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Re: [WARNING] Intel Skylake/Kaby Lake processors: broken hyper-threading




On Sun, Jun 25, 2017 at 09:19:36AM -0300, Henrique de Moraes Holschuh wrote:
[...]
> Apparently, Intel had indeed found the issue, *documented it* (see
> below) and *fixed it*.  There was no direct feedback to the OCaml
> people, so they only found about it later.
[...]
> We do not have enough information at this time to know how much software
> out there will trigger this specific defect.
> 
> One important point is that the code pattern that triggered the issue in
> OCaml was present on gcc-generated code.  There were extra constraints
> being placed on gcc by OCaml, which would explain why gcc apparently
> rarely generates this pattern.
> 
> The reported effects of the processor defect were: compiler and
> application crashes, incorrect program behavior, including incorrect
> program output.
> 
> 
> What we know about the microcode updates issued by Intel related to
> these specific errata:
> 
> Fixes for processors with signatures[1] 0x406E3 and 0x506E3 are
> available in the Intel public Linux microcode release 20170511.  This
> will fix only Skylake processors with model 78 stepping 3, and model 94
> stepping 3.  The fixed microcode for these two processor models reports
> revision 0xb9/0xba, or higher.
> 
> Apparently, these errata were fixed by microcode updates issued in early
> April/2017.  Based on this date range, microcode revision 0x5d/0x5e (and
> higher) for Kaby Lake processors with signatures 0x806e9 and 0x906e9
> *might* fix the issue.  We do not have confirmation about which
> microcode revision fixes Kaby Lake at this time.

so in conclusion: don't buy intel. At least in future.

I must say I'm utterly disappointed by this crap. "hey there is a hug bug, we
dont tell you what it is exactly, or how we fixed it, but YOU MUST INSTALL THIS
BINARY BLOB TO FIX IT. (and btw, this is for skylake, for kaby lake, ahem, maybe,
we have no idea, but do install that crap^wblob too.")

Are there any other public bug reports which got fixed by this, or is the
ocaml issue the only known issue which gets fixed by installing this microcode
update?


(and I hope this were obvious, but I guess it's not, so: I'm saying Intel sold and
still is selling us crap here, not Henrique, who tiredlessly tries to help dealing
with that crap. Thank you, Henrique, for this, that's really nice of you.)

-- 
cheers,
	Holger, hardware *is* software…

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