cvs commit: src/sys/amd64/amd64 mp_machdep.c src/sys/amd64/include cpufunc.h src/sys/i386/i386 mp_machdep.c src/sys/i386/include cpufunc.h

[Poul-Henning Kamp]

In message <4287B12C.9080903 at freebsd.org>, Colin Percival writes:
>Nate Lawson wrote:
>> Every general-purpose machine has measurable timing side channels.  The
>> question is merely one of bandwidth.
>
>Absolutely.  Most covert channels operate at up to a few kbps; this covert
>channel operates at several Mbps.

Not only that, but the measurement precision is much better than for more
indirect inspection methods like ps(1).

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
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FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.