#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. */ /* 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? */ MAYBE_BUILD_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 */