17 Sep
2019
17 Sep
'19
8:48 a.m.
On 09/17/2019 08:55 AM, Paul Koning via cctalk wrote:
"Spectre" is one of two notorious bugs of
modern CPUs involving speculative execution. I rather doubt that VAX is affected by this
but I suspect others here have a lot more knowledge.
You need an extremely high resolution timer to detect slight
differences in execution time of speculatively-executed
threads. The VAX 11/780 certainly did not do speculative
execution, and my guess is that all VAXen did not, either.
Also, I don't think the timer was high enough resolution to
detect such a difference.
The Alpha did do speculative execution, so it is remotely
possible that you could play such games on that platform.
Without a deep understanding of how these exploits really
work, I'm still a bit skeptical that it could actually be
performed on real-world systems in a shared host data center.
Jon