> From: Jan Beulich [mailto:jbeul...@suse.com] > Sent: Wednesday, December 16, 2015 3:58 PM > > ... since we don't need its virtual address anywhere (it's a > placeholder page only after all). For this wo work (and possibly be > done elsewhere too) share_xen_page_with_guest() needs to mark pages > handed to it as Xen heap ones. > > To be on the safe side, also explicitly clear the page (not having done > so was okay due to the XSA-100 fix, but is still a latent bug since we > don't formally guarantee allocations to come out zeroed, and in fact > this property may disappear again as soon as the asynchronous runtime > scrubbing patches arrive).
Do you mean that asynchronous scrubbing may scrub page after they are re-allocated? It's unrelated but a bit risky to me. > > Signed-off-by: Jan Beulich <jbeul...@suse.com> > --- > Alternatives might be to use a > - global (or perhaps per-node) page across VMs (on the basis that VMs > shouldn't be writing into that page anyway) > - fake MFN pointing into nowhere (would need to ensure no side effects > can occur, like PCIe errors or NMIs) one page per VM should be fine. We don't need go that route. the patch overall looks OK to me: Acked-by: Kevin Tian <kevin.t...@intel.com> Thanks Kevin _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
