On Mon, 3 Aug 2020 16:58:46 -0400 "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote: > Currently all config space fields are of the type __uXX. > This confuses people and some drivers (notably vdpa) > access them using CPU endian-ness - which only > works well for legacy or LE platforms. > > Update virtio_cread/virtio_cwrite macros to allow __virtioXX > and __leXX field types. Follow-up patches will convert > config space to use these types. > > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > --- > include/linux/virtio_config.h | 50 +++++++++++++++++++++++++++++++++-- > 1 file changed, 48 insertions(+), 2 deletions(-) (...) > @@ -287,12 +288,57 @@ static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val) > return __cpu_to_virtio64(virtio_is_little_endian(vdev), val); > } > > +/* > + * Only the checker differentiates between __virtioXX and __uXX types. But we > + * try to share as much code as we can with the regular GCC build. > + */ > +#if !defined(CONFIG_CC_IS_GCC) && !defined(__CHECKER__) > + > +/* Not a checker - we can keep things simple */ > +#define __virtio_native_typeof(x) typeof(x) > + > +#else > + > +/* > + * We build this out of a couple of helper macros in a vain attempt to > + * help you keep your lunch down while reading it. > + */ It might help with the lunch, but it still gives a slight queasiness. No ideas for a better version, though. > +#define __virtio_pick_value(x, type, then, otherwise) \ > + __builtin_choose_expr(__same_type(x, type), then, otherwise) > + > +#define __virtio_pick_type(x, type, then, otherwise) \ > + __virtio_pick_value(x, type, (then)0, otherwise) > + > +#define __virtio_pick_endian(x, x16, x32, x64, otherwise) \ > + __virtio_pick_type(x, x16, __u16, \ > + __virtio_pick_type(x, x32, __u32, \ > + __virtio_pick_type(x, x64, __u64, \ > + otherwise))) > + > +#define __virtio_native_typeof(x) typeof( \ > + __virtio_pick_type(x, __u8, __u8, \ > + __virtio_pick_endian(x, __virtio16, __virtio32, __virtio64, \ > + __virtio_pick_endian(x, __le16, __le32, __le64, \ > + __virtio_pick_endian(x, __u16, __u32, __u64, \ > + /* No other type allowed */ \ > + (void)0))))) > + > +#endif > + > +#define __virtio_native_type(structname, member) \ > + __virtio_native_typeof(((structname*)0)->member) > + > +#define __virtio_typecheck(structname, member, val) \ > + /* Must match the member's type, and be integer */ \ > + typecheck(__virtio_native_type(structname, member), (val)) > + > + Acked-by: Cornelia Huck <cohuck@xxxxxxxxxx> _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
