Messages in this thread | | | Date | Mon, 8 Sep 2008 17:23:30 +0200 | From | Ingo Molnar <> | Subject | Re: [BUG] x86 kenel won't boot under Virtual PC |
| |
* Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Sun, 7 Sep 2008, H. Peter Anvin wrote: > > > > Under that logic we shouldn't even have CPU configurables, since you want it > > to "just work" whatever crap you're running on. That is EXACTLY what > > CONFIG_X86_GENERIC means > > I dunno.. Event he help-text doesn't actually agree with that: > > config X86_GENERIC > bool "Generic x86 support" > depends on X86_32 > help > Instead of just including optimizations for the selected > x86 variant (e.g. PII, Crusoe or Athlon), include some more > generic optimizations as well. This will make the kernel > perform better on x86 CPUs other than that selected. > > This is really intended for distributors who need more > generic optimizations. > > Also, quite frankly, while the CPU processor type message says > > The kernel will not necessarily run on earlier architectures than > the one you have chosen, e.g. a Pentium optimized kernel will run on > a PPro, but not necessarily on a i486. > > I thought you agreed that CPU virtualization can be a problem? That > was the whole excuse for why the dynamic code was changed. Why would > it not be true for the static code? > > The fact is, if you want to run on a Core2 or other modern CPU, then > "Virtual PC" is apparently buggy in this respect. You worked around it > for the dynamic choice - but that's totally _pointless_ if you then > don't want to work around it for the static one.
yes. X86_P6_NOPS is a totally insignificant optimization and if it makes _any_ CPU not boot (be that virtual or real), then it's frankly not worth it.
David, exactly how does the kernel fail to boot with latest -git? (v2.6.27-rc5-313-g64f996f or later) Does detect_nopl() run? It really should, and it should detect the non-working instructions.
Ingo
| |