xref: /openbmc/qemu/hw/virtio/vhost-user-fs.c (revision 729cc683) 
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 
26 static void vuf_get_config(VirtIODevice *vdev, uint8_t *config)
27 {
28     VHostUserFS *fs = VHOST_USER_FS(vdev);
29     struct virtio_fs_config fscfg = {};
30 
31     memcpy((char *)fscfg.tag, fs->conf.tag,
32            MIN(strlen(fs->conf.tag) + 1, sizeof(fscfg.tag)));
33 
34     virtio_stl_p(vdev, &fscfg.num_request_queues, fs->conf.num_request_queues);
35 
36     memcpy(config, &fscfg, sizeof(fscfg));
37 }
38 
39 static void vuf_start(VirtIODevice *vdev)
40 {
41     VHostUserFS *fs = VHOST_USER_FS(vdev);
42     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
43     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
44     int ret;
45     int i;
46 
47     if (!k->set_guest_notifiers) {
48         error_report("binding does not support guest notifiers");
49         return;
50     }
51 
52     ret = vhost_dev_enable_notifiers(&fs->vhost_dev, vdev);
53     if (ret < 0) {
54         error_report("Error enabling host notifiers: %d", -ret);
55         return;
56     }
57 
58     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, true);
59     if (ret < 0) {
60         error_report("Error binding guest notifier: %d", -ret);
61         goto err_host_notifiers;
62     }
63 
64     fs->vhost_dev.acked_features = vdev->guest_features;
65     ret = vhost_dev_start(&fs->vhost_dev, vdev);
66     if (ret < 0) {
67         error_report("Error starting vhost: %d", -ret);
68         goto err_guest_notifiers;
69     }
70 
71     /*
72      * guest_notifier_mask/pending not used yet, so just unmask
73      * everything here.  virtio-pci will do the right thing by
74      * enabling/disabling irqfd.
75      */
76     for (i = 0; i < fs->vhost_dev.nvqs; i++) {
77         vhost_virtqueue_mask(&fs->vhost_dev, vdev, i, false);
78     }
79 
80     return;
81 
82 err_guest_notifiers:
83     k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
84 err_host_notifiers:
85     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
86 }
87 
88 static void vuf_stop(VirtIODevice *vdev)
89 {
90     VHostUserFS *fs = VHOST_USER_FS(vdev);
91     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
92     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
93     int ret;
94 
95     if (!k->set_guest_notifiers) {
96         return;
97     }
98 
99     vhost_dev_stop(&fs->vhost_dev, vdev);
100 
101     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
102     if (ret < 0) {
103         error_report("vhost guest notifier cleanup failed: %d", ret);
104         return;
105     }
106 
107     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
108 }
109 
110 static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
111 {
112     VHostUserFS *fs = VHOST_USER_FS(vdev);
113     bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
114 
115     if (!vdev->vm_running) {
116         should_start = false;
117     }
118 
119     if (fs->vhost_dev.started == should_start) {
120         return;
121     }
122 
123     if (should_start) {
124         vuf_start(vdev);
125     } else {
126         vuf_stop(vdev);
127     }
128 }
129 
130 static uint64_t vuf_get_features(VirtIODevice *vdev,
131                                       uint64_t requested_features,
132                                       Error **errp)
133 {
134     /* No feature bits used yet */
135     return requested_features;
136 }
137 
138 static void vuf_handle_output(VirtIODevice *vdev, VirtQueue *vq)
139 {
140     /*
141      * Not normally called; it's the daemon that handles the queue;
142      * however virtio's cleanup path can call this.
143      */
144 }
145 
146 static void vuf_guest_notifier_mask(VirtIODevice *vdev, int idx,
147                                             bool mask)
148 {
149     VHostUserFS *fs = VHOST_USER_FS(vdev);
150 
151     vhost_virtqueue_mask(&fs->vhost_dev, vdev, idx, mask);
152 }
153 
154 static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
155 {
156     VHostUserFS *fs = VHOST_USER_FS(vdev);
157 
158     return vhost_virtqueue_pending(&fs->vhost_dev, idx);
159 }
160 
161 static void vuf_device_realize(DeviceState *dev, Error **errp)
162 {
163     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
164     VHostUserFS *fs = VHOST_USER_FS(dev);
165     unsigned int i;
166     size_t len;
167     int ret;
168 
169     if (!fs->conf.chardev.chr) {
170         error_setg(errp, "missing chardev");
171         return;
172     }
173 
174     if (!fs->conf.tag) {
175         error_setg(errp, "missing tag property");
176         return;
177     }
178     len = strlen(fs->conf.tag);
179     if (len == 0) {
180         error_setg(errp, "tag property cannot be empty");
181         return;
182     }
183     if (len > sizeof_field(struct virtio_fs_config, tag)) {
184         error_setg(errp, "tag property must be %zu bytes or less",
185                    sizeof_field(struct virtio_fs_config, tag));
186         return;
187     }
188 
189     if (fs->conf.num_request_queues == 0) {
190         error_setg(errp, "num-request-queues property must be larger than 0");
191         return;
192     }
193 
194     if (!is_power_of_2(fs->conf.queue_size)) {
195         error_setg(errp, "queue-size property must be a power of 2");
196         return;
197     }
198 
199     if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
200         error_setg(errp, "queue-size property must be %u or smaller",
201                    VIRTQUEUE_MAX_SIZE);
202         return;
203     }
204 
205     if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) {
206         return;
207     }
208 
209     virtio_init(vdev, "vhost-user-fs", VIRTIO_ID_FS,
210                 sizeof(struct virtio_fs_config));
211 
212     /* Hiprio queue */
213     fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
214 
215     /* Request queues */
216     fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues);
217     for (i = 0; i < fs->conf.num_request_queues; i++) {
218         fs->req_vqs[i] = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
219     }
220 
221     /* 1 high prio queue, plus the number configured */
222     fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
223     fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
224     ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
225                          VHOST_BACKEND_TYPE_USER, 0);
226     if (ret < 0) {
227         error_setg_errno(errp, -ret, "vhost_dev_init failed");
228         goto err_virtio;
229     }
230 
231     return;
232 
233 err_virtio:
234     vhost_user_cleanup(&fs->vhost_user);
235     virtio_delete_queue(fs->hiprio_vq);
236     for (i = 0; i < fs->conf.num_request_queues; i++) {
237         virtio_delete_queue(fs->req_vqs[i]);
238     }
239     g_free(fs->req_vqs);
240     virtio_cleanup(vdev);
241     g_free(fs->vhost_dev.vqs);
242     return;
243 }
244 
245 static void vuf_device_unrealize(DeviceState *dev)
246 {
247     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
248     VHostUserFS *fs = VHOST_USER_FS(dev);
249     int i;
250 
251     /* This will stop vhost backend if appropriate. */
252     vuf_set_status(vdev, 0);
253 
254     vhost_dev_cleanup(&fs->vhost_dev);
255 
256     vhost_user_cleanup(&fs->vhost_user);
257 
258     virtio_delete_queue(fs->hiprio_vq);
259     for (i = 0; i < fs->conf.num_request_queues; i++) {
260         virtio_delete_queue(fs->req_vqs[i]);
261     }
262     g_free(fs->req_vqs);
263     virtio_cleanup(vdev);
264     g_free(fs->vhost_dev.vqs);
265     fs->vhost_dev.vqs = NULL;
266 }
267 
268 static const VMStateDescription vuf_vmstate = {
269     .name = "vhost-user-fs",
270     .unmigratable = 1,
271 };
272 
273 static Property vuf_properties[] = {
274     DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
275     DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
276     DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
277                        conf.num_request_queues, 1),
278     DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
279     DEFINE_PROP_END_OF_LIST(),
280 };
281 
282 static void vuf_class_init(ObjectClass *klass, void *data)
283 {
284     DeviceClass *dc = DEVICE_CLASS(klass);
285     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
286 
287     device_class_set_props(dc, vuf_properties);
288     dc->vmsd = &vuf_vmstate;
289     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
290     vdc->realize = vuf_device_realize;
291     vdc->unrealize = vuf_device_unrealize;
292     vdc->get_features = vuf_get_features;
293     vdc->get_config = vuf_get_config;
294     vdc->set_status = vuf_set_status;
295     vdc->guest_notifier_mask = vuf_guest_notifier_mask;
296     vdc->guest_notifier_pending = vuf_guest_notifier_pending;
297 }
298 
299 static const TypeInfo vuf_info = {
300     .name = TYPE_VHOST_USER_FS,
301     .parent = TYPE_VIRTIO_DEVICE,
302     .instance_size = sizeof(VHostUserFS),
303     .class_init = vuf_class_init,
304 };
305 
306 static void vuf_register_types(void)
307 {
308     type_register_static(&vuf_info);
309 }
310 
311 type_init(vuf_register_types)
312