Re: [RFC][PATCH] vhost/vsock: Add vsock_list file to map cid with vhost tasks

Steven Rostedt
2021-05-13T16:08:52Z

On Thu, 13 May 2021 16:57:34 +0100
Stefan Hajnoczi <stefanha@redhat.com> wrote:

> This approach relies on process hierarchy of the VMM (QEMU).
> Multi-process QEMU is in development and will allow VIRTIO devices to
> run as separate processes from the main QEMU. It then becomes harder to
> correlate a VIRTIO device process with its QEMU process.

And we need to know all these mapping regardless, as we need to map each
thread / process to the vCPU in order to correlate between host thread and
vCPU thread for showing in KernelShark.

Thus this mapping to find the main thread/process needs to be done
regardless.

>
> So I think in the end this approach ends up being as fragile as parsing
> command-lines. The kernel doesn't really have the concept of a "VM" that
> the vhost_vsock is associated with :). Maybe just parse QEMU and crosvm
> command-lines?
>

That's what we do now, and it already broke once, and even parsing the
command line wont be enough for the stated reasons above.

-- Steve