On 21/05/15 11:15, Jan Beulich wrote: > This is needed as stacks are going to become non-executable. Use > separate stub pages (shared among suitable CPUs on the same node) > instead. > > Stub areas (currently 128 bytes each) are being split into two parts - > a fixed usage one (the syscall ones) and dynamically usable space, > which will be used by subsequent changes to hold dynamically generated > code during instruction eumlation. > > While sharing physical pages among certain CPUs on the same node, for > now the virtual mappings get established in distinct pages for each > CPU. This isn't a strict requirement, but simplifies VA space > management for this initial implementation: Sharing VA space would > require additional tracking of which areas are currently in use. If > the VA and/or TLB overhead turned out to be a problem, such extra code > could easily be added. > > Signed-off-by: Jan Beulich <jbeul...@suse.com>
Reviewed-by: Andrew Cooper <andrew.coop...@citrix.com> It might be wise to have a BUILD_BUG_ON() which confirms that STUBS_PER_PAGE is a power of two, which is a requirement given the way it is used. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
