something like that wont enable 100% coverage (or even reasonable
coverage for most hardware), so it's no replacement for actual hard
testing, but it could push out the domain of minimally tested code quite
a bit and increase the quality of the kernel. Races are always tough and
so are bugs on the side of the hardware, but it's the silly boot-time
crash showstoppers and "device does not work anymore" mistakes that
causes us to lose most of the testers and early adopters.
I'm not really worried about the 1% of bugs that are tough to find and
fix (because they are actually fun to find and fix), i'm worried about
the 99% easy and boring bugs - because they annoy users just as much as
the exciting bugs do. If we fix them faster then there's more time (and
more tester stamina) left for the harder to find bugs.
so i think adding redundancy in form of a simplified hw emulator can
certainly not hurt and fundamentally increases robustness - and it will
definitely reduce the chance for a whole host of stupid bugs that are
not in the hardware but are in the ~4 million lines of Linux driver
codebase. Limits and scalability would also be testable: "if i put 32 of
these networking cards into a Linux box, will the Linux driver blow up".
not that i think this is realistic for any significant portion of the
hardware currently - unless some hw maker starts doing it. But KVM will
have a good portion of the core PC platform emulated (APIC, etc.) - and
that's a nice step forward already.
Ingo
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