xref: /openbmc/qemu/hw/virtio/vhost-user-fs.c (revision 40f23e4e) 
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-user-fs.h"
24 #include "monitor/monitor.h"
25 #include "sysemu/sysemu.h"
26 
27 static const int user_feature_bits[] = {
28     VIRTIO_F_VERSION_1,
29     VIRTIO_RING_F_INDIRECT_DESC,
30     VIRTIO_RING_F_EVENT_IDX,
31     VIRTIO_F_NOTIFY_ON_EMPTY,
32     VIRTIO_F_RING_PACKED,
33     VIRTIO_F_IOMMU_PLATFORM,
34 
35     VHOST_INVALID_FEATURE_BIT
36 };
37 
38 static void vuf_get_config(VirtIODevice *vdev, uint8_t *config)
39 {
40     VHostUserFS *fs = VHOST_USER_FS(vdev);
41     struct virtio_fs_config fscfg = {};
42 
43     memcpy((char *)fscfg.tag, fs->conf.tag,
44            MIN(strlen(fs->conf.tag) + 1, sizeof(fscfg.tag)));
45 
46     virtio_stl_p(vdev, &fscfg.num_request_queues, fs->conf.num_request_queues);
47 
48     memcpy(config, &fscfg, sizeof(fscfg));
49 }
50 
51 static void vuf_start(VirtIODevice *vdev)
52 {
53     VHostUserFS *fs = VHOST_USER_FS(vdev);
54     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
55     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
56     int ret;
57     int i;
58 
59     if (!k->set_guest_notifiers) {
60         error_report("binding does not support guest notifiers");
61         return;
62     }
63 
64     ret = vhost_dev_enable_notifiers(&fs->vhost_dev, vdev);
65     if (ret < 0) {
66         error_report("Error enabling host notifiers: %d", -ret);
67         return;
68     }
69 
70     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, true);
71     if (ret < 0) {
72         error_report("Error binding guest notifier: %d", -ret);
73         goto err_host_notifiers;
74     }
75 
76     fs->vhost_dev.acked_features = vdev->guest_features;
77     ret = vhost_dev_start(&fs->vhost_dev, vdev);
78     if (ret < 0) {
79         error_report("Error starting vhost: %d", -ret);
80         goto err_guest_notifiers;
81     }
82 
83     /*
84      * guest_notifier_mask/pending not used yet, so just unmask
85      * everything here.  virtio-pci will do the right thing by
86      * enabling/disabling irqfd.
87      */
88     for (i = 0; i < fs->vhost_dev.nvqs; i++) {
89         vhost_virtqueue_mask(&fs->vhost_dev, vdev, i, false);
90     }
91 
92     return;
93 
94 err_guest_notifiers:
95     k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
96 err_host_notifiers:
97     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
98 }
99 
100 static void vuf_stop(VirtIODevice *vdev)
101 {
102     VHostUserFS *fs = VHOST_USER_FS(vdev);
103     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
104     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
105     int ret;
106 
107     if (!k->set_guest_notifiers) {
108         return;
109     }
110 
111     vhost_dev_stop(&fs->vhost_dev, vdev);
112 
113     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
114     if (ret < 0) {
115         error_report("vhost guest notifier cleanup failed: %d", ret);
116         return;
117     }
118 
119     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
120 }
121 
122 static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
123 {
124     VHostUserFS *fs = VHOST_USER_FS(vdev);
125     bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
126 
127     if (!vdev->vm_running) {
128         should_start = false;
129     }
130 
131     if (fs->vhost_dev.started == should_start) {
132         return;
133     }
134 
135     if (should_start) {
136         vuf_start(vdev);
137     } else {
138         vuf_stop(vdev);
139     }
140 }
141 
142 static uint64_t vuf_get_features(VirtIODevice *vdev,
143                                  uint64_t features,
144                                  Error **errp)
145 {
146     VHostUserFS *fs = VHOST_USER_FS(vdev);
147 
148     return vhost_get_features(&fs->vhost_dev, user_feature_bits, features);
149 }
150 
151 static void vuf_handle_output(VirtIODevice *vdev, VirtQueue *vq)
152 {
153     /*
154      * Not normally called; it's the daemon that handles the queue;
155      * however virtio's cleanup path can call this.
156      */
157 }
158 
159 static void vuf_guest_notifier_mask(VirtIODevice *vdev, int idx,
160                                             bool mask)
161 {
162     VHostUserFS *fs = VHOST_USER_FS(vdev);
163 
164     vhost_virtqueue_mask(&fs->vhost_dev, vdev, idx, mask);
165 }
166 
167 static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
168 {
169     VHostUserFS *fs = VHOST_USER_FS(vdev);
170 
171     return vhost_virtqueue_pending(&fs->vhost_dev, idx);
172 }
173 
174 static void vuf_device_realize(DeviceState *dev, Error **errp)
175 {
176     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
177     VHostUserFS *fs = VHOST_USER_FS(dev);
178     unsigned int i;
179     size_t len;
180     int ret;
181 
182     if (!fs->conf.chardev.chr) {
183         error_setg(errp, "missing chardev");
184         return;
185     }
186 
187     if (!fs->conf.tag) {
188         error_setg(errp, "missing tag property");
189         return;
190     }
191     len = strlen(fs->conf.tag);
192     if (len == 0) {
193         error_setg(errp, "tag property cannot be empty");
194         return;
195     }
196     if (len > sizeof_field(struct virtio_fs_config, tag)) {
197         error_setg(errp, "tag property must be %zu bytes or less",
198                    sizeof_field(struct virtio_fs_config, tag));
199         return;
200     }
201 
202     if (fs->conf.num_request_queues == 0) {
203         error_setg(errp, "num-request-queues property must be larger than 0");
204         return;
205     }
206 
207     if (!is_power_of_2(fs->conf.queue_size)) {
208         error_setg(errp, "queue-size property must be a power of 2");
209         return;
210     }
211 
212     if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
213         error_setg(errp, "queue-size property must be %u or smaller",
214                    VIRTQUEUE_MAX_SIZE);
215         return;
216     }
217 
218     if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) {
219         return;
220     }
221 
222     virtio_init(vdev, "vhost-user-fs", VIRTIO_ID_FS,
223                 sizeof(struct virtio_fs_config));
224 
225     /* Hiprio queue */
226     fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
227 
228     /* Request queues */
229     fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues);
230     for (i = 0; i < fs->conf.num_request_queues; i++) {
231         fs->req_vqs[i] = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
232     }
233 
234     /* 1 high prio queue, plus the number configured */
235     fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
236     fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
237     ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
238                          VHOST_BACKEND_TYPE_USER, 0, errp);
239     if (ret < 0) {
240         goto err_virtio;
241     }
242 
243     return;
244 
245 err_virtio:
246     vhost_user_cleanup(&fs->vhost_user);
247     virtio_delete_queue(fs->hiprio_vq);
248     for (i = 0; i < fs->conf.num_request_queues; i++) {
249         virtio_delete_queue(fs->req_vqs[i]);
250     }
251     g_free(fs->req_vqs);
252     virtio_cleanup(vdev);
253     g_free(fs->vhost_dev.vqs);
254     return;
255 }
256 
257 static void vuf_device_unrealize(DeviceState *dev)
258 {
259     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
260     VHostUserFS *fs = VHOST_USER_FS(dev);
261     int i;
262 
263     /* This will stop vhost backend if appropriate. */
264     vuf_set_status(vdev, 0);
265 
266     vhost_dev_cleanup(&fs->vhost_dev);
267 
268     vhost_user_cleanup(&fs->vhost_user);
269 
270     virtio_delete_queue(fs->hiprio_vq);
271     for (i = 0; i < fs->conf.num_request_queues; i++) {
272         virtio_delete_queue(fs->req_vqs[i]);
273     }
274     g_free(fs->req_vqs);
275     virtio_cleanup(vdev);
276     g_free(fs->vhost_dev.vqs);
277     fs->vhost_dev.vqs = NULL;
278 }
279 
280 static const VMStateDescription vuf_vmstate = {
281     .name = "vhost-user-fs",
282     .unmigratable = 1,
283 };
284 
285 static Property vuf_properties[] = {
286     DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
287     DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
288     DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
289                        conf.num_request_queues, 1),
290     DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
291     DEFINE_PROP_END_OF_LIST(),
292 };
293 
294 static void vuf_instance_init(Object *obj)
295 {
296     VHostUserFS *fs = VHOST_USER_FS(obj);
297 
298     device_add_bootindex_property(obj, &fs->bootindex, "bootindex",
299                                   "/filesystem@0", DEVICE(obj));
300 }
301 
302 static void vuf_class_init(ObjectClass *klass, void *data)
303 {
304     DeviceClass *dc = DEVICE_CLASS(klass);
305     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
306 
307     device_class_set_props(dc, vuf_properties);
308     dc->vmsd = &vuf_vmstate;
309     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
310     vdc->realize = vuf_device_realize;
311     vdc->unrealize = vuf_device_unrealize;
312     vdc->get_features = vuf_get_features;
313     vdc->get_config = vuf_get_config;
314     vdc->set_status = vuf_set_status;
315     vdc->guest_notifier_mask = vuf_guest_notifier_mask;
316     vdc->guest_notifier_pending = vuf_guest_notifier_pending;
317 }
318 
319 static const TypeInfo vuf_info = {
320     .name = TYPE_VHOST_USER_FS,
321     .parent = TYPE_VIRTIO_DEVICE,
322     .instance_size = sizeof(VHostUserFS),
323     .instance_init = vuf_instance_init,
324     .class_init = vuf_class_init,
325 };
326 
327 static void vuf_register_types(void)
328 {
329     type_register_static(&vuf_info);
330 }
331 
332 type_init(vuf_register_types)
333