> -----Original Message----- > From: Xen-devel [mailto:xen-devel-boun...@lists.xen.org] On Behalf Of > Julien Grall > Sent: 13 June 2016 11:51 > To: boris.ostrov...@oracle.com; David Vrabel; jgr...@suse.com; > sstabell...@kernel.org; konrad.w...@oracle.com > Cc: steve.cap...@arm.com; Andrew Cooper; linux-ker...@vger.kernel.org; > xen-devel@lists.xen.org; Julien Grall; jbeul...@suse.com > Subject: [Xen-devel] [PATCH] xen: grant-table: Check truncation when giving > access to a frame > > The version 1 of the grant-table protocol only supports frame encoded on > 32-bit. > > When the platform is supporting 48-bit physical address, the frame will > be encoded on 36-bit which will lead a truncation and give access to > the wrong frame. > > On ARM Xen will always allow the guest to use all the physical address, > although today the RAM is always located under 40-bits (see > xen/include/public/arch-arm.h). > > Add a truncation check in gnttab_update_entry_v1 to prevent the guest to > give access to the wrong frame. > > Signed-off-by: Julien Grall <julien.gr...@arm.com> > > --- > This is limiting us to a 44-bit address space whilst ARM can support > up to 48-bit today. This number of bit will increase to 52-bit in > upcoming processors [1]. > > It might be good to start thinking to extend the version 1 of the > protocol to use 64-bit frame number.
...or simply use version 2 of the protocol. Paul _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
