text: /* SPDX-License-Identifier: GPL-2.0 */
  #include <linux/virtio_byteorder.h>
  #include <linux/virtio.h>
  #include <uapi/linux/virtio_config.h>
  
  /*
   * __virtio_test_bit - helper to test feature bits. For use by transports.
   *                     Devices should normally use virtio_has_feature,
   *                     which includes more checks.
   * @vdev: the device
   * @fbit: the feature bit
   */
  static inline bool __virtio_test_bit(const struct virtio_device *vdev,
  				     unsigned int fbit)
  {
  	return vdev->features & (1ULL << fbit);
  }
  
  /**
   * __virtio_set_bit - helper to set feature bits. For use by transports.
   * @vdev: the device
   * @fbit: the feature bit
   */
  static inline void __virtio_set_bit(struct virtio_device *vdev,
  				    unsigned int fbit)
  {
  	vdev->features |= (1ULL << fbit);
  }
  
  /**
   * __virtio_clear_bit - helper to clear feature bits. For use by transports.
   * @vdev: the device
   * @fbit: the feature bit
   */
  static inline void __virtio_clear_bit(struct virtio_device *vdev,
  				      unsigned int fbit)
  {
  	vdev->features &= ~(1ULL << fbit);
  }
  
  #define virtio_has_feature(dev, feature) \
  	(__virtio_test_bit((dev), feature))
  
  /**
   * virtio_has_iommu_quirk - determine whether this device has the iommu quirk
   * @vdev: the device
   */
  static inline bool virtio_has_iommu_quirk(const struct virtio_device *vdev)
  {
  	/*
  	 * Note the reverse polarity of the quirk feature (compared to most
  	 * other features), this is for compatibility with legacy systems.
  	 */
  	return !virtio_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
  }
  
  static inline bool virtio_is_little_endian(struct virtio_device *vdev)
  {
  	return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
  		virtio_legacy_is_little_endian();
  }
  
  /* Memory accessors */
  static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
  {
  	return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
  }
  
  static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
  {
  	return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
  }
  
  static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
  {
  	return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
  }
  
  static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
  {
  	return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
  }
  
  static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
  {
  	return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
  }
  
  static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
  {
  	return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
  }
  