Re: [Qemu-devel] [PATCH v14 0/2] virtio-crypto: virtio crypto device specification

[Gonglei (Arei)]

Hi Stefan,

>
> Subject: Re: [Qemu-devel] [PATCH v14 0/2] virtio-crypto: virtio crypto device
> specification
> 
> On Mon, Dec 26, 2016 at 02:38:29AM +0000, Gonglei (Arei) wrote:
> > Both Alex and Stefan mentioned that the process of create/close a session
> > makes we have a least one full round-trip cost from guest to host to guest
> > to be able to send any data for symmetric algorithms. It gets ourself into
> > synchronization troubles in some scenarios like a web server handling lots
> > of small requests whose algorithms and keys are different.
> >
> > Because the virtio crypto specification has not been voted yet and v15 is on
> the way.
> > I'd like to make some changes in order to support those scenarios better.
> That means
> > we will support one-blob request (no sessions) as well for symmetric
> > algorithms, including HASH, MAC services. The benefit is obvious for
> > HASH service because it's usually a one-blob operation.
> >
> > The main changes will be:
> >  1) using the flag property of struct virtio_crypto_op_header to identify 
> > the
> >     type of crypto request. Aka Is it a session-based or non-session
> request?
> >     The flag is not used currently, so we can make use of it.
> >
> >  2) extending virtio_crypto_*_para structures, for example, add the content
> of
> >     struct virtio_crypto_cipher_session_para into struct
> virtio_crypto_cipher_para.
> >     It's true that will increase the size of each crypto request after this
> change.
> >
> > Does it make sense? Thanks!
> 
> That sounds good.  Hopefully many crypto API users only use a single
> operation and can therefore benefit from this optimization.
> 
Thanks for your feedback. I'll start this work.

Regards,
-Gonglei