xref: /qemu/hw/block/vhost-user-blk.c (revision 06e7772f) 
1 /*
2  * vhost-user-blk host device
3  *
4  * Copyright(C) 2017 Intel Corporation.
5  *
6  * Authors:
7  *  Changpeng Liu <changpeng.liu@intel.com>
8  *
9  * Largely based on the "vhost-user-scsi.c" and "vhost-scsi.c" implemented by:
10  * Felipe Franciosi <felipe@nutanix.com>
11  * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
12  * Nicholas Bellinger <nab@risingtidesystems.com>
13  *
14  * This work is licensed under the terms of the GNU LGPL, version 2 or later.
15  * See the COPYING.LIB file in the top-level directory.
16  *
17  */
18 
19 #include "qemu/osdep.h"
20 #include "qapi/error.h"
21 #include "qemu/error-report.h"
22 #include "qemu/cutils.h"
23 #include "qom/object.h"
24 #include "hw/qdev-core.h"
25 #include "hw/virtio/vhost.h"
26 #include "hw/virtio/vhost-user-blk.h"
27 #include "hw/virtio/virtio.h"
28 #include "hw/virtio/virtio-bus.h"
29 #include "hw/virtio/virtio-access.h"
30 
31 static const int user_feature_bits[] = {
32     VIRTIO_BLK_F_SIZE_MAX,
33     VIRTIO_BLK_F_SEG_MAX,
34     VIRTIO_BLK_F_GEOMETRY,
35     VIRTIO_BLK_F_BLK_SIZE,
36     VIRTIO_BLK_F_TOPOLOGY,
37     VIRTIO_BLK_F_MQ,
38     VIRTIO_BLK_F_RO,
39     VIRTIO_BLK_F_FLUSH,
40     VIRTIO_BLK_F_CONFIG_WCE,
41     VIRTIO_F_VERSION_1,
42     VIRTIO_RING_F_INDIRECT_DESC,
43     VIRTIO_RING_F_EVENT_IDX,
44     VIRTIO_F_NOTIFY_ON_EMPTY,
45     VHOST_INVALID_FEATURE_BIT
46 };
47 
48 static void vhost_user_blk_update_config(VirtIODevice *vdev, uint8_t *config)
49 {
50     VHostUserBlk *s = VHOST_USER_BLK(vdev);
51 
52     memcpy(config, &s->blkcfg, sizeof(struct virtio_blk_config));
53 }
54 
55 static void vhost_user_blk_set_config(VirtIODevice *vdev, const uint8_t *config)
56 {
57     VHostUserBlk *s = VHOST_USER_BLK(vdev);
58     struct virtio_blk_config *blkcfg = (struct virtio_blk_config *)config;
59     int ret;
60 
61     if (blkcfg->wce == s->blkcfg.wce) {
62         return;
63     }
64 
65     ret = vhost_dev_set_config(&s->dev, &blkcfg->wce,
66                                offsetof(struct virtio_blk_config, wce),
67                                sizeof(blkcfg->wce),
68                                VHOST_SET_CONFIG_TYPE_MASTER);
69     if (ret) {
70         error_report("set device config space failed");
71         return;
72     }
73 
74     s->blkcfg.wce = blkcfg->wce;
75 }
76 
77 static int vhost_user_blk_handle_config_change(struct vhost_dev *dev)
78 {
79     int ret;
80     struct virtio_blk_config blkcfg;
81     VHostUserBlk *s = VHOST_USER_BLK(dev->vdev);
82 
83     ret = vhost_dev_get_config(dev, (uint8_t *)&blkcfg,
84                                sizeof(struct virtio_blk_config));
85     if (ret < 0) {
86         error_report("get config space failed");
87         return -1;
88     }
89 
90     /* valid for resize only */
91     if (blkcfg.capacity != s->blkcfg.capacity) {
92         s->blkcfg.capacity = blkcfg.capacity;
93         memcpy(dev->vdev->config, &s->blkcfg, sizeof(struct virtio_blk_config));
94         virtio_notify_config(dev->vdev);
95     }
96 
97     return 0;
98 }
99 
100 const VhostDevConfigOps blk_ops = {
101     .vhost_dev_config_notifier = vhost_user_blk_handle_config_change,
102 };
103 
104 static void vhost_user_blk_start(VirtIODevice *vdev)
105 {
106     VHostUserBlk *s = VHOST_USER_BLK(vdev);
107     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
108     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
109     int i, ret;
110 
111     if (!k->set_guest_notifiers) {
112         error_report("binding does not support guest notifiers");
113         return;
114     }
115 
116     ret = vhost_dev_enable_notifiers(&s->dev, vdev);
117     if (ret < 0) {
118         error_report("Error enabling host notifiers: %d", -ret);
119         return;
120     }
121 
122     ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, true);
123     if (ret < 0) {
124         error_report("Error binding guest notifier: %d", -ret);
125         goto err_host_notifiers;
126     }
127 
128     s->dev.acked_features = vdev->guest_features;
129     ret = vhost_dev_start(&s->dev, vdev);
130     if (ret < 0) {
131         error_report("Error starting vhost: %d", -ret);
132         goto err_guest_notifiers;
133     }
134 
135     /* guest_notifier_mask/pending not used yet, so just unmask
136      * everything here. virtio-pci will do the right thing by
137      * enabling/disabling irqfd.
138      */
139     for (i = 0; i < s->dev.nvqs; i++) {
140         vhost_virtqueue_mask(&s->dev, vdev, i, false);
141     }
142 
143     return;
144 
145 err_guest_notifiers:
146     k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
147 err_host_notifiers:
148     vhost_dev_disable_notifiers(&s->dev, vdev);
149 }
150 
151 static void vhost_user_blk_stop(VirtIODevice *vdev)
152 {
153     VHostUserBlk *s = VHOST_USER_BLK(vdev);
154     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
155     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
156     int ret;
157 
158     if (!k->set_guest_notifiers) {
159         return;
160     }
161 
162     vhost_dev_stop(&s->dev, vdev);
163 
164     ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
165     if (ret < 0) {
166         error_report("vhost guest notifier cleanup failed: %d", ret);
167         return;
168     }
169 
170     vhost_dev_disable_notifiers(&s->dev, vdev);
171 }
172 
173 static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
174 {
175     VHostUserBlk *s = VHOST_USER_BLK(vdev);
176     bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
177 
178     if (!vdev->vm_running) {
179         should_start = false;
180     }
181 
182     if (s->dev.started == should_start) {
183         return;
184     }
185 
186     if (should_start) {
187         vhost_user_blk_start(vdev);
188     } else {
189         vhost_user_blk_stop(vdev);
190     }
191 
192 }
193 
194 static uint64_t vhost_user_blk_get_features(VirtIODevice *vdev,
195                                             uint64_t features,
196                                             Error **errp)
197 {
198     VHostUserBlk *s = VHOST_USER_BLK(vdev);
199 
200     /* Turn on pre-defined features */
201     virtio_add_feature(&features, VIRTIO_BLK_F_SEG_MAX);
202     virtio_add_feature(&features, VIRTIO_BLK_F_GEOMETRY);
203     virtio_add_feature(&features, VIRTIO_BLK_F_TOPOLOGY);
204     virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE);
205     virtio_add_feature(&features, VIRTIO_BLK_F_FLUSH);
206     virtio_add_feature(&features, VIRTIO_BLK_F_RO);
207 
208     if (s->config_wce) {
209         virtio_add_feature(&features, VIRTIO_BLK_F_CONFIG_WCE);
210     }
211     if (s->num_queues > 1) {
212         virtio_add_feature(&features, VIRTIO_BLK_F_MQ);
213     }
214 
215     return vhost_get_features(&s->dev, user_feature_bits, features);
216 }
217 
218 static void vhost_user_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
219 {
220     VHostUserBlk *s = VHOST_USER_BLK(vdev);
221     int i;
222 
223     if (!(virtio_host_has_feature(vdev, VIRTIO_F_VERSION_1) &&
224         !virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1))) {
225         return;
226     }
227 
228     if (s->dev.started) {
229         return;
230     }
231 
232     /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
233      * vhost here instead of waiting for .set_status().
234      */
235     vhost_user_blk_start(vdev);
236 
237     /* Kick right away to begin processing requests already in vring */
238     for (i = 0; i < s->dev.nvqs; i++) {
239         VirtQueue *kick_vq = virtio_get_queue(vdev, i);
240 
241         if (!virtio_queue_get_desc_addr(vdev, i)) {
242             continue;
243         }
244         event_notifier_set(virtio_queue_get_host_notifier(kick_vq));
245     }
246 }
247 
248 static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
249 {
250     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
251     VHostUserBlk *s = VHOST_USER_BLK(vdev);
252     VhostUserState *user;
253     int i, ret;
254 
255     if (!s->chardev.chr) {
256         error_setg(errp, "vhost-user-blk: chardev is mandatory");
257         return;
258     }
259 
260     if (!s->num_queues || s->num_queues > VIRTIO_QUEUE_MAX) {
261         error_setg(errp, "vhost-user-blk: invalid number of IO queues");
262         return;
263     }
264 
265     if (!s->queue_size) {
266         error_setg(errp, "vhost-user-blk: queue size must be non-zero");
267         return;
268     }
269 
270     user = vhost_user_init();
271     if (!user) {
272         error_setg(errp, "vhost-user-blk: failed to init vhost_user");
273         return;
274     }
275 
276     user->chr = &s->chardev;
277     s->vhost_user = user;
278 
279     virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK,
280                 sizeof(struct virtio_blk_config));
281 
282     for (i = 0; i < s->num_queues; i++) {
283         virtio_add_queue(vdev, s->queue_size,
284                          vhost_user_blk_handle_output);
285     }
286 
287     s->dev.nvqs = s->num_queues;
288     s->dev.vqs = g_new(struct vhost_virtqueue, s->dev.nvqs);
289     s->dev.vq_index = 0;
290     s->dev.backend_features = 0;
291 
292     vhost_dev_set_config_notifier(&s->dev, &blk_ops);
293 
294     ret = vhost_dev_init(&s->dev, s->vhost_user, VHOST_BACKEND_TYPE_USER, 0);
295     if (ret < 0) {
296         error_setg(errp, "vhost-user-blk: vhost initialization failed: %s",
297                    strerror(-ret));
298         goto virtio_err;
299     }
300 
301     ret = vhost_dev_get_config(&s->dev, (uint8_t *)&s->blkcfg,
302                               sizeof(struct virtio_blk_config));
303     if (ret < 0) {
304         error_setg(errp, "vhost-user-blk: get block config failed");
305         goto vhost_err;
306     }
307 
308     if (s->blkcfg.num_queues != s->num_queues) {
309         s->blkcfg.num_queues = s->num_queues;
310     }
311 
312     return;
313 
314 vhost_err:
315     vhost_dev_cleanup(&s->dev);
316 virtio_err:
317     g_free(s->dev.vqs);
318     virtio_cleanup(vdev);
319 
320     vhost_user_cleanup(user);
321     g_free(user);
322     s->vhost_user = NULL;
323 }
324 
325 static void vhost_user_blk_device_unrealize(DeviceState *dev, Error **errp)
326 {
327     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
328     VHostUserBlk *s = VHOST_USER_BLK(dev);
329 
330     vhost_user_blk_set_status(vdev, 0);
331     vhost_dev_cleanup(&s->dev);
332     g_free(s->dev.vqs);
333     virtio_cleanup(vdev);
334 
335     if (s->vhost_user) {
336         vhost_user_cleanup(s->vhost_user);
337         g_free(s->vhost_user);
338         s->vhost_user = NULL;
339     }
340 }
341 
342 static void vhost_user_blk_instance_init(Object *obj)
343 {
344     VHostUserBlk *s = VHOST_USER_BLK(obj);
345 
346     device_add_bootindex_property(obj, &s->bootindex, "bootindex",
347                                   "/disk@0,0", DEVICE(obj), NULL);
348 }
349 
350 static const VMStateDescription vmstate_vhost_user_blk = {
351     .name = "vhost-user-blk",
352     .minimum_version_id = 1,
353     .version_id = 1,
354     .fields = (VMStateField[]) {
355         VMSTATE_VIRTIO_DEVICE,
356         VMSTATE_END_OF_LIST()
357     },
358 };
359 
360 static Property vhost_user_blk_properties[] = {
361     DEFINE_PROP_CHR("chardev", VHostUserBlk, chardev),
362     DEFINE_PROP_UINT16("num-queues", VHostUserBlk, num_queues, 1),
363     DEFINE_PROP_UINT32("queue-size", VHostUserBlk, queue_size, 128),
364     DEFINE_PROP_BIT("config-wce", VHostUserBlk, config_wce, 0, true),
365     DEFINE_PROP_END_OF_LIST(),
366 };
367 
368 static void vhost_user_blk_class_init(ObjectClass *klass, void *data)
369 {
370     DeviceClass *dc = DEVICE_CLASS(klass);
371     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
372 
373     dc->props = vhost_user_blk_properties;
374     dc->vmsd = &vmstate_vhost_user_blk;
375     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
376     vdc->realize = vhost_user_blk_device_realize;
377     vdc->unrealize = vhost_user_blk_device_unrealize;
378     vdc->get_config = vhost_user_blk_update_config;
379     vdc->set_config = vhost_user_blk_set_config;
380     vdc->get_features = vhost_user_blk_get_features;
381     vdc->set_status = vhost_user_blk_set_status;
382 }
383 
384 static const TypeInfo vhost_user_blk_info = {
385     .name = TYPE_VHOST_USER_BLK,
386     .parent = TYPE_VIRTIO_DEVICE,
387     .instance_size = sizeof(VHostUserBlk),
388     .instance_init = vhost_user_blk_instance_init,
389     .class_init = vhost_user_blk_class_init,
390 };
391 
392 static void virtio_register_types(void)
393 {
394     type_register_static(&vhost_user_blk_info);
395 }
396 
397 type_init(virtio_register_types)
398