Re: [Qemu-devel] [PATCH 0/4] net-bridge: rootless bridge support for qemu

[Anthony Liguori <aliguori@us.ibm.com>]

Avi Kivity wrote:
>> The model you're advocating (privileged process handing over a fd) is 
>> not as secure because it requires that the management daemon runs as 
>> a privileged user.
>
> Or it can acquire an fd from a privileged helper and pass it on or 
> conjure it some other way.

So qemu should not be allowed to interact with a privileged helper on 
it's own?  I can't tell what your objection here is.  Do you want people 
to just not use qemu directly from the command line?

>>   There's nothing about this that prevents the use of a management 
>> framework.  In fact, had this existed when libvirt was first written, 
>> I'd hope libvirt would have used this mechanism instead of fd 
>> inheritance.
>>
>> Management software is really just another user.  We really want 
>> management software to run unprivileged as much as possible.
>
> I'd like to see qemu confined to managing a single guest and not 
> expand to system management.  We have enough to do without taking over 
> management systems and security.
>
> Bridged network configuration is painful now, but only for a handful 
> of users (us developers).  For the vast majority it is handled behind 
> their back by management, which has to deal with a bunch of privileged 
> stuff anyway (assigned LVM volumes, assigned pci and usb devices, 
> setting up the bridge, large pages, guest priorities).  Why are we 
> adding code to benefit so few people, many of whom don't really use 
> qemu as users?

I strongly disagree with the way you separate users who use management 
software from people who invoke qemu directly.  libvirt and virt-manager 
are existence proofs that management software heavily relies on the 
defaults and mechanisms we establish within qemu.  We can say all we 
want about how management software should do things but the best way is 
to make it easy for them to do the right thing.

-- 
Regards,

Anthony Liguori