On Mon, Dec 01, 2014 at 12:07:07PM +0000, Peter Maydell wrote: > On 30 November 2014 at 16:43, Michael S. Tsirkin <m...@redhat.com> wrote: > > The result of this is host mapping leak. > > What effect does this have? Can this DOS host? > > I don't think we can DOS the host here. > > If Xen, we crash (but you can't use virtio-blk with Xen anyway) > Otherwise, if you managed to get address_space_map() to hand you > the bounce-buffer (by asking for dma to something other than RAM) > then we'll either hit an assertion or just end up never allowing > dma to/from non-RAM ever again for this guest. > The usual case would be that this was dma to/from ram, in > which case it's harmless if the virtio-backend never wrote to > the memory, and will fail to update dirty bitmaps for migration > etc if the backend did write. > > In any case I think that none of these outcomes are worse > than the "exit(1)" the current patch proposes. > > -- PMM
Fair enough. Pls disregard the patch then, and we'll fix it properly for 2.3 when we set ANY_LAYOUT.
