Re: [Qemu-devel] [virtio-dev] Re: [PATCH v13 1/2] virtio-crypto: Add virtio crypto device specification

[Gonglei (Arei)]

> From: address@hidden [mailto:address@hidden
> On Behalf Of Michael S. Tsirkin
> Sent: Thursday, November 10, 2016 9:03 PM
> address@hidden; Claudio Fontana; address@hidden; Wubin
> (H)
> Subject: Re: [virtio-dev] Re: [Qemu-devel] [PATCH v13 1/2] virtio-crypto: Add
> virtio crypto device specification
> 
> On Thu, Nov 10, 2016 at 02:25:44AM +0000, Gonglei (Arei) wrote:
> >
> > >
> > > Subject: [virtio-dev] Re: [Qemu-devel] [PATCH v13 1/2] virtio-crypto: Add
> virtio
> > > crypto device specification
> > >
> > > On Wed, Nov 09, 2016 at 01:11:20AM +0000, Gonglei (Arei) wrote:
> > > > Nope, Actually I kept those description here is because I wanted to
> represent
> > > each packet
> > > > Intuitionally, otherwise I don't know how to explain them only occupy 
> > > > one
> > > entry in desc table
> > > > by indirect table method.
> > >
> > > whether to use the indirect method should not be up to device.
> > > I don't see where does the spec require indirect method,
> > > ANY_LAYOUT is implied so spec should not dictate that IMO.
> > >
> > Yes, I reread the virtio spec. And
> >
> > 2.4.4 says:
> >  " The framing of messages with descriptors is independent of the contents
> of the buffers."
> >
> > 2.4.4.2 says:
> >  "The driver SHOULD NOT use an excessive number of descriptors to
> describe a buffer."
> >
> > For virtio-crypto, I think I can just add a NOTE to remind people using 
> > indirect
> method
> > if they want to get better performance in production environment, can I?
> >
> >
> > Thanks,
> > -Gonglei
> 
> I'm not sure why frankly. Is there a reason crypto is special here?
> 
I just think each virtio crypto device maybe use many entries for one request. 
But you are right, whether to use the indirect method should not be up to 
device.

The device shouldn't touch this. 

Thanks,
-Gonglei