On Tue, 2018-07-03 at 11:06 +0200, Paolo Bonzini wrote: > On 03/07/2018 10:48, Robert Hoo wrote: > >> > >> However, I suggest adding it to the FeatureWord enum, since everything > >> that handles FeatureWord applies to this new kind of MSR as well. > >> Currently FeatureWord is only for CPUID leaves, but it doesn't have to > >> be like that. > >> > > I think this will be changing struct FeatureWordInfo, which is designed > > for cpuid enumerations. You must not want to do that. May I know more > > details about your thought? > > The simplest way is to put CPUIDs first and MSRs second in FeatureWord. > Then you can do > > FEAT_XSAVE_COMP_LO, /* CPUID[EAX=0xd,ECX=0].EAX */ > FEAT_XSAVE_COMP_HI, /* CPUID[EAX=0xd,ECX=0].EDX */ > + FEATURE_WORDS_NUM_CPUID, > + FEATURE_WORDS_FIRST_MSR = FEATURE_WORDS_NUM_CPUID, > + FEAT_MSR_ARCH_CAPABILITIES = FEATURE_WORDS_FIRST_MSR, > FEATURE_WORDS, > }; > > #define FEATURE_WORDS_NUM_MSRS (FEATURE_WORDS - \ > FEATURE_WORDS_FIRST_MSR) > > Then the existing loops that use FeatureWordInfo can go up to > FEATURE_WORDS_NUM_CPUID.
Emm... Understand your point now. It is a little risky, all references to FEATURE_WORDS need to be updated carefully. OK, let me try to think in this way. Perhaps, I'll need to define a new 'struct FeautureWordMsrInfo' to describe feature words from MSR, in parallel to current FeatureWordInfo (or better rename it to FeatureWordCpuidInfo). > > Thanks, > > Paolo > > > And, if I implemented ARCH_CAPABILITIES-bits features in FeatureWord, > > then no necessity of having it in kvm_msr_entries, right? > And would you help confirm with my this point?
