Re: [Xen-devel] [PATCH RFC v1 21/74] x86/entry: Early PVH boot code

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Tue, Jan 09, 2018 at 09:41:51AM -0700, Jan Beulich wrote:
> >>> On 09.01.18 at 16:45, <wei.liu2@xxxxxxxxxx> wrote:
> > On Fri, Jan 05, 2018 at 06:32:56AM -0700, Jan Beulich wrote:
> >> > +    pvh_mbi.mods_count = pvh_info->nr_modules;
> >> > +    pvh_mbi.mods_addr = __pa(pvh_mbi_mods);
> >> > +
> >> > +    mod = pvh_mbi_mods;
> >> > +    entry = __va(pvh_info->modlist_paddr);
> >> 
> >> How come __va() already works at this point in time? And what about
> >> this address being beyond 4Gb?
> >> 
> > 
> > The original code uses __va at the beginning of __start_xen so this is
> > no more erroneous than what we originally have.
> 
> Well, I was assuming that these uses of __va() here are the
> reason why you need to extend the initial mapping in another
> patch. The original ones early in __start_xen() all deal with the
> MBI which we've relocated to a place where __va() can be used.

I see -- I thought everything was relocated automatically, which in
hindsight looks very stupid. That's probably why Andrew wrote that patch
to extend the mapping. We can certainly relocate pvh info as well, but
then that would delay the work.  We can add that as a blocker for the
proper solution later.

Wei.

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