Xen devel - Jan 2011 - [PATCH]: blacklist new AMD CPUID bits for PV domains

Hi,

there are some new CPUID bits (and leaves) which Dom0 and PV domains 
should not see to avoid trouble, since we don''t emulate the features. 
The most prominent one is a topology leaf, which contains information 
specific to the physical CPU, not the virtual one. To avoid confusion 
(and possibly crashes) due to a confused Dom0 scheduler simply disable 
these bits.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>

-- 
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany


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On 25/01/2011 14:14, "Andre Przywara" <andre.przywara@amd.com>
wrote:
> Hi,
> 
> there are some new CPUID bits (and leaves) which Dom0 and PV domains
> should not see to avoid trouble, since we don''t emulate the
features.
> The most prominent one is a topology leaf, which contains information
> specific to the physical CPU, not the virtual one. To avoid confusion
> (and possibly crashes) due to a confused Dom0 scheduler simply disable
> these bits.
> 
> Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Andre,

You also need to mask these in tools/libxc/xc_cpuid_x86.c, right? The
hypervisor code you modify affects only dom0.

 -- Keir




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