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Diffstat (limited to 'include/linux/virtio_config.h')
| -rw-r--r-- | include/linux/virtio_config.h | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h new file mode 100644 index 00000000..39c88c5a --- /dev/null +++ b/include/linux/virtio_config.h @@ -0,0 +1,183 @@ +#ifndef _LINUX_VIRTIO_CONFIG_H +#define _LINUX_VIRTIO_CONFIG_H +/* This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so + * anyone can use the definitions to implement compatible drivers/servers. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of IBM nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. */ + +/* Virtio devices use a standardized configuration space to define their + * features and pass configuration information, but each implementation can + * store and access that space differently. */ +#include <linux/types.h> + +/* Status byte for guest to report progress, and synchronize features. */ +/* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */ +#define VIRTIO_CONFIG_S_ACKNOWLEDGE 1 +/* We have found a driver for the device. */ +#define VIRTIO_CONFIG_S_DRIVER 2 +/* Driver has used its parts of the config, and is happy */ +#define VIRTIO_CONFIG_S_DRIVER_OK 4 +/* We've given up on this device. */ +#define VIRTIO_CONFIG_S_FAILED 0x80 + +/* Some virtio feature bits (currently bits 28 through 31) are reserved for the + * transport being used (eg. virtio_ring), the rest are per-device feature + * bits. */ +#define VIRTIO_TRANSPORT_F_START 28 +#define VIRTIO_TRANSPORT_F_END 32 + +/* Do we get callbacks when the ring is completely used, even if we've + * suppressed them? */ +#define VIRTIO_F_NOTIFY_ON_EMPTY 24 + +#ifdef __KERNEL__ +#include <linux/err.h> +#include <linux/virtio.h> + +/** + * virtio_config_ops - operations for configuring a virtio device + * @get: read the value of a configuration field + * vdev: the virtio_device + * offset: the offset of the configuration field + * buf: the buffer to write the field value into. + * len: the length of the buffer + * @set: write the value of a configuration field + * vdev: the virtio_device + * offset: the offset of the configuration field + * buf: the buffer to read the field value from. + * len: the length of the buffer + * @get_status: read the status byte + * vdev: the virtio_device + * Returns the status byte + * @set_status: write the status byte + * vdev: the virtio_device + * status: the new status byte + * @request_vqs: request the specified number of virtqueues + * vdev: the virtio_device + * max_vqs: the max number of virtqueues we want + * If supplied, must call before any virtqueues are instantiated. + * To modify the max number of virtqueues after request_vqs has been + * called, call free_vqs and then request_vqs with a new value. + * @free_vqs: cleanup resources allocated by request_vqs + * vdev: the virtio_device + * If supplied, must call after all virtqueues have been deleted. + * @reset: reset the device + * vdev: the virtio device + * After this, status and feature negotiation must be done again + * @find_vqs: find virtqueues and instantiate them. + * vdev: the virtio_device + * nvqs: the number of virtqueues to find + * vqs: on success, includes new virtqueues + * callbacks: array of callbacks, for each virtqueue + * names: array of virtqueue names (mainly for debugging) + * Returns 0 on success or error status + * @del_vqs: free virtqueues found by find_vqs(). + * @get_features: get the array of feature bits for this device. + * vdev: the virtio_device + * Returns the first 32 feature bits (all we currently need). + * @finalize_features: confirm what device features we'll be using. + * vdev: the virtio_device + * This gives the final feature bits for the device: it can change + * the dev->feature bits if it wants. + */ +typedef void vq_callback_t(struct virtqueue *); +struct virtio_config_ops { + void (*get)(struct virtio_device *vdev, unsigned offset, + void *buf, unsigned len); + void (*set)(struct virtio_device *vdev, unsigned offset, + const void *buf, unsigned len); + u8 (*get_status)(struct virtio_device *vdev); + void (*set_status)(struct virtio_device *vdev, u8 status); + void (*reset)(struct virtio_device *vdev); + int (*find_vqs)(struct virtio_device *, unsigned nvqs, + struct virtqueue *vqs[], + vq_callback_t *callbacks[], + const char *names[]); + void (*del_vqs)(struct virtio_device *); + u32 (*get_features)(struct virtio_device *vdev); + void (*finalize_features)(struct virtio_device *vdev); +}; + +/* If driver didn't advertise the feature, it will never appear. */ +void virtio_check_driver_offered_feature(const struct virtio_device *vdev, + unsigned int fbit); + +/** + * virtio_has_feature - helper to determine if this device has this feature. + * @vdev: the device + * @fbit: the feature bit + */ +static inline bool virtio_has_feature(const struct virtio_device *vdev, + unsigned int fbit) +{ + /* Did you forget to fix assumptions on max features? */ + if (__builtin_constant_p(fbit)) + BUILD_BUG_ON(fbit >= 32); + else + BUG_ON(fbit >= 32); + + if (fbit < VIRTIO_TRANSPORT_F_START) + virtio_check_driver_offered_feature(vdev, fbit); + + return test_bit(fbit, vdev->features); +} + +/** + * virtio_config_val - look for a feature and get a virtio config entry. + * @vdev: the virtio device + * @fbit: the feature bit + * @offset: the type to search for. + * @val: a pointer to the value to fill in. + * + * The return value is -ENOENT if the feature doesn't exist. Otherwise + * the config value is copied into whatever is pointed to by v. */ +#define virtio_config_val(vdev, fbit, offset, v) \ + virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v)) + +static inline int virtio_config_buf(struct virtio_device *vdev, + unsigned int fbit, + unsigned int offset, + void *buf, unsigned len) +{ + if (!virtio_has_feature(vdev, fbit)) + return -ENOENT; + + vdev->config->get(vdev, offset, buf, len); + return 0; +} + +static inline +struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev, + vq_callback_t *c, const char *n) +{ + vq_callback_t *callbacks[] = { c }; + const char *names[] = { n }; + struct virtqueue *vq; + int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names); + if (err < 0) + return ERR_PTR(err); + return vq; +} +#endif /* __KERNEL__ */ +#endif /* _LINUX_VIRTIO_CONFIG_H */ |