Messages in this thread | | | Date | Wed, 25 Jul 2012 15:39:57 +0400 | From | Vladimir Davydov <> | Subject | Re: [PATCH 2/2] cpu: intel, amd: mask cleared cpuid features |
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On 07/25/2012 02:43 PM, Borislav Petkov wrote: > On Wed, Jul 25, 2012 at 02:31:23PM +0400, Vladimir Davydov wrote: >> So, you prefer adding some filtering of /proc/cpuinfo into the >> mainstream kernel > That's already there right? And your 1/2 patch was making toggling those > bits easier. > >> (not now, later, for LXC to work) instead of enabling clearcpuid boot >> option to mask CPUID features? IMO, the latter would look clearer. > Yes, but for reasons noted earlier, you cannot tweak all hardware CPUID > features as you want them. > > So, having a software-only layer of tweaking /proc/cpuinfo or something > different you can come up with is the only option you have. > > And even in that case, applications running in the container which > execute CPUID might fail in a strange manner when the corresponding > /proc/cpuinfo flag was cleared by you intentionally but the hardware > CPUID flag is there. In such situations, issues like that should > probably be sorted on a case-by-case basis I guess. > > Thanks. >
We've agreed that tweaking CPUID bits in kernel is not a good idea and it is better to think about virtualization of /proc/cpuinfo and using msr-tools.
Thank you for your time and feedback.
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