Re: [External] [RFC] vsock: add multiple transports support for dgram

[Jorgen Hansen <jhansen@vmware.com>]

> On 7 Apr 2021, at 20:25, Jiang Wang . <jiang.wang@bytedance.com> wrote:
> 
> On Wed, Apr 7, 2021 at 2:51 AM Jorgen Hansen <jhansen@vmware.com> wrote:
>> 
>> 
>>> On 6 Apr 2021, at 20:31, Jiang Wang <jiang.wang@bytedance.com> wrote:
>>> 
>>> From: "jiang.wang" <jiang.wang@bytedance.com>
>>> 
>>> Currently, only VMCI supports dgram sockets. To supported
>>> nested VM use case, this patch removes transport_dgram and
>>> uses transport_g2h and transport_h2g for dgram too.
>> 
>> Could you provide some background for introducing this change - are you
>> looking at introducing datagrams for a different transport? VMCI datagrams
>> already support the nested use case,
> 
> Yes, I am trying to introduce datagram for virtio transport. I wrote a
> spec patch for
> virtio dgram support and also a code patch, but the code patch is still WIP.

Oh ok. Cool. I must have missed the spec patch - could you provide a reference to
it?

> When I wrote this commit message, I was thinking nested VM is the same as
> multiple transport support. But now, I realize they are different.
> Nested VMs may use
> the same virtualization layer(KVM on KVM), or different virtualization layers
> (KVM on ESXi). Thanks for letting me know that VMCI already supported nested
> use cases. I think you mean VMCI on VMCI, right?

Right, only VMCI on VMCI. 

I’ll respond to Stefano’s email for the rest of the discussion.

Thanks,
Jorgen