On Thu, Mar 5, 2020 at 8:38 AM Durrant, Paul <pdurr...@amazon.co.uk> wrote:
>
> > -----Original Message-----
> > From: Tamas K Lengyel <ta...@tklengyel.com>
> > Sent: 05 March 2020 15:10
> > To: pdurr...@amzn.com
> > Cc: Xen-devel <xen-devel@lists.xenproject.org>; Durrant, Paul 
> > <pdurr...@amazon.co.uk>; Jan Beulich
> > <jbeul...@suse.com>; Andrew Cooper <andrew.coop...@citrix.com>; Wei Liu 
> > <w...@xen.org>; Roger Pau Monné
> > <roger....@citrix.com>; George Dunlap <george.dun...@citrix.com>; Ian 
> > Jackson
> > <ian.jack...@eu.citrix.com>; Julien Grall <jul...@xen.org>; Konrad 
> > Rzeszutek Wilk
> > <konrad.w...@oracle.com>; Stefano Stabellini <sstabell...@kernel.org>; Tim 
> > Deegan <t...@xen.org>
> > Subject: RE: [EXTERNAL][PATCH v3 5/6] mm: add 'is_special_page' macro...
> >
> > CAUTION: This email originated from outside of the organization. Do not 
> > click links or open
> > attachments unless you can confirm the sender and know the content is safe.
> >
> >
> >
> > On Thu, Mar 5, 2020 at 5:45 AM <pdurr...@amzn.com> wrote:
> > >
> > > From: Paul Durrant <pdurr...@amazon.com>
> > >
> > > ... to cover xenheap and PGC_extra pages.
> > >
> > > PGC_extra pages are intended to hold data structures that are associated
> > > with a domain and my be mapped by that domain. They should not be treated
> > > as 'normal' guest pages (i.e. RAM or page tables). Hence, in many cases
> > > where code currently tests is_xen_heap_page() it should also check for
> > > the PGC_extra bit in 'count_info'.
> > >
> > > This patch therefore defines is_special_page() to cover both cases and
> > > converts tests if is_xen_heap_page() to is_special_page() where
> > > appropriate.
> >
> > In context of VM forking, are these pages only used by some type of PV
> > mechanism? If not, would we need to get them copied somehow or are
> > these setup during the regular createdomain routine? Can they be
> > copied on-demand, ie. do these pages pass a p2m_is_ram() check?
>
> PGC_extra domheap pages are intended as direct replacements for shared 
> xenheap pages and should be treated the same way. Thus they do not form part 
> of the migration stream. Their p2m type depends entirely on how they are 
> added to the p2m, as it is for any other page.

OK, thanks. For the mem_sharing bits:

Acked-by: Tamas K Lengyel <ta...@tklengyel.com>

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

Reply via email to