
72     if (ret < 0) {
73         error_report("Error binding guest notifier: %d", -ret);
74         goto err_host_notifiers;
75     }
76 
77     fs->vhost_dev.acked_features = vdev->guest_features;
78     ret = vhost_dev_start(&fs->vhost_dev, vdev);
79     if (ret < 0) {
80         error_report("Error starting vhost: %d", -ret);
81         goto err_guest_notifiers;
82     }
83 
84     /*
85      * guest_notifier_mask/pending not used yet, so just unmask
86      * everything here.  virtio-pci will do the right thing by
87      * enabling/disabling irqfd.
88      */
89     for (i = 0; i < fs->vhost_dev.nvqs; i++) {
90         vhost_virtqueue_mask(&fs->vhost_dev, vdev, i, false);
91     }
92 
93     return;
94 
95 err_guest_notifiers:
96     k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
97 err_host_notifiers:
98     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
99 }
100 
101 static void vuf_stop(VirtIODevice *vdev)
102 {
103     VHostUserFS *fs = VHOST_USER_FS(vdev);
104     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
105     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
106     int ret;
107 
108     if (!k->set_guest_notifiers) {
109         return;
110     }
111 
112     vhost_dev_stop(&fs->vhost_dev, vdev);
113 
114     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
115     if (ret < 0) {
116         error_report("vhost guest notifier cleanup failed: %d", ret);
117         return;
118     }
119 
120     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
121 }
122 
123 static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
124 {
125     VHostUserFS *fs = VHOST_USER_FS(vdev);
126     bool should_start = virtio_device_should_start(vdev, status);
127 
128     if (vhost_dev_is_started(&fs->vhost_dev) == should_start) {
129         return;
130     }
131 
132     if (should_start) {
133         vuf_start(vdev);
134     } else {
135         vuf_stop(vdev);
136     }
137 }
138 
139 static uint64_t vuf_get_features(VirtIODevice *vdev,
140                                  uint64_t features,
141                                  Error **errp)
142 {
143     VHostUserFS *fs = VHOST_USER_FS(vdev);
144 
145     return vhost_get_features(&fs->vhost_dev, user_feature_bits, features);
146 }
147 
148 static void vuf_handle_output(VirtIODevice *vdev, VirtQueue *vq)
149 {
150     /*
151      * Not normally called; it's the daemon that handles the queue;
152      * however virtio's cleanup path can call this.
153      */
154 }
155 
156 static void vuf_guest_notifier_mask(VirtIODevice *vdev, int idx,
157                                             bool mask)
158 {
159     VHostUserFS *fs = VHOST_USER_FS(vdev);
160 
161     vhost_virtqueue_mask(&fs->vhost_dev, vdev, idx, mask);
162 }
163 
164 static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
165 {
166     VHostUserFS *fs = VHOST_USER_FS(vdev);
167 
168     return vhost_virtqueue_pending(&fs->vhost_dev, idx);
169 }
170 
171 static void vuf_device_realize(DeviceState *dev, Error **errp)
172 {
173     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
174     VHostUserFS *fs = VHOST_USER_FS(dev);
175     unsigned int i;
176     size_t len;
177     int ret;
178 
179     if (!fs->conf.chardev.chr) {
180         error_setg(errp, "missing chardev");
181         return;
182     }
183 
184     if (!fs->conf.tag) {
185         error_setg(errp, "missing tag property");
186         return;
187     }
188     len = strlen(fs->conf.tag);
189     if (len == 0) {
190         error_setg(errp, "tag property cannot be empty");
191         return;
192     }
193     if (len > sizeof_field(struct virtio_fs_config, tag)) {
194         error_setg(errp, "tag property must be %zu bytes or less",
195                    sizeof_field(struct virtio_fs_config, tag));
196         return;
197     }
198 
199     if (fs->conf.num_request_queues == 0) {
200         error_setg(errp, "num-request-queues property must be larger than 0");
201         return;
202     }
203 
204     if (!is_power_of_2(fs->conf.queue_size)) {
205         error_setg(errp, "queue-size property must be a power of 2");
206         return;
207     }
208 
209     if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
210         error_setg(errp, "queue-size property must be %u or smaller",
211                    VIRTQUEUE_MAX_SIZE);
212         return;
213     }
214 
215     if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) {
216         return;
217     }
218 
219     virtio_init(vdev, VIRTIO_ID_FS, sizeof(struct virtio_fs_config));
220 
221     /* Hiprio queue */
222     fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
223 
224     /* Request queues */
225     fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues);
226     for (i = 0; i < fs->conf.num_request_queues; i++) {
227         fs->req_vqs[i] = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
228     }
229 
230     /* 1 high prio queue, plus the number configured */
231     fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
232     fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
233     ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
234                          VHOST_BACKEND_TYPE_USER, 0, errp);
235     if (ret < 0) {
236         goto err_virtio;
237     }
238 
239     return;
240 
241 err_virtio:
242     vhost_user_cleanup(&fs->vhost_user);
243     virtio_delete_queue(fs->hiprio_vq);
244     for (i = 0; i < fs->conf.num_request_queues; i++) {
245         virtio_delete_queue(fs->req_vqs[i]);
246     }
247     g_free(fs->req_vqs);
248     virtio_cleanup(vdev);
249     g_free(fs->vhost_dev.vqs);
250     return;
251 }
252 
253 static void vuf_device_unrealize(DeviceState *dev)
254 {
255     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
256     VHostUserFS *fs = VHOST_USER_FS(dev);
257     int i;
258 
259     /* This will stop vhost backend if appropriate. */
260     vuf_set_status(vdev, 0);
261 
262     vhost_dev_cleanup(&fs->vhost_dev);
263 
264     vhost_user_cleanup(&fs->vhost_user);
265 
266     virtio_delete_queue(fs->hiprio_vq);
267     for (i = 0; i < fs->conf.num_request_queues; i++) {
268         virtio_delete_queue(fs->req_vqs[i]);
269     }
270     g_free(fs->req_vqs);
271     virtio_cleanup(vdev);
272     g_free(fs->vhost_dev.vqs);
273     fs->vhost_dev.vqs = NULL;
274 }
275 
276 static struct vhost_dev *vuf_get_vhost(VirtIODevice *vdev)
277 {
278     VHostUserFS *fs = VHOST_USER_FS(vdev);
279     return &fs->vhost_dev;
280 }
281 
282 static const VMStateDescription vuf_vmstate = {
283     .name = "vhost-user-fs",
284     .unmigratable = 1,
285 };
286 
287 static Property vuf_properties[] = {
288     DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
289     DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
290     DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
291                        conf.num_request_queues, 1),
292     DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
293     DEFINE_PROP_END_OF_LIST(),
294 };
295 
296 static void vuf_instance_init(Object *obj)
297 {
298     VHostUserFS *fs = VHOST_USER_FS(obj);
299 
300     device_add_bootindex_property(obj, &fs->bootindex, "bootindex",
301                                   "/filesystem@0", DEVICE(obj));
302 }
303 
304 static void vuf_class_init(ObjectClass *klass, void *data)
305 {
306     DeviceClass *dc = DEVICE_CLASS(klass);
307     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
308 
309     device_class_set_props(dc, vuf_properties);
310     dc->vmsd = &vuf_vmstate;
311     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
312     vdc->realize = vuf_device_realize;
313     vdc->unrealize = vuf_device_unrealize;
314     vdc->get_features = vuf_get_features;
315     vdc->get_config = vuf_get_config;
316     vdc->set_status = vuf_set_status;
317     vdc->guest_notifier_mask = vuf_guest_notifier_mask;
318     vdc->guest_notifier_pending = vuf_guest_notifier_pending;
319     vdc->get_vhost = vuf_get_vhost;
320 }
321 
322 static const TypeInfo vuf_info = {
323     .name = TYPE_VHOST_USER_FS,
324     .parent = TYPE_VIRTIO_DEVICE,
325     .instance_size = sizeof(VHostUserFS),
326     .instance_init = vuf_instance_init,
327     .class_init = vuf_class_init,
328 };
329 
330 static void vuf_register_types(void)
331 {
332     type_register_static(&vuf_info);
333 }
334 
335 type_init(vuf_register_types)
336