-----Original Message-----
From: Greg KH (gregkh@linuxfoundation.org)
[mailto:gregkh@linuxfoundation.org]
Sent: Thursday, July 19, 2012 7:29 PM
To: KY Srinivasan
Cc: Paolo Bonzini; devel@linuxdriverproject.org; linux-kernel@vger.kernel.org;
virtualization@lists.osdl.org
Subject: Re: 0xB16B00B5? Really? (was Re: Move hyperv out of the
drivers/staging/ directory)

On Thu, Jul 19, 2012 at 10:30:38PM +0000, KY Srinivasan wrote:

quoted

quoted

quoted

As you know, this ID has been in use for a long time now. While the

hypervisor

quoted

quoted

quoted

does not interpret the guest ID that is registered, I am not sure what

dependencies

quoted

there might be on this value.

Could you please go find out the answer to this?

That is easier said than done. I have sent emails out asking this very question

and I have

quoted

not received a definitive answer yet. Not knowing if and when I can get a

definitive

quoted

answer here, I chose the least risky approach in my patch.

What happens if you test with different values?

Nothing and that is not the issue. Current MSFT hypervisors don't interpret this
ID value while future versions might. However, this ID can be retrieved by the parent
partition and can be used by the management stack today (that is what I am told). 

quoted

quoted

If, as you originally stated, there is a range of values we can use,
then we should probably use another one, right?

On the Windows side this ID namespace is managed well.

It is?  How is this managed?  What does this tell the hypervisor?  What
changes with the different values?

quoted

However on the Linux side, we have really had this current ID in use
for almost five years now. I am not aware of any pool of IDs available
for Linux usage except that Linux IDs be distinct from the guest IDs
in use by MSFT operating systems. If I were to change the guest ID, I
would probably want to comply with the MSFT guidance on constructing
these IDs (although not all fields may be relevant for Linux).

What are those rules?

Here is the link that describes how the guest ID should be composed:

http://msdn.microsoft.com/en-us/library/windows/hardware/ff542653%28v=vs.85%29.aspx


Regards,

K. Y