Re: [PATCH 2/2] vfio: ccw: validate the count field of a ccw before pinning

Cornelia Huck
2017-10-16T09:14:20Z

On Wed, 11 Oct 2017 04:38:22 +0200
Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> wrote:

> If the count field of a ccw is zero, there is no need to
> try to pin page(s) for it. Let's check the count value
> before starting pinning operations.
>
> Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
> Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
> ---
> drivers/s390/cio/vfio_ccw_cp.c | 18 +++++++++++++++++-
> 1 file changed, 17 insertions(+), 1 deletion(-)

This sounds reasonable, and I could not spot anything in the
architecture that speaks against simply setting the IDA flag. Hopefully
there's nothing buried out of sight :)