Re: Balloon driver?

Dor Laor
2007-06-06T10:24:50Z

>> >I want to try the balloon driver. Do we have it in any git tree?
>> >
>> >The git tree I am having now only has master branch, and nothing
else.
>> >
>> >(Maybe the balloon driver is not working yet, but I am curious when
>> >see the userspace code in user/)
>> >
>> >Thanks,
>> >Jun
>>
>> You're welcome to test it, it is under
>> git://kvm.qumranet.com/home/dor/src/linux-2.6
>> Checkout the build-trunk branch.
>>
>> I don't have the time to merge it currently. Note that there are also
>> some more balloon drivers for other architecture (s390).
>>
>> The Linux guest driver change the balloon size using a simple char
>> device.
>
>Now I see the userspace tool again, and it seems it must be used from
>inside the guest??

That's right. That's the Linux guest side implementation.
For windows we use the vmchannel option in qemu (qemu/hw/hypercall)
interface. It is a qemu device from the host side that can be connected
to tcp/unix socket. The guest sees it as a pci device.
Both ends can define any protocol over the channel.

So our windows guest passes balloon inflate/deflate commands/acks.

What's your motivation of ballooning? If it's important I can add the
pci interface + push it upstream.
>
>So we cannot balloon up/down a guest from host machine?
>
>I will try to see if it works.
>
>Thanks,
>Jun