Am 14.06.2016 um 23:30 hat Eric Blake geschrieben: > Sector-based limits are awkward to think about; in our on-going > quest to move to byte-based interfaces, convert max_transfer_length > and opt_transfer_length. Rename them (dropping the _length suffix) > so that the compiler will help us catch the change in semantics > across any rebased code, and improve the documentation. Use unsigned > values, so that we don't have to worry about negative values and > so that bit-twiddling is easier; however, we are still constrained > by 2^31 of signed int in most APIs. > > Signed-off-by: Eric Blake <ebl...@redhat.com>
> @@ -1738,8 +1742,8 @@ static void iscsi_refresh_limits(BlockDriverState *bs, > Error **errp) > } else { > bs->bl.pwrite_zeroes_alignment = iscsilun->block_size; > } > - bs->bl.opt_transfer_length = > - sector_limits_lun2qemu(iscsilun->bl.opt_xfer_len, iscsilun); > + assert(iscsilun->bl.opt_xfer_len < INT_MAX / iscsilun->block_size); > + bs->bl.opt_transfer = iscsilun->bl.opt_xfer_len * iscsilun->block_size; > } iscsilun->bl.opt_xfer_len comes directly from libiscsi, and presumably from the iscsi server, without being checked or sanitised. I don't think we can assert a specific range of values for it but must assume that it can be any uint32_t. We can return an error for a device with a value that we don't like (even though using the maximum might be just fine), but crashing qemu is not an option. > diff --git a/block/raw-posix.c b/block/raw-posix.c > index aacf132..f2bea85 100644 > --- a/block/raw-posix.c > +++ b/block/raw-posix.c > @@ -752,7 +752,8 @@ static void raw_refresh_limits(BlockDriverState *bs, > Error **errp) > if (S_ISBLK(st.st_mode)) { > int ret = hdev_get_max_transfer_length(s->fd); > if (ret >= 0) { > - bs->bl.max_transfer_length = ret; > + assert(ret <= BDRV_REQUEST_MAX_SECTORS); > + bs->bl.max_transfer = ret << BDRV_SECTOR_BITS; > } > } > } Same thing here. Kevin