Re: 0xB16B00B5? Really? (was Re: Move hyperv out of thedrivers/staging/ directory)

[Greg KH (gregkh@xxxxxxxxxxxxxxxxxxx)]

On Thu, Jul 19, 2012 at 09:22:53PM +0000, KY Srinivasan wrote:
> 
> 
> > -----Original Message-----
> > From: Greg KH (gregkh@xxxxxxxxxxxxxxxxxxx)
> > [mailto:gregkh@xxxxxxxxxxxxxxxxxxx]
> > Sent: Thursday, July 19, 2012 5:07 PM
> > To: KY Srinivasan
> > Cc: Paolo Bonzini; devel@xxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > virtualization@xxxxxxxxxxxxxx
> > Subject: Re: 0xB16B00B5? Really? (was Re: Move hyperv out of the
> > drivers/staging/ directory)
> > 
> > On Thu, Jul 19, 2012 at 02:11:47AM +0000, KY Srinivasan wrote:
> > >
> > >
> > > > -----Original Message-----
> > > > From: Paolo Bonzini [mailto:paolo.bonzini@xxxxxxxxx] On Behalf Of Paolo
> > > > Bonzini
> > > > Sent: Friday, July 13, 2012 6:23 AM
> > > > To: KY Srinivasan
> > > > Cc: Greg KH; devel@xxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > > > virtualization@xxxxxxxxxxxxxx
> > > > Subject: 0xB16B00B5? Really? (was Re: Move hyperv out of the
> > drivers/staging/
> > > > directory)
> > > >
> > > > Il 04/10/2011 21:34, Greg KH ha scritto:
> > > > > diff --git a/drivers/staging/hv/hyperv_vmbus.h
> > b/drivers/hv/hyperv_vmbus.h
> > > > > similarity index 99%
> > > > > rename from drivers/staging/hv/hyperv_vmbus.h
> > > > > rename to drivers/hv/hyperv_vmbus.h
> > > > > index 3d2d836..8261cb6 100644
> > > > > --- a/drivers/staging/hv/hyperv_vmbus.h
> > > > > +++ b/drivers/hv/hyperv_vmbus.h
> > > > > @@ -28,8 +28,7 @@
> > > > >  #include <linux/list.h>
> > > > >  #include <asm/sync_bitops.h>
> > > > >  #include <linux/atomic.h>
> > > > > -
> > > > > -#include "hyperv.h"
> > > > > +#include <linux/hyperv.h>
> > > > >
> > > > >  /*
> > > > >   * The below CPUID leaves are present if
> > > > VersionAndFeatures.HypervisorPresent
> > > >
> > > > git's rename detection snips away this gem:
> > > >
> > > > +#define HV_LINUX_GUEST_ID_LO		0x00000000
> > > > +#define HV_LINUX_GUEST_ID_HI		0xB16B00B5
> > > > +#define HV_LINUX_GUEST_ID		(((u64)HV_LINUX_GUEST_ID_HI
> > > > << 32) | \
> > > > +					   HV_LINUX_GUEST_ID_LO)
> > > >
> > > > Somone was trying to be funny, I guess.
> > > >
> > > > KY, I suppose you have access to Hyper-V code or can ask someone who
> > does.
> > > > Is this signature actually used in the Hyper-V host code?
> > >
> > > Paolo,
> > >
> > > As I noted earlier, this is just a guest ID that needs to be registered with the
> > > hypervisor.  Thanks  for reporting this issue and on behalf of Microsoft, I would
> > > like to  apologize for this offensive string. I have submitted a patch to fix this
> > issue.
> > 
> > You only changed it to be in decimal, you did not change the id at all.
> > Is there some reason why you can not change it?  You said there was a
> > reserved range of ids that could be used, perhaps just pick another one?
> > What is the valid range that can be used here?
> 
> Greg,
> 
> As you know, this ID has been in use for a long time now. While the hypervisor
> does not interpret the guest ID that is registered, I am not sure what dependencies
> there might be on this value.

Could you please go find out the answer to this?

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

thanks,

greg k-h
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