Re: [Xen-ia64-devel] RE: _OSI(Linux) == false

[Alex Williamson <alex.williamson@xxxxxx>]

On Fri, 2007-08-17 at 14:13 +0800, Xu, Anthony wrote:
> >
> >   This changeset was just brought to my attention:
> >
> >http://www.kernel.org/hg/linux-2.6/rev/7f6bc8a8fb19
> >
> >In short, newer upstream kernels will return True for _OSI(Windows) and
> >False for _OSI(Linux).  This will cause Linux VT-i domains to get
> >incorrectly identified as Windows guests and do bad things with region
> 4
> >& 5 mapping.
> 
> Does linux call _OSI(Windows)?
> If not, it will not impact XEN.

   We added platform optimizations based on the following assumption:

        On Tue, 2007-05-08 at 10:55 +0800, Xu, Anthony wrote:
>         Run linux,
>         Both __OSI(linux) and __OSI(windows) return true.
>         
>         Run windows,
>         __OSI(linux) return false,
>         __OSI(windows) return true.
>         
>         So if guest FW checks linux first then checks windows.
>         Guest FW can tell which OS is running on top of it.
>         Then Guest FW can tell XEN which OS is running.

We can no longer identify Linux vs Windows in this manner unless we can
make Linux return True for _OSI(linux) when it's running on Xen.  Is
this not the way the code works?  I see the calls to _OSI in the _INI
method of the PCI0 device in the DSDT:


147             If (CondRefOf(_OSI, Local0)) 
148             { 
149                     //Compare linux first. Because \_OSI("Windows 2001") 
still 
150                     //return true while linux running on guest 
151                     If (\_OSI("Linux")) 
152                     { 
153                             Store(0xB2, OST) 
154                     } 
155                     ElseIf (\_OSI("Windows 2001.1")) 
156                     { 
157                             Store(0xB1, OST) 
158                     } 
159                     Else 
160                     { 
161                             Store(0xB0, OST) 
162                     } 
163
164                     Store(0xB0, OST) 
165             } 

Thanks,

        Alex

-- 
Alex Williamson                             HP Open Source & Linux Org.


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