Re: [PATCH net-next v2 0/4] vsock: Add flags field in the vsock address

[Stefano Garzarella]

Hi Andra,

On Fri, Dec 04, 2020 at 07:02:31PM +0200, Andra Paraschiv wrote:
> vsock enables communication between virtual machines and the host they are
> running on. Nested VMs can be setup to use vsock channels, as the multi
> transport support has been available in the mainline since the v5.5 Linux kernel
> has been released.
>
> Implicitly, if no host->guest vsock transport is loaded, all the vsock packets
> are forwarded to the host. This behavior can be used to setup communication
> channels between sibling VMs that are running on the same host. One example can
> be the vsock channels that can be established within AWS Nitro Enclaves
> (see Documentation/virt/ne_overview.rst).
>
> To be able to explicitly mark a connection as being used for a certain use case,
> add a flags field in the vsock address data structure. The "svm_reserved1" field
> has been repurposed to be the flags field. The value of the flags will then be
> taken into consideration when the vsock transport is assigned. This way can
> distinguish between different use cases, such as nested VMs / local communication
> and sibling VMs.

the series seems in a good shape, I left some minor comments.
I run my test suite (vsock_test, iperf3, nc) with nested VMs (QEMU/KVM), 
and everything looks good.

Note: I'll be offline today and tomorrow, so I may miss followups.

Thanks,
Stefano