1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_VIRTIO_H
3 #define _LINUX_VIRTIO_H
4 /* Everything a virtio driver needs to work with any particular virtio
5 * implementation. */
6 #include <linux/types.h>
7 #include <linux/scatterlist.h>
8 #include <linux/spinlock.h>
9 #include <linux/device.h>
10 #include <linux/mod_devicetable.h>
11 #include <linux/gfp.h>
12 #include <linux/vringh.h>
13
14 /**
15 * virtqueue - a queue to register buffers for sending or receiving.
16 * @list: the chain of virtqueues for this device
17 * @callback: the function to call when buffers are consumed (can be NULL).
18 * @name: the name of this virtqueue (mainly for debugging)
19 * @vdev: the virtio device this queue was created for.
20 * @priv: a pointer for the virtqueue implementation to use.
21 * @index: the zero-based ordinal number for this queue.
22 * @num_free: number of elements we expect to be able to fit.
23 *
24 * A note on @num_free: with indirect buffers, each buffer needs one
25 * element in the queue, otherwise a buffer will need one element per
26 * sg element.
27 */
28 struct virtqueue {
29 struct list_head list;
30 void (*callback)(struct virtqueue *vq);
31 const char *name;
32 struct virtio_device *vdev;
33 unsigned int index;
34 unsigned int num_free;
35 void *priv;
36 };
37
38 int virtqueue_add_outbuf(struct virtqueue *vq,
39 struct scatterlist sg[], unsigned int num,
40 void *data,
41 gfp_t gfp);
42
43 int virtqueue_add_inbuf(struct virtqueue *vq,
44 struct scatterlist sg[], unsigned int num,
45 void *data,
46 gfp_t gfp);
47
48 int virtqueue_add_inbuf_ctx(struct virtqueue *vq,
49 struct scatterlist sg[], unsigned int num,
50 void *data,
51 void *ctx,
52 gfp_t gfp);
53
54 int virtqueue_add_sgs(struct virtqueue *vq,
55 struct scatterlist *sgs[],
56 unsigned int out_sgs,
57 unsigned int in_sgs,
58 void *data,
59 gfp_t gfp);
60
61 bool virtqueue_kick(struct virtqueue *vq);
62
63 bool virtqueue_kick_prepare(struct virtqueue *vq);
64
65 bool virtqueue_notify(struct virtqueue *vq);
66
67 void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
68
69 void *virtqueue_get_buf_ctx(struct virtqueue *vq, unsigned int *len,
70 void **ctx);
71
72 void virtqueue_disable_cb(struct virtqueue *vq);
73
74 bool virtqueue_enable_cb(struct virtqueue *vq);
75
76 unsigned virtqueue_enable_cb_prepare(struct virtqueue *vq);
77
78 bool virtqueue_poll(struct virtqueue *vq, unsigned);
79
80 bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
81
82 void *virtqueue_detach_unused_buf(struct virtqueue *vq);
83
84 unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
85
86 bool virtqueue_is_broken(struct virtqueue *vq);
87
88 const struct vring *virtqueue_get_vring(struct virtqueue *vq);
89 dma_addr_t virtqueue_get_desc_addr(struct virtqueue *vq);
90 dma_addr_t virtqueue_get_avail_addr(struct virtqueue *vq);
91 dma_addr_t virtqueue_get_used_addr(struct virtqueue *vq);
92
93 /*
94 * Legacy accessors -- in almost all cases, these are the wrong functions
95 * to use.
96 */
virtqueue_get_desc(struct virtqueue * vq)97 static inline void *virtqueue_get_desc(struct virtqueue *vq)
98 {
99 return virtqueue_get_vring(vq)->desc;
100 }
virtqueue_get_avail(struct virtqueue * vq)101 static inline void *virtqueue_get_avail(struct virtqueue *vq)
102 {
103 return virtqueue_get_vring(vq)->avail;
104 }
virtqueue_get_used(struct virtqueue * vq)105 static inline void *virtqueue_get_used(struct virtqueue *vq)
106 {
107 return virtqueue_get_vring(vq)->used;
108 }
109
110 /**
111 * virtio_device - representation of a device using virtio
112 * @index: unique position on the virtio bus
113 * @failed: saved value for VIRTIO_CONFIG_S_FAILED bit (for restore)
114 * @config_enabled: configuration change reporting enabled
115 * @config_change_pending: configuration change reported while disabled
116 * @config_lock: protects configuration change reporting
117 * @dev: underlying device.
118 * @id: the device type identification (used to match it with a driver).
119 * @config: the configuration ops for this device.
120 * @vringh_config: configuration ops for host vrings.
121 * @vqs: the list of virtqueues for this device.
122 * @features: the features supported by both driver and device.
123 * @priv: private pointer for the driver's use.
124 */
125 struct virtio_device {
126 int index;
127 bool failed;
128 bool config_enabled;
129 bool config_change_pending;
130 spinlock_t config_lock;
131 struct device dev;
132 struct virtio_device_id id;
133 const struct virtio_config_ops *config;
134 const struct vringh_config_ops *vringh_config;
135 struct list_head vqs;
136 u64 features;
137 void *priv;
138 };
139
dev_to_virtio(struct device * _dev)140 static inline struct virtio_device *dev_to_virtio(struct device *_dev)
141 {
142 return container_of(_dev, struct virtio_device, dev);
143 }
144
145 void virtio_add_status(struct virtio_device *dev, unsigned int status);
146 int register_virtio_device(struct virtio_device *dev);
147 void unregister_virtio_device(struct virtio_device *dev);
148
149 void virtio_break_device(struct virtio_device *dev);
150
151 void virtio_config_changed(struct virtio_device *dev);
152 void virtio_config_disable(struct virtio_device *dev);
153 void virtio_config_enable(struct virtio_device *dev);
154 int virtio_finalize_features(struct virtio_device *dev);
155 #ifdef CONFIG_PM_SLEEP
156 int virtio_device_freeze(struct virtio_device *dev);
157 int virtio_device_restore(struct virtio_device *dev);
158 #endif
159
160 #define virtio_device_for_each_vq(vdev, vq) \
161 list_for_each_entry(vq, &vdev->vqs, list)
162
163 /**
164 * virtio_driver - operations for a virtio I/O driver
165 * @driver: underlying device driver (populate name and owner).
166 * @id_table: the ids serviced by this driver.
167 * @feature_table: an array of feature numbers supported by this driver.
168 * @feature_table_size: number of entries in the feature table array.
169 * @feature_table_legacy: same as feature_table but when working in legacy mode.
170 * @feature_table_size_legacy: number of entries in feature table legacy array.
171 * @probe: the function to call when a device is found. Returns 0 or -errno.
172 * @scan: optional function to call after successful probe; intended
173 * for virtio-scsi to invoke a scan.
174 * @remove: the function to call when a device is removed.
175 * @config_changed: optional function to call when the device configuration
176 * changes; may be called in interrupt context.
177 * @freeze: optional function to call during suspend/hibernation.
178 * @restore: optional function to call on resume.
179 */
180 struct virtio_driver {
181 struct device_driver driver;
182 const struct virtio_device_id *id_table;
183 const unsigned int *feature_table;
184 unsigned int feature_table_size;
185 const unsigned int *feature_table_legacy;
186 unsigned int feature_table_size_legacy;
187 int (*validate)(struct virtio_device *dev);
188 int (*probe)(struct virtio_device *dev);
189 void (*scan)(struct virtio_device *dev);
190 void (*remove)(struct virtio_device *dev);
191 void (*config_changed)(struct virtio_device *dev);
192 #ifdef CONFIG_PM
193 int (*freeze)(struct virtio_device *dev);
194 int (*restore)(struct virtio_device *dev);
195 #endif
196 };
197
drv_to_virtio(struct device_driver * drv)198 static inline struct virtio_driver *drv_to_virtio(struct device_driver *drv)
199 {
200 return container_of(drv, struct virtio_driver, driver);
201 }
202
203 int register_virtio_driver(struct virtio_driver *drv);
204 void unregister_virtio_driver(struct virtio_driver *drv);
205
206 /* module_virtio_driver() - Helper macro for drivers that don't do
207 * anything special in module init/exit. This eliminates a lot of
208 * boilerplate. Each module may only use this macro once, and
209 * calling it replaces module_init() and module_exit()
210 */
211 #define module_virtio_driver(__virtio_driver) \
212 module_driver(__virtio_driver, register_virtio_driver, \
213 unregister_virtio_driver)
214 #endif /* _LINUX_VIRTIO_H */
215
