Re: [Xen-devel] [PATCH 06/11] xen/mmu: For 64-bit do not callxen_map_identity_early

[Ian Campbell]

On Mon, 2012-08-20 at 12:45 +0100, Stefano Stabellini wrote:
> On Fri, 17 Aug 2012, Konrad Rzeszutek Wilk wrote:
> > On Fri, Aug 17, 2012 at 06:41:23PM +0100, Stefano Stabellini wrote:
> > > On Thu, 16 Aug 2012, Konrad Rzeszutek Wilk wrote:
> > > > B/c we do not need it. During the startup the Xen provides
> > > > us with all the memory mapped that we need to function.
> > > 
> > > Shouldn't we check to make sure that is actually true (I am thinking at
> > > nr_pt_frames)?
> > 
> > I was looking at the source code (hypervisor) to figure it out and
> > that is certainly true.
> > 
> > 
> > > Or is it actually stated somewhere in the Xen headers?
> > 
> > Couldn't find it, but after looking so long at the source code
> > I didn't even bother looking for it.
> > 
> > Thought to be honest - I only looked at how the 64-bit pagetables
> > were set up, so I didn't dare to touch the 32-bit. Hence the #ifdef
> 
> I think that we need to involve some Xen maintainers and get this
> written down somewhere in the public headers, otherwise we have no
> guarantees that it is going to stay as it is in the next Xen versions.
> 
> Maybe we just need to add a couple of lines of comment to
> xen/include/public/xen.h.

The start of day memory layout for PV guests is written down in the
comment just before struct start_info at
http://xenbits.xen.org/docs/unstable/hypercall/include,public,xen.h.html#Struct_start_info

(I haven't read this thread to determine if what is documented matches
what you guys are talking about relying on)

Ian.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/