Re: [Qemu-devel] [PATCH 3/4] cryptodev-vhost-user: add crypto session handler

[Gonglei (Arei)]

> -----Original Message-----
> From: Paolo Bonzini [mailto:address@hidden
> Sent: Tuesday, November 28, 2017 7:20 PM
> To: Gonglei (Arei); address@hidden
> Cc: address@hidden; Huangweidong (C); address@hidden; Zhoujian
> (jay); address@hidden; longpeng; address@hidden;
> address@hidden
> Subject: Re: [PATCH 3/4] cryptodev-vhost-user: add crypto session handler
> 
> On 28/11/2017 12:06, Gonglei (Arei) wrote:
> >>> You mean we can share control virtqueue to DPDK as well? Like data
> queues?
> >> I don't know :) but why not?
> >>
> > Current there are two main reasons for this design:
> >
> > 1) we should use another cpu to polling the control virtqueue, which is
> expensive.
> 
> IIRC DPDK also supports interrupt mode, doesn't it?  Is it possible to
> do interrupt mode for some virtqueues and poll mode for others?
> 

The intel guy Tan (Ccing) said to me:

" Interrupt mode for vhost-user is still not supported in current 
implementation. But we are evaluating the necessity now.

And yes, the mode (polling or interrupt) can be different for different 
queues."

> > 2) we should copy the logic of parsing control message to DPDK, which break
> >  current layered architecture .
> 
> But isn't it already a layering violation that you're adding *some*
> control messages to the vhost-user protocol?  I am not sure why only
> these two are necessary.
> 
Sorry, but I don't think this is layering violation, just like 
"vhost_net_set_mtu"
for vhost-net and "vhost_vsock_set_guest_cid_op" for vhost_vsock. They're all
device-specific messages. Aren't they?

Thanks,
-Gonglei

> Paolo
> 
> > I'm not sure if there are any other hidden issues for future scalability, 
> > such as
> > using Qemu to manage some control messages, avoiding D-Dos attack etc.
> >
> > Thanks,
> > -Gonglei