Re: [PATCH 3/5] tools/vhost-user-i2c: Add backend driver

[Jie Deng]

On 2021/3/24 15:33, Viresh Kumar wrote:
> +
> +/* Definitions from virtio-i2c specifications */
> +#define VHOST_USER_I2C_MAX_QUEUES       1
> +
> +/* Status */
> +#define VIRTIO_I2C_MSG_OK               0
> +#define VIRTIO_I2C_MSG_ERR              1
> +
> +/* The bit 0 of the @virtio_i2c_out_hdr.@flags, used to group the requests */
> +#define VIRTIO_I2C_FLAGS_FAIL_NEXT      0x00000001
> +
> +/**
> + * struct virtio_i2c_out_hdr - the virtio I2C message OUT header
> + * @addr: the controlled device's address
> + * @padding: used to pad to full dword
> + * @flags: used for feature extensibility
> + */
> +struct virtio_i2c_out_hdr {
> +    uint16_t addr;
> +    uint16_t padding;
> +    uint32_t flags;
> +} __attribute__((packed));


__le16,  __le32 ?


> +
> +/**
> + * struct virtio_i2c_in_hdr - the virtio I2C message IN header
> + * @status: the processing result from the backend
> + */
> +struct virtio_i2c_in_hdr {
> +    uint8_t status;
> +} __attribute__((packed));
> +


I understand these definitions can be removed once the frontend driver 
is merged by the Linux ?


> +/* vhost-user-i2c definitions */
> +
> +#ifndef container_of
> +#define container_of(ptr, type, member) ({                      \
> +        const typeof(((type *) 0)->member) *__mptr = (ptr);     \
> +        (type *) ((char *) __mptr - offsetof(type, member));})
> +#endif


This seems to be a general interface.  I see there is a definition in 
qemu/compiler.h.

Can we reuse it ?