Re: Clarifications about AMD TLB L3 bug

Robert Myers wrote:
> A number of assertions have been made here about the AMD TLB L3 Bug:
> 
> 1. Only affects virtualization.
> 
> 2. Is fixed in 64-bit Linux without a significant performance hit.
> 
> 1. TRUTH: AMD, which knew about the bug before the chip was released,
> falsely made this claim.  The bug apparently affects all workloads,
> potentially resulting in a system freeze.


The truth actually is that it only affects virtualized workloads, 
because the problem occurs when nested page tables are used. Nested page 
tables only are used in virtualization, no other times. AMD never made 
the claim it only affects virtualization, it is actually trying to keep 
that hushed up: I assume because it does not want a virtualization bug 
to be associated with its products since that kind of a reputation would 
be hard to shake off, even if fixed.

> 2. TRUTH: A fix is available under NDA for RHEL 4 and not otherwise
> apparently.
> 
> http://techre****t.com/discussions.x/13721
> 
> http://techre****t.com/discussions.x/13724

How secret can it be if it's open-source?

	Yousuf Khan