On Wed, 29 Jul 2020 at 15:27, Ben Greear <greearb@xxxxxxxxxxxxxxx> wrote: > > On 7/28/20 11:06 PM, Ard Biesheuvel wrote: > > On Wed, 29 Jul 2020 at 01:03, Ben Greear <greearb@xxxxxxxxxxxxxxx> wrote: > >> > >> Hello, > >> > >> As part of my wifi test tool, I need to do decrypt AES on the CPU, and the only way this > >> performs well is to use aesni. I've been using a patch for years that does this, but > >> recently somewhere between 5.4 and 5.7, the API I've been using has been removed. > >> > >> Would anyone be interested in getting this support upstream? I'd be happy to pay for > >> the effort. > >> > >> Here is the patch in question: > >> > >> https://github.com/greearb/linux-ct-5.7/blob/master/wip/0001-crypto-aesni-add-ccm-aes-algorithm-implementation.patch > >> > >> Please keep me in CC, I'm not subscribed to this list. > >> > > > > Hi Ben, > > > > Recently, the x86 FPU handling was improved to remove the overhead of > > preserving/restoring of the register state, so the issue that this > > patch fixes may no longer exist. Did you try? > > > > In any case, according to the commit log on that patch, the problem is > > in the MAC generation, so it might be better to add a cbcmac(aes) > > implementation only, and not duplicate all the CCM boilerplate. > > > > Hello, > > I don't know all of the details, and do not understand the crypto subsystem, > but I am pretty sure that I need at least some of this patch. > Whether this is true is what I am trying to get clarified. Your patch works around a performance bottleneck related to the use of AES-NI instructions in the kernel, which has been addressed recently. If the issue still exists, we can attempt to devise a fix for it, which may or may not be based on this patch. > If you can suggest a patch to try I'll be happy to test it to see how it > performs. > Please share performance numbers of an old kernel with this patch applied, and a recent one without. If that shows there is in fact an issue, we will do something about it. > > -- > Ben Greear <greearb@xxxxxxxxxxxxxxx> > Candela Technologies Inc http://www.candelatech.com
