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Re: [Qemu-devel] [PATCH v2 1/5] i386: Add support for IA32_PRED_CMD and
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH v2 1/5] i386: Add support for IA32_PRED_CMD and IA32_ARCH_CAPABILITIES MSRs |
Date: |
Tue, 3 Jul 2018 11:06:00 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 |
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.
Thanks,
Paolo
> And, if I implemented ARCH_CAPABILITIES-bits features in FeatureWord,
> then no necessity of having it in kvm_msr_entries, right?