RE: [PATCH 1/1] Drivers: hv: Cleanup the guest ID computation

[KY Srinivasan]

> -----Original Message-----
> From: Olaf Hering [mailto:olaf@xxxxxxxxx]
> Sent: Wednesday, July 25, 2012 4:17 AM
> To: KY Srinivasan
> Cc: gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> devel@xxxxxxxxxxxxxxxxxxxxxx; apw@xxxxxxxxxxxxx
> Subject: Re: [PATCH 1/1] Drivers: hv: Cleanup the guest ID computation
> 
> On Tue, Jul 24, K. Y. Srinivasan wrote:
> 
> 
> > +/*
> > + * The guest OS needs to register the guest ID with the hypervisor.
> > + * The guest ID is a 64 bit entity and the structure of this ID is
> > + * specified in the Hyper-V specification:
> > + *
> > + * http://msdn.microsoft.com/en-us/library/windows/
> > + * hardware/ff542653%28v=vs.85%29.aspx
> > + *
> > + * While the current guideline does not specify how Linux guest ID(s)
> > + * need to be generated, our plan is to publish the guidelines for
> > + * Linux and other guest operating systems that currently are hosted
> > + * on Hyper-V. The implementation here conforms to this yet
> > + * unpublished guidelines.
> > + *
> > + *
> > + * Bit(s)
> > + * 63 - Indicates if the OS is Open Source or not; 1 is Open Source
> > + * 62:56 - Os Type; Linux is 0x100
> > + * 55:48 - Distro specific identification
> > + * 47:16 - Linux kernel version number
> > + * 15:0  - Distro specific identification
> > + *
> > + *
> > + */
> > +
> > +#define HV_LINUX_VENDOR_ID		0x8100
> 
> I suggest to drop bit 63, why would the hypervisor care about that
> weird detail?

Hypervisor does not care, but on the host side we plan to use this to track
the kind of guest operating systems currently hosted.

Regards,

K. Y
 

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