Re: [Qemu-devel] Question about add AF_ALG backend for virtio-crypto

[Daniel P. Berrange]

On Tue, Jan 10, 2017 at 09:03:45AM +0000, Gonglei (Arei) wrote:
> Hi,
> 
> > 
> > On Mon, Jan 09, 2017 at 01:43:10PM +0000, Stefan Hajnoczi wrote:
> > > On Mon, Jan 09, 2017 at 03:04:55PM +0800, Longpeng (Mike) wrote:
> > > > I'm one of Gonglei's virtio-crypto project members, and we plan to add a
> > AF_ALG
> > > > backend for virtio-crypto(there's only builtin-backend currently).
> > > >
> > > > I found that Catalin, Paolo and Stefan had discussed about this in 2015
> > > > (http://www.spinics.net/lists/kvm/msg115457.html), but it seems that
> > Catalin
> > > > didn't do it, so I'm confuse about wether it is need to add a AF_ALG
> > backend.
> > > >
> > > > Do you have any suggestion? Thanks :)
> > >
> > > I have no objections to an AF_ALG backend in QEMU.
> > 
> > Rather than do another backend for virtio-crypto, IMHO, we should have
> > an AF_ALG impl of the crypto/ APIs. That way any potential performance
> > benefits will enhance our LUKS encryption code too.
> > 
> According to the currently schemas of crypto/ APIs, we can't choose the
> specific backend dynamically. This is a limitation for virtio-crypto
> device I think.

Do we really need to be able to choose the backend explicitly. If the AF_ALG
backend is faster, why would you simply not use that automatically if it is
available. I'm not seeing an obvious need for dynamically choosing between
backends.

Regards,
Daniel
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