Re: [RFC PATCH crypto] AES: Add support to Intel AES-NI instructions

Suresh Siddha
2008-12-15T18:27:10Z

On Sun, Dec 14, 2008 at 07:38:42PM -0800, Herbert Xu wrote:
> On Mon, Dec 15, 2008 at 10:19:02AM +0800, Huang Ying wrote:
> >
> > The general x86 implementation is used as the fall back for new AES-NI
> > based implementation. Because AES-NI can not be used in kernel soft_irq
> > context. If crypto layer is used to access general x86 implementation,
>
> Why is that? The VIA PadLock also "touches" the SSE state but we still
> use it on softirq paths.
>
> In fact Suresh told me earlier that your AES instruction wasn't
> going to have the SSE problems that VIA had, is this not the case?

As Huang mentioned, AES instructions touch SSE registers and thus have
different requirements. I agree that we have to do some performance
analysis to come up with the optimized model.

thanks,
suresh