virtio_config.h

Go to the documentation of this file.

#ifndef _LINUX_VIRTIO_CONFIG_H
#define _LINUX_VIRTIO_CONFIG_H

#include <linux/err.h>
#include <linux/bug.h>
#include <linux/virtio.h>
#include <uapi/linux/virtio_config.h>

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);
    const char *(*bus_name)(struct virtio_device *vdev);
    int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
};

/* 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);

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);
}

#define virtio_config_val(vdev, fbit, offset, v) \
    virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v))

#define virtio_config_val_len(vdev, fbit, offset, v, len) \
    virtio_config_buf((vdev), (fbit), (offset), (v), (len))

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;
}

static inline
const char *virtio_bus_name(struct virtio_device *vdev)
{
    if (!vdev->config->bus_name)
        return "virtio";
    return vdev->config->bus_name(vdev);
}

static inline
int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
{
    struct virtio_device *vdev = vq->vdev;
    if (vdev->config->set_vq_affinity)
        return vdev->config->set_vq_affinity(vq, cpu);
    return 0;
}


#endif /* _LINUX_VIRTIO_CONFIG_H */