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

Paolo Bonzini
2020-08-06T18:41:55Z

On 06/08/20 18:26, Muneendra Kumar M wrote:
> Hi Paolo,
>
>> 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.
>
> Agreed.A
> small doubt. If the VM is started (running)then we can have the PID and we
> can use the PID?

Yes, but it's too late when the VM is started. In general there's no
requirement that a cgroup is setup shortly before it is populated.

>> Would it be possible to pass a file descriptor for the cgroup directory in
>> sysfs, instead of the PID?
> Yes we can do that.
>> Also what would the kernel API look like for this? Would it have to be
>> driver-specific?
>
> The API should be generic and it should not be driver-specific.

So it would be a new file in /dev, whose only function is to set up a
UUID for a cgroup?

Paolo