Re: Crypto Update for 2.6.38

David Miller
2011-01-06T22:33:07Z

From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Fri, 7 Jan 2011 09:30:42 +1100

> On Thu, Jan 06, 2011 at 02:13:17PM -0800, Linus Torvalds wrote:
>>
>> But I'm still missing the part where you show that there is any actual
>> use case that makes sense, and that actually improves performance.
>> Maybe it's been posted somewhere else, but the thing is, you're asking
>> _me_ to pull, and as a result you need to convince _me_ that this is a
>> good idea. So if it's been posted/discussed extensively elsewhere,
>> please point to those discussions.
>
> The main use-case is bulk encryption/hashing in user-space. For
> example, on Sparc Niagara2 you need to use SPU (Stream Processing
> Unit) in order to do crypto at 10Gb/s over the network. Because
> of the hardware design, it is difficult to make use of the SPU
> directly in user-space, unless you dedicate the SPU to one single
> thread/user.

The N2 SPU is not accessible at all from userspace.

> However, this is something that has been considered and can be
> easily added. The idea is to first add symmetric key storage
> capability to the existing in-kernel keyring API. Once that is
> done we can easily add a new setsockopt to the crypto user-interface
> that retrieves the key from the kernel keyring instead of getting
> it directly from user-space.

That indeed would be real interesting.