Re: [PATCH v3 01/23] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op (v10)

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

> > diff --git a/xen/include/public/sysctl.h b/xen/include/public/sysctl.h
> > index 96680eb..d549e7a 100644
> > --- a/xen/include/public/sysctl.h
> > +++ b/xen/include/public/sysctl.h
> > @@ -766,6 +766,160 @@ struct xen_sysctl_tmem_op {
> >  typedef struct xen_sysctl_tmem_op xen_sysctl_tmem_op_t;
> >  DEFINE_XEN_GUEST_HANDLE(xen_sysctl_tmem_op_t);
> >  
> > +/*
> > + * XEN_SYSCTL_XSPLICE_op
> > + *
> > + * Refer to the http://xenbits.xenproject.org/docs/unstable/misc/xsplice.html
> 
> I would refer to the file in the source tree, so docs/misc/xsplice.$FOO
> which is far less likely to change.

The initial patch had exactly that -  but Jan asked me to change it to the
URL. Shall I include both of them?

.. snip..
> > + * Retrieve an array of abbreviated status and names of payloads that are
> > + * loaded in the hypervisor.
> > + *
> > + * If the hypercall returns an positive number, it is the number (up to `nr`)
> > + * of the payloads returned, along with `nr` updated with the number of remaining
> > + * payloads, `version` updated (it may be the same across hypercalls. If it
> > + * varies the data is stale and further calls could fail). The `status`,
> > + * `name`, and `len`' are updated at their designed index value (`idx`) with
> > + * the returned value of data.
> > + *
> > + * If the hypercall returns E2BIG the `nr` is too big and should be
> > + * lowered.
> 
> What would cause this situation to occur?

If the hypervisor decided that the 'nr' is too big. It is hardcoded to an value - but
I don't think it makes sense to mention that in the header filer.
> 
> > + *
> > + * This operation can be preempted by the hypercall returning EAGAIN.
> > + * Retry.
> 
> Again, why is this necessary or useful?

Actually it is a lie. I've updated the design document but forgot to remove it here!

Thanks for the comments! Let me update the file..