Messages in this thread | | | Date | Wed, 10 Jun 2009 13:02:44 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] X86: cpu_debug support for VIA / Centaur CPU's |
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* H. Peter Anvin <hpa@kernel.org> wrote:
> Ingo Molnar wrote: > > > > MSRs should really be enumerated along CPU features. They will be > > accessed if a CPU offers that CPU feature. > > > > Nice in theory, but so many MSRs have to be enumerated with obscure test > combinations, that it really isn't practical in the general case. That > is why we have the safe MSR variants. > > > > > Yeah, the safe read should never fault - there should be all > > zeroes or an error return. > > > > Error return, MSRs #GP if not present. All zero means a present > MSR (which is zero.)
yes, of course - i meant the /debug/x86/cpu/* behavior: it should either result zeroes, or should return -EINVAL. (probably the latter)
Ingo
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