Messages in this thread | | | Date | Wed, 2 Sep 2020 18:59:50 +0200 | From | peterz@infradea ... | Subject | Re: [RFC PATCH] tools/x86: add kcpuid tool to show raw CPU features |
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On Wed, Sep 02, 2020 at 09:52:33AM -0700, Dave Hansen wrote: > On 9/2/20 9:45 AM, peterz@infradead.org wrote: > > On Thu, Aug 27, 2020 at 03:49:03PM +0800, Feng Tang wrote: > >> End users frequently want to know what features their processor > >> supports, independent of what the kernel supports. > >> > >> /proc/cpuinfo is great. It is omnipresent and since it is provided by > >> the kernel it is always as up to date as the kernel. But, it can be > >> ambiguous about processor features which can be disabled by the kernel > >> at boot-time or compile-time. > > > > Let me once again suggest we use CPUID faulting to 'fix' this. > > > > We really should clear the CPUID bits when the kernel explicitly > > disables things. > > > > https://lkml.kernel.org/r/1552431636-31511-18-git-send-email-fenghua.yu@intel.com > > Wouldn't we also have to turn on faulting for all the bits that are > enumerated, but of which the kernel is unaware? > > Right now, a bit that we clearcpuid= and one about which the kernel is > totally unaware look the same.
I mostly care about the things the kernel disables (and thus knows about), the rest is a pass-through IIRC.
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