On 3/05/2021 1:16 am, David L. Craig wrote:
https://engineering.virginia.edu/news/2021/04/defenseless
doesn't mention if zArchitecture is immune, but I suspect
it is not. Does anybody know for sure?
My mud-brain can barely comprehend this stuff, but...
1. Does this new development rely on "powerful" instructions (as they
exist in application object code) being broken down to simpler
instructions? ("millicode"?)
2. Was not the IBM solution on the Z platform (when activated by the
system's owner) to slow down the whole she-bang such that there was no
timing difference based on the data? (That is, does not the "fix" simply
stop the look-ahead based on predictiveness by just waiting for the real
answer on stuff such that no illegal data access actually occurs?)
3. Does that mean the effectiveness of such previously implemented
"solutions" relies on the "level" at which they are implemented?
So if IBM implemented the "solution" at the "millicode" level then it
might be a real fix not affected by this new scenario, but if it is/was
implemented at a "Princples of Operations" level then it might be
susceptible?
Or have I totally misunderstood the new information? (Ok, let's take
that as read, but cue someone who understands it...)
:)
Cheers,
Greg
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