Re: [Xen-devel] [RFC PATCH 1/8]: PVH: Basic and preparatory changes

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Fri, 17 Aug 2012, Ian Campbell wrote:
> > > > diff --git a/include/xen/interface/xen.h
> > > > b/include/xen/interface/xen.h index 0801468..1d5bc36 100644
> > > > --- a/include/xen/interface/xen.h
> > > > +++ b/include/xen/interface/xen.h
> > > > @@ -493,6 +493,7 @@ struct dom0_vga_console_info {
> > > >  /* These flags are passed in the 'flags' field of start_info_t. */
> > > >  #define SIF_PRIVILEGED    (1<<0)  /* Is the domain privileged? */
> > > >  #define SIF_INITDOMAIN    (1<<1)  /* Is this the initial control
> > > > domain? */ +#define SIF_IS_PVINHVM    (1<<4)  /* Is it a PV running
> > > > in HVM container? */ #define SIF_PM_MASK       (0xFF<<8) /* reserve
> > > > 1 byte for xen-pm options */ 
> > > >  typedef uint64_t cpumap_t;
> > > 
> > > I would avoid adding SIF_IS_PVINHVM, an x86 specific concept, into a
> > > generic xen.h interface file. 
> 
> Is PVH actually more like a XENFEAT style thing?
> 
> Is there actually anywhere which wants to know specifically about PVH
> rather than some more specific property which a PVH domain happen to
> has?

That's exactly the point.


> > > > +/* xen_pv_domain check is necessary as start_info ptr is null in
> > > > HVM. Also,
> > > > + * note, xen PVH domain shares lot of HVM code */
> > > > +#define xen_pvh_domain()       (xen_pv_domain()
> > > > &&                     \
> > > > +                               (xen_start_info->flags &
> > > > SIF_IS_PVINHVM))
> > >  
> > > Also here.
> > 
> > Hmm.. I can move '#define xen_pvh_domain()' to x86 header, easy. But,
> > not sure how to define SIF_IS_PVINHVM then? I could put SIF_IS_RESVD in
> > include/xen/interface/xen.h, and then do 
> > #define SIF_IS_PVINHVM SIF_IS_RESVD in an x86 file.
> > 
> > What do you think about that?
> 
> Should PVH actually be a new value in the xen_domain_type enum?

I don't think we should have a xen_domain_type pvh at all.
If we really need it we should define it as a set of individual
properties:

#define xen_pvh_domain() (xen_pv_domain() && \
                          xen_feature(XENFEAT_auto_translated_physmap) && \
                          xen_have_vector_callback)

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