Re: [Xen-devel] [PATCH 1/7] xen: import new ring macros in ring.h

[Julien Grall]

Hi Stefano,

On 08/03/17 00:12, Stefano Stabellini wrote:
> On Tue, 7 Mar 2017, Julien Grall wrote:
> > Hi Stefano,
> >
> > On 03/06/2017 08:01 PM, Stefano Stabellini wrote:
> > > Sync the ring.h file with upstream Xen, to introduce the new ring macros.
> > > They will be used by the Xen transport for 9pfs.
> > >
> > > Signed-off-by: Stefano Stabellini <stefano@xxxxxxxxxxx>
> > > CC: konrad.wilk@xxxxxxxxxx
> > > CC: boris.ostrovsky@xxxxxxxxxx
> > > CC: jgross@xxxxxxxx
> > >
> > > ---
> > > NB: The new macros have not been committed to Xen yet. Do not apply this
> > > patch until they do.
> > > ---
> > > ---
> > >  include/xen/interface/io/ring.h | 131
> > > ++++++++++++++++++++++++++++++++++++++++
> > >  1 file changed, 131 insertions(+)
> > >
> > > diff --git a/include/xen/interface/io/ring.h
> > > b/include/xen/interface/io/ring.h
> > > index 21f4fbd..e16aa92 100644
> > > --- a/include/xen/interface/io/ring.h
> > > +++ b/include/xen/interface/io/ring.h
> >
> > [...]
> >
> > > +#define XEN_FLEX_RING_SIZE(order)
> > > \
> > > +    (1UL << (order + PAGE_SHIFT - 1))
> >
> > This will need to be XEN_PAGE_SHIFT in order to works with 64K kernel.
>
> Good point! I had it right at the beginning but I lost the change in one
> of the updates from xen.git.

It is probably worth to consider introducing XEN_PAGE_SIZE in the 
hypervisor code because we are likely to miss the change when the 
headers will be re-sync in the future.

Cheers,

--
Julien Grall