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1 #ifndef _LINUX_VIRTIO_CONFIG_H
2 #define _LINUX_VIRTIO_CONFIG_H
3 /* This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
4 * anyone can use the definitions to implement compatible drivers/servers.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of IBM nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 /* Virtio devices use a standardized configuration space to define their
30 * features and pass configuration information, but each implementation can
31 * store and access that space differently. */
32 #include <linux/types.h>
34 /* Status byte for guest to report progress, and synchronize features. */
35 /* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */
36 #define VIRTIO_CONFIG_S_ACKNOWLEDGE 1
37 /* We have found a driver for the device. */
38 #define VIRTIO_CONFIG_S_DRIVER 2
39 /* Driver has used its parts of the config, and is happy */
40 #define VIRTIO_CONFIG_S_DRIVER_OK 4
41 /* We've given up on this device. */
42 #define VIRTIO_CONFIG_S_FAILED 0x80
44 /* Some virtio feature bits (currently bits 28 through 31) are reserved for the
45 * transport being used (eg. virtio_ring), the rest are per-device feature
47 #define VIRTIO_TRANSPORT_F_START 28
48 #define VIRTIO_TRANSPORT_F_END 32
50 /* Do we get callbacks when the ring is completely used, even if we've
52 #define VIRTIO_F_NOTIFY_ON_EMPTY 24
55 #include <linux/err.h>
56 #include <linux/bug.h>
57 #include <linux/virtio.h>
60 * virtio_config_ops - operations for configuring a virtio device
61 * @get: read the value of a configuration field
62 * vdev: the virtio_device
63 * offset: the offset of the configuration field
64 * buf: the buffer to write the field value into.
65 * len: the length of the buffer
66 * @set: write the value of a configuration field
67 * vdev: the virtio_device
68 * offset: the offset of the configuration field
69 * buf: the buffer to read the field value from.
70 * len: the length of the buffer
71 * @get_status: read the status byte
72 * vdev: the virtio_device
73 * Returns the status byte
74 * @set_status: write the status byte
75 * vdev: the virtio_device
76 * status: the new status byte
77 * @reset: reset the device
78 * vdev: the virtio device
79 * After this, status and feature negotiation must be done again
80 * Device must not be reset from its vq/config callbacks, or in
81 * parallel with being added/removed.
82 * @find_vqs: find virtqueues and instantiate them.
83 * vdev: the virtio_device
84 * nvqs: the number of virtqueues to find
85 * vqs: on success, includes new virtqueues
86 * callbacks: array of callbacks, for each virtqueue
87 * include a NULL entry for vqs that do not need a callback
88 * names: array of virtqueue names (mainly for debugging)
89 * include a NULL entry for vqs unused by driver
90 * Returns 0 on success or error status
91 * @del_vqs: free virtqueues found by find_vqs().
92 * @get_features: get the array of feature bits for this device.
93 * vdev: the virtio_device
94 * Returns the first 32 feature bits (all we currently need).
95 * @finalize_features: confirm what device features we'll be using.
96 * vdev: the virtio_device
97 * This gives the final feature bits for the device: it can change
98 * the dev->feature bits if it wants.
99 * @bus_name: return the bus name associated with the device
100 * vdev: the virtio_device
101 * This returns a pointer to the bus name a la pci_name from which
102 * the caller can then copy.
103 * @set_vq_affinity: set the affinity for a virtqueue.
105 typedef void vq_callback_t(struct virtqueue
*);
106 struct virtio_config_ops
{
107 void (*get
)(struct virtio_device
*vdev
, unsigned offset
,
108 void *buf
, unsigned len
);
109 void (*set
)(struct virtio_device
*vdev
, unsigned offset
,
110 const void *buf
, unsigned len
);
111 u8 (*get_status
)(struct virtio_device
*vdev
);
112 void (*set_status
)(struct virtio_device
*vdev
, u8 status
);
113 void (*reset
)(struct virtio_device
*vdev
);
114 int (*find_vqs
)(struct virtio_device
*, unsigned nvqs
,
115 struct virtqueue
*vqs
[],
116 vq_callback_t
*callbacks
[],
117 const char *names
[]);
118 void (*del_vqs
)(struct virtio_device
*);
119 u32 (*get_features
)(struct virtio_device
*vdev
);
120 void (*finalize_features
)(struct virtio_device
*vdev
);
121 const char *(*bus_name
)(struct virtio_device
*vdev
);
122 int (*set_vq_affinity
)(struct virtqueue
*vq
, int cpu
);
125 /* If driver didn't advertise the feature, it will never appear. */
126 void virtio_check_driver_offered_feature(const struct virtio_device
*vdev
,
130 * virtio_has_feature - helper to determine if this device has this feature.
132 * @fbit: the feature bit
134 static inline bool virtio_has_feature(const struct virtio_device
*vdev
,
137 /* Did you forget to fix assumptions on max features? */
138 if (__builtin_constant_p(fbit
))
139 BUILD_BUG_ON(fbit
>= 32);
143 if (fbit
< VIRTIO_TRANSPORT_F_START
)
144 virtio_check_driver_offered_feature(vdev
, fbit
);
146 return test_bit(fbit
, vdev
->features
);
150 * virtio_config_val - look for a feature and get a virtio config entry.
151 * @vdev: the virtio device
152 * @fbit: the feature bit
153 * @offset: the type to search for.
154 * @v: a pointer to the value to fill in.
156 * The return value is -ENOENT if the feature doesn't exist. Otherwise
157 * the config value is copied into whatever is pointed to by v. */
158 #define virtio_config_val(vdev, fbit, offset, v) \
159 virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v))
161 #define virtio_config_val_len(vdev, fbit, offset, v, len) \
162 virtio_config_buf((vdev), (fbit), (offset), (v), (len))
164 static inline int virtio_config_buf(struct virtio_device
*vdev
,
167 void *buf
, unsigned len
)
169 if (!virtio_has_feature(vdev
, fbit
))
172 vdev
->config
->get(vdev
, offset
, buf
, len
);
177 struct virtqueue
*virtio_find_single_vq(struct virtio_device
*vdev
,
178 vq_callback_t
*c
, const char *n
)
180 vq_callback_t
*callbacks
[] = { c
};
181 const char *names
[] = { n
};
182 struct virtqueue
*vq
;
183 int err
= vdev
->config
->find_vqs(vdev
, 1, &vq
, callbacks
, names
);
190 const char *virtio_bus_name(struct virtio_device
*vdev
)
192 if (!vdev
->config
->bus_name
)
194 return vdev
->config
->bus_name(vdev
);
198 * virtqueue_set_affinity - setting affinity for a virtqueue
202 * Pay attention the function are best-effort: the affinity hint may not be set
203 * due to config support, irq type and sharing.
207 int virtqueue_set_affinity(struct virtqueue
*vq
, int cpu
)
209 struct virtio_device
*vdev
= vq
->vdev
;
210 if (vdev
->config
->set_vq_affinity
)
211 return vdev
->config
->set_vq_affinity(vq
, cpu
);
216 #endif /* __KERNEL__ */
217 #endif /* _LINUX_VIRTIO_CONFIG_H */