Re: [Ocf-linux-users] CIOCKEY & hifn7751driver

[David M. <Dav...@se...>]

Jivin John Gumb lays it down ...
> Hi Folks
> 
> Is there any reason why the hifn 7751 driver doesn't support the CIOCKEY
> operation to facilitate in diffie-hellman calculations (a^b mod m)?

Unless you have a particularly slow CPU the gains here are minimal.
>From experience most CPU's can crunch the numbers just as fast,  so the
benefit is in the CPU offload.  So you need to have other things to do
while waiting for the result from the crypto chip in order to see any gain.

Also,  the MOD_EXP acceleration is a very small part of the entire
key exchange process,  so even if you reduce it to zero time and zero
overhead,  it still isn't a huge gain overall :-(

> It seems there are some #defines for HIFN_VULCANDEV which appear to be
> related to using the private/public key stuff which the card supports
> from 'user mode' but I can't seem to find out much about this.

The HIFN_VULCANDEV stuff is not complete and not used in the current
source.

> Seems like the right way to expose this functionality is via CIOCKEY

I think the xelerance guys did some work here.  The current driver
doesn't support the newer hifn chips IIRC (ie., the ones that need the
hifn dev kit to build).  There may be a driver out there but I haven't
put in the effort to find it and pull the support back in to OCF.

You should be able to find something by following:

	http://www.xelerance.com/pr/20070205/

It would be nice to get the rest of this support back into OCF at some
point if there is anything still missing.

Both the safenet and ixp drivers do CRK_MOD_EXP on the appropriate HW
if you need a reference,

Cheers,
Davidm

-- 
David McCullough,  dav...@se...,   Ph:+61 734352815
Secure Computing - SnapGear  http://www.uCdot.org   http://www.snapgear.com