Re: [PATCH] Paging and memory sharing for HVM guests

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

On Thu, Dec 17, 2009 at 04:59:58PM +0000, Jan Beulich wrote:
> >>> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 17.12.09 17:38 >>>
> >1). The  "*mfnp |= 0x80000000U;" and "*mfnp |= 0xf0000000U;" should
> >    use a #define. Maybe copy over the #defines from the xen tree ?
> 
> Did you find any defines in the tools sources for that? The only place I
> found this condition being checked at all was in xc_map_foreign_pages(),
> where it used hard-coded values. Or are you referring to the
> XEN_DOMCTL_PFINFO_* values? I'd say they're being mis-used when

Yes, those are the ones that I've gotten it from. Granted, as you said
they aren't wide enough for this. And it does look a bit unhealthy
to be writting those values in. I was thinking that that mmu.c should
probably have some code for this too to check if those MFNs
are no good.

> applied to the mfn array used by mmap-batch (including apparent
> pre-existing uses).

I am not that familiar with the grant driver to make a good judgment
on that. But I do think that upstream Linux folks would gag on this code
as "hacky".