Re: [PATCH v2 03/24] virtio: allow __virtioXX, __leXX in config space

[Jason Wang]

On 2020/8/5 下午7:45, Michael S. Tsirkin wrote:
> > >    #define virtio_cread(vdev, structname, member, ptr)			\
> > >    	do {								\
> > >    		might_sleep();						\
> > >    		/* Must match the member's type, and be integer */	\
> > > -		if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
> > > +		if (!__virtio_typecheck(structname, member, *(ptr)))	\
> > >    			(*ptr) = 1;					\
> > A silly question,  compare to using set()/get() directly, what's the value
> > of the accessors macro here?
> >
> > Thanks
> get/set don't convert to the native endian, I guess that's why
> drivers use cread/cwrite. It is also nice that there's type
> safety, checking the correct integer width is used.


Yes, but this is simply because a macro is used here, how about just 
doing things similar like virtio_cread_bytes():

static inline void virtio_cread(struct virtio_device *vdev,
                      unsigned int offset,
                      void *buf, size_t len)


And do the endian conversion inside?

Thanks


>