Re: [LAU] Meltdown – Spectre

On Sat, 13 Jan 2018 20:02:28 +0000, Will Godfrey wrote:
>On Sat, 13 Jan 2018 20:52:36 +0100
>David Kastrup <dak@gnu.org> wrote:
>
>>Ralf Mardorf <ralf.mardorf-ZCLZIpdjs0kJGwgDXS7ZQA@public.gmane.org>
>>writes:
>>
>>> On Sat, 13 Jan 2018 15:29:27 +0000, Pablo Fernandez wrote:
>>>>El sáb., 13 ene. 2018 13:58, Thomas Pfundt escribió:
>>>>> However, this site doesn't list your Celeron G as vulnerable:
>>>>> https://security-center.intel.com/advisory.aspx?intelid=INTEL-SA-00088&languageid=en-fr
>>>>> Do you even need to concern with the patch and performance at this
>>>>> point?
>>>
>>> That is interesting news. I'll forward this, since actually it's
>>> claimed that all x86 CPUs since the Pentium Pro from 1995 suffer
>>> from this issue.
>>>
>>> Does anybody know how to value this information from Intel?
>>
>>The vulnerability is speculative execution in connection with memory
>>fetch. Basically, you make a conditional indirect branch via the
>>location you want to read out with the condition being later figured
>>out as false. The execution is abandoned at that time, but the
>>indirect branch has invalidated previous contents of the cache
>>depending on the abandoned target. Now you use timing registers in
>>connection with accesses in order to figure out just where the cache
>>is no longer valid.
>>
>>Since kernel and user processes generally share the same virtual
>>address space for efficiency reasons (though obviously not the same
>>permissions)...
>>
>>Basically, I'd be surprised about exceptions.
>>
>
>Bearing in mind Intel's past behaviour

Hi,

I'm not aware of Intel's past behaviour, since I was an unsatisfied AMD
user. Now with my first Intel based machine I'm still satisfied, but
since a few weeks I'm uncertain. For some usage I need security, for
other usage I need performance. I could separate both desires, but one
link claims I could disable a patch set using "nopti" and one changelog
claims I could disable a patch set using "nokasier" and that is just
about meltdown, not about spectre, let alone the third nameless
vulnerability ... or does Meltdown and/or Spectre cover the third
thingy, too?

>I regard missing entries in that list as simply meaning those CPUs
>have not been tested, not that they in the clear.
          and never will be tested, since they are discontinued or
          something like this ;)

That is my guess, too, since they formally mentioned "For non-Intel
based systems please contact your system manufacturer or microprocessor
vendor (AMD, ARM, Qualcomm, etc.) for updates." To me that sounds much
like an insincerely "we're all in the same boat" statement, while CPUs
from other vendors might be a little bit vulnerable, too, seemingly
only Intel suffers from a disaster.

IOW you confirmed my worries.

Regards,
Ralf
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Received on Sun Jan 14 00:15:02 2018