Re: [Qemu-devel] [PATCH v2 1/5] i386: Add support for IA32_PRED_CMD and IA32_ARCH_CAPABILITIES MSRs

[Robert Hoo]

On Tue, 2018-07-03 at 15:38 +0200, Paolo Bonzini wrote:
> On 03/07/2018 13:07, Robert Hoo wrote:
> >>      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).
> 
> Yes, probably.  The plan seems fine.
> 

> > And, if I implemented ARCH_CAPABILITIES-bits features in
FeatureWord,
> > then no necessity of having it in kvm_msr_entries, right?
> 
Hi Paolo, would you confirm this? I mean your previous patch "KVM: VMX:
support MSR_IA32_ARCH_CAPABILITIES as a feature MSR" is not necessary
now?

> Paolo