On Mon, Jan 20, 2020 at 11:17:35AM +0100, Stefano Garzarella wrote: > On Mon, Jan 20, 2020 at 10:06:10AM +0100, David Miller wrote: > > From: Stefano Garzarella <sgarzare@xxxxxxxxxx> > > Date: Thu, 16 Jan 2020 18:24:26 +0100 > > > > > This patch adds 'netns' module param to enable this new feature > > > (disabled by default), because it changes vsock's behavior with > > > network namespaces and could break existing applications. > > > > Sorry, no. > > > > I wonder if you can even design a legitimate, reasonable, use case > > where these netns changes could break things. > > I forgot to mention the use case. > I tried the RFC with Kata containers and we found that Kata shim-v1 > doesn't work (Kata shim-v2 works as is) because there are the following > processes involved: > - kata-runtime (runs in the init_netns) opens /dev/vhost-vsock and > passes it to qemu > - kata-shim (runs in a container) wants to talk with the guest but the > vsock device is assigned to the init_netns and kata-shim runs in a > different netns, so the communication is not allowed > But, as you said, this could be a wrong design, indeed they already > found a fix, but I was not sure if others could have the same issue. > > In this case, do you think it is acceptable to make this change in > the vsock's behavior with netns and ask the user to change the design? David's question is what would be a usecase that's broken (as opposed to fixed) by enabling this by default. If it does exist, you need a way for userspace to opt-in, module parameter isn't that. > > > > > I am totally against adding a module parameter for this, it's > > incredibly confusing for users and will create a test scenerio > > that is strongly less likely to be covered. > > > > Got it, I'll remove the module parameter! > > Thanks, > Stefano
