Re: [RFC 16/16] lpfc: vmid: Introducing vmid in io path.

Paolo Bonzini
2020-08-06T17:24:41Z

On 06/08/20 14:34, Muneendra Kumar M wrote:
> 3) As part of this interface user/deamon will provide the details of VM such
> as UUID,PID on VM creation to the transport .

The VM process, or the container process, is likely to be unprivileged
and cannot obtain the permissions needed to do this; therefore, you need
to cope with the situation where there is no PID yet in the cgroup,
because the tool that created the VM or container might be initializing
the cgroup, but it might not have started the VM yet. In that case
there would be no PID.

Would it be possible to pass a file descriptor for the cgroup directory
in sysfs, instead of the PID?

Also what would the kernel API look like for this? Would it have to be
driver-specific?

Paolo

> 4) With VM PID information we need to find the associated blkcg and needs to
> update the UUID info in blkio_cg_ priv_data.
> 5) Once we update the blkio_cg_ priv_data with vmid all the io’s issued from
> VM will have the UUID info as part of blkcg.