Re: Question on mlx5 PMD txq memory registration

On Sun, Jul 23, 2017 at 12:03:41PM +0300, Sagi Grimberg wrote:

quoted

quoted

I don't understand the security argument. Its completely private to the
driver. anything under librte is equivalent to an OS wrt networking, so I fail to
see what is the security feature your talking about.

You are correct that as a root you are able to do whatever you want on the server.
The security I refer to is to protect against badly written code.

The fact the PMD only registers the mempools, and use the device engine to translate the VA, provide some protection.
For example, one DPDK process will not be able to access the memory of other DPDK process *by mistake*.

Well, this is a fair argument, but without a *complete* solution for all
of dpdk peripherals, it has very little merit (if at all). A badly
written code can just as easily crash a server by passing a mbuf to
a crypto device or another network device that co-exists with mlx5.

So, while I understand the argument, I think its value is not worth the
hassle that mlx5_pmd needs to take to achieve it. Did this come from a
real requirement (from a real implementation)?

Would using VFIO (and the IOMMU) not allow us to provide an equivalent
level of security to what is provided by the current scheme? From what I
see on-list there are a few folks already looking into that area, and
taking advantage of the IOMMU should improve security of all devices in
DPDK.

/Bruce