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
