xref: /openbmc/qemu/hw/virtio/vhost-user-fs.c (revision 0fbb5d2d) 
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     if (idx == VIRTIO_CONFIG_IRQ_IDX) {
165         return;
166     }
167     vhost_virtqueue_mask(&fs->vhost_dev, vdev, idx, mask);
168 }
169 
170 static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
171 {
172     VHostUserFS *fs = VHOST_USER_FS(vdev);
173 
174     if (idx == VIRTIO_CONFIG_IRQ_IDX) {
175         return false;
176     }
177     return vhost_virtqueue_pending(&fs->vhost_dev, idx);
178 }
179 
180 static void vuf_device_realize(DeviceState *dev, Error **errp)
181 {
182     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
183     VHostUserFS *fs = VHOST_USER_FS(dev);
184     unsigned int i;
185     size_t len;
186     int ret;
187 
188     if (!fs->conf.chardev.chr) {
189         error_setg(errp, "missing chardev");
190         return;
191     }
192 
193     if (!fs->conf.tag) {
194         error_setg(errp, "missing tag property");
195         return;
196     }
197     len = strlen(fs->conf.tag);
198     if (len == 0) {
199         error_setg(errp, "tag property cannot be empty");
200         return;
201     }
202     if (len > sizeof_field(struct virtio_fs_config, tag)) {
203         error_setg(errp, "tag property must be %zu bytes or less",
204                    sizeof_field(struct virtio_fs_config, tag));
205         return;
206     }
207 
208     if (fs->conf.num_request_queues == 0) {
209         error_setg(errp, "num-request-queues property must be larger than 0");
210         return;
211     }
212 
213     if (!is_power_of_2(fs->conf.queue_size)) {
214         error_setg(errp, "queue-size property must be a power of 2");
215         return;
216     }
217 
218     if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
219         error_setg(errp, "queue-size property must be %u or smaller",
220                    VIRTQUEUE_MAX_SIZE);
221         return;
222     }
223 
224     if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) {
225         return;
226     }
227 
228     virtio_init(vdev, "vhost-user-fs", VIRTIO_ID_FS,
229                 sizeof(struct virtio_fs_config));
230 
231     /* Hiprio queue */
232     fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
233 
234     /* Request queues */
235     fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues);
236     for (i = 0; i < fs->conf.num_request_queues; i++) {
237         fs->req_vqs[i] = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
238     }
239 
240     /* 1 high prio queue, plus the number configured */
241     fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
242     fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
243     ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
244                          VHOST_BACKEND_TYPE_USER, 0, errp);
245     if (ret < 0) {
246         goto err_virtio;
247     }
248 
249     return;
250 
251 err_virtio:
252     vhost_user_cleanup(&fs->vhost_user);
253     virtio_delete_queue(fs->hiprio_vq);
254     for (i = 0; i < fs->conf.num_request_queues; i++) {
255         virtio_delete_queue(fs->req_vqs[i]);
256     }
257     g_free(fs->req_vqs);
258     virtio_cleanup(vdev);
259     g_free(fs->vhost_dev.vqs);
260     return;
261 }
262 
263 static void vuf_device_unrealize(DeviceState *dev)
264 {
265     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
266     VHostUserFS *fs = VHOST_USER_FS(dev);
267     int i;
268 
269     /* This will stop vhost backend if appropriate. */
270     vuf_set_status(vdev, 0);
271 
272     vhost_dev_cleanup(&fs->vhost_dev);
273 
274     vhost_user_cleanup(&fs->vhost_user);
275 
276     virtio_delete_queue(fs->hiprio_vq);
277     for (i = 0; i < fs->conf.num_request_queues; i++) {
278         virtio_delete_queue(fs->req_vqs[i]);
279     }
280     g_free(fs->req_vqs);
281     virtio_cleanup(vdev);
282     g_free(fs->vhost_dev.vqs);
283     fs->vhost_dev.vqs = NULL;
284 }
285 
286 static const VMStateDescription vuf_vmstate = {
287     .name = "vhost-user-fs",
288     .unmigratable = 1,
289 };
290 
291 static Property vuf_properties[] = {
292     DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
293     DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
294     DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
295                        conf.num_request_queues, 1),
296     DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
297     DEFINE_PROP_END_OF_LIST(),
298 };
299 
300 static void vuf_instance_init(Object *obj)
301 {
302     VHostUserFS *fs = VHOST_USER_FS(obj);
303 
304     device_add_bootindex_property(obj, &fs->bootindex, "bootindex",
305                                   "/filesystem@0", DEVICE(obj));
306 }
307 
308 static void vuf_class_init(ObjectClass *klass, void *data)
309 {
310     DeviceClass *dc = DEVICE_CLASS(klass);
311     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
312 
313     device_class_set_props(dc, vuf_properties);
314     dc->vmsd = &vuf_vmstate;
315     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
316     vdc->realize = vuf_device_realize;
317     vdc->unrealize = vuf_device_unrealize;
318     vdc->get_features = vuf_get_features;
319     vdc->get_config = vuf_get_config;
320     vdc->set_status = vuf_set_status;
321     vdc->guest_notifier_mask = vuf_guest_notifier_mask;
322     vdc->guest_notifier_pending = vuf_guest_notifier_pending;
323 }
324 
325 static const TypeInfo vuf_info = {
326     .name = TYPE_VHOST_USER_FS,
327     .parent = TYPE_VIRTIO_DEVICE,
328     .instance_size = sizeof(VHostUserFS),
329     .instance_init = vuf_instance_init,
330     .class_init = vuf_class_init,
331 };
332 
333 static void vuf_register_types(void)
334 {
335     type_register_static(&vuf_info);
336 }
337 
338 type_init(vuf_register_types)
339