Messages in this thread | | | Date | Tue, 12 Jun 2012 13:58:23 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] perf/x86: check ucode before disabling PEBS on SandyBridge |
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On 06/12/2012 01:56 PM, Borislav Petkov wrote: > On Tue, Jun 12, 2012 at 01:42:07PM -0700, H. Peter Anvin wrote: >> I personally don't know of any valid use case for per-core loads, and >> it sounds like a horrid idea. > > Vehemently agreed. > > However, last time we talked about Ingo mentioned some possibility > of having different microcode versions on different CPUs: > http://lkml.indiana.edu/hypermail/linux/kernel/1105.3/00749.html > > Hmm... > >> And yes, I would prefer a single sysfs file, or better yet a plain old >> device node. > > Also agreed. >
There is a difference here. Mixed steppings or even mixed CPUs are, indeed, supported (even things like Nehalem + Westmere in the same system). However, the notion is that we should upload the *entire set* of microcodes to the kernel, and let it flash the appropriate one into each CPU.
This may result in different version number on different CPUs.
-hpa
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