More on the Hyper-V Linux Integration Components

  • Article

by hjanssen on July 20, 2009 03:24pm

Well, there is no easy way to say this, so I am simply going to start this blog with the following line.

Microsoft just submitted source code for the Hyper-V Linux Integration Components to the Linux Kernel Community Under GPL v2.

Well, there's a conversation starter! Are you still all sitting in your chairs???

Let me summarize:

  • Yes, our device driver code was released directly to the Linux Kernel
  • We released the code under GPL v2
  • We are working with Greg Kroah-Hartman so it is ready for the next release of the Linux Kernel, version 2.6.32
  • We will continue to update the driver code to enhance interoperability on an ongoing basis, but it's our hope that other developers in the community will find the code useful and worthy of collaboration.

Fallen off your chair yet?

Microsoft developed the Linux device drivers  to enhance the performance of Linux when virtualized on Windows Server 2008 Hyper-V.  My team and I were responsible for testing and validating the driver components that were contributed for this first release.  

Now, my team and I will be responsible for further developing this code going forward.  (Yes, that does mean that I have gone back to leverage my very early roots as a Kernel programmer. Let the world be warned!!!!). Haiyang Zhang has been working on this code with me, and he will continue to work with me on this going forward.

When I joined Microsoft three years ago, the primary reason was to put my money where my mouth was. You see complaining about something is easy, but it becomes a little more complicated when somebody offers you the opportunity to be part of helping change what you have complained about.

So, three years after taking the job that made me put my money where my mouth was (and still often is!), I for one am EXTREMELY happy to see one of the most significant fruits of our work here in the Microsoft Open Source Technology Center (OSTC). But I have to say, even I would have been hard-pressed to think three years ago that we would consider contributing to the Linux Kernel.

As you know, two years ago Microsoft announced a partnership with Novell, and Tom Hanrahan ran the lab on a day to day basis till about 9 months ago. Since then I have had the pleasure of running the technical side of the execution of that lab under Tom Hanrahan for the OSTC. One of the primary tasks for that lab is to make sure Windows runs well on top of XEN and Linux runs well on top of Hyper-V, and we do this in very close cooperation with Novell.

We do most of this work as an extension to Mike Neil's Hyper-V team.

As part of this, we were asked to help develop and maintain a crucial part of this work called the Linux Integration Components. This code is designed so that Linux can run in an "enlightened mode" on top of Hyper-V (enlightened mode is roughly the Hyper-V equivalent of "paravirtualized mode" for the Xen hypervisor).  Without this driver code, Linux can run on top of Windows, but without the same high performance levels.   It is this device driver code that we are releasing today, directly to the Linux Kernel.

We're  not talking a few hundred lines of code here; we're  talking about roughly 20,000 lines of code.

Is this a Dump and Run from Microsoft? Absolutely not!  We plan to enhance the functionality of this code, and we will continue to work with the Linux Community  to support the drivers and to ensure continued interoperability.

As you can imagine, this was the result of a lot of  hard work: Hiyang Zhang, who has been co-writing this code; Hashir Abdi, who has been testing all this stuff; as well as  Vijay Tewari and Mike Sterling from the Hyper-V team who have been taking care of the Hyper-V side.

And last, but certainly not least, Greg Kroah-Hartman, who has been helping me to make all this code land in the right area in the kernel. He has patiently worked to help me correct my obvious mistakes and to get the code contributed into the kernel.

So where are we today? Well, Greg Kroah-Hartman will make the code visible to the outside world today. (For those who want to get a head start, the code will sit under <your kernel tree>/drivers/staging/hv). After it becomes visible, I will write a few more blogs this week that should help you to understand, build and run them.

The titles I am thinking for these blogs are:

Where do the Linux ICs reside in the kernel tree and how do I build them?

                And

How do I install, configure and run the Linux IC's?

I had almost forgotten how wrapped up you can be once you start writing code again. So I have not gotten much sleep this past week, but it has been a joy to get back into coding again!