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SubjectRe: [PATCH v3 4/8] KVM: X86: Split kvm_update_cpuid()
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On 08/07/20 14:33, Xiaoyao Li wrote:
> On 7/8/2020 8:06 PM, Paolo Bonzini wrote:
>> On 08/07/20 08:50, Xiaoyao Li wrote:
>>> Split the part of updating vcpu model out of kvm_update_cpuid(), and put
>>> it into a new kvm_update_vcpu_model(). So it's more clear that
>>> kvm_update_cpuid() is to update guest CPUID settings, while
>>> kvm_update_vcpu_model() is to update vcpu model (settings) based on the
>>> updated CPUID settings.
>>>
>>> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
>>
>> I would prefer to keep the kvm_update_cpuid name for what you called
>> kvm_update_vcpu_model(), and rename the rest to
>> kvm_update_cpuid_runtime().
>
> But there is no CPUID being updated in kvm_update_cpuid(), after
> kvm_update_cpuid_runtime() is split out. This is confusing, IMO.

Then what about kvm_vcpu_after_set_cpuid()? It's the "model" that is
not clear.

Thanks,

Paolo

>> Paolo
>>
>>> ---
>>>   arch/x86/kvm/cpuid.c | 38 ++++++++++++++++++++++++--------------
>>>   arch/x86/kvm/cpuid.h |  1 +
>>>   arch/x86/kvm/x86.c   |  1 +
>>>   3 files changed, 26 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
>>> index a825878b7f84..001f5a94880e 100644
>>> --- a/arch/x86/kvm/cpuid.c
>>> +++ b/arch/x86/kvm/cpuid.c
>>> @@ -76,7 +76,6 @@ static int kvm_check_cpuid(struct kvm_vcpu *vcpu)
>>>   void kvm_update_cpuid(struct kvm_vcpu *vcpu)
>>>   {
>>>       struct kvm_cpuid_entry2 *best;
>>> -    struct kvm_lapic *apic = vcpu->arch.apic;
>>>         best = kvm_find_cpuid_entry(vcpu, 1, 0);
>>>       if (best) {
>>> @@ -89,26 +88,14 @@ void kvm_update_cpuid(struct kvm_vcpu *vcpu)
>>>                  vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE);
>>>       }
>>>   -    if (best && apic) {
>>> -        if (cpuid_entry_has(best, X86_FEATURE_TSC_DEADLINE_TIMER))
>>> -            apic->lapic_timer.timer_mode_mask = 3 << 17;
>>> -        else
>>> -            apic->lapic_timer.timer_mode_mask = 1 << 17;
>>> -    }
>>> -
>>>       best = kvm_find_cpuid_entry(vcpu, 7, 0);
>>>       if (best && boot_cpu_has(X86_FEATURE_PKU) && best->function ==
>>> 0x7)
>>>           cpuid_entry_change(best, X86_FEATURE_OSPKE,
>>>                      kvm_read_cr4_bits(vcpu, X86_CR4_PKE));
>>>         best = kvm_find_cpuid_entry(vcpu, 0xD, 0);
>>> -    if (!best) {
>>> -        vcpu->arch.guest_supported_xcr0 = 0;
>>> -    } else {
>>> -        vcpu->arch.guest_supported_xcr0 =
>>> -            (best->eax | ((u64)best->edx << 32)) & supported_xcr0;
>>> +    if (best)
>>>           best->ebx = xstate_required_size(vcpu->arch.xcr0, false);
>>> -    }
>>>         best = kvm_find_cpuid_entry(vcpu, 0xD, 1);
>>>       if (best && (cpuid_entry_has(best, X86_FEATURE_XSAVES) ||
>>> @@ -127,6 +114,27 @@ void kvm_update_cpuid(struct kvm_vcpu *vcpu)
>>>                          vcpu->arch.ia32_misc_enable_msr &
>>>                          MSR_IA32_MISC_ENABLE_MWAIT);
>>>       }
>>> +}
>>> +
>>> +void kvm_update_vcpu_model(struct kvm_vcpu *vcpu)
>>> +{
>>> +    struct kvm_lapic *apic = vcpu->arch.apic;
>>> +    struct kvm_cpuid_entry2 *best;
>>> +
>>> +    best = kvm_find_cpuid_entry(vcpu, 1, 0);
>>> +    if (best && apic) {
>>> +        if (cpuid_entry_has(best, X86_FEATURE_TSC_DEADLINE_TIMER))
>>> +            apic->lapic_timer.timer_mode_mask = 3 << 17;
>>> +        else
>>> +            apic->lapic_timer.timer_mode_mask = 1 << 17;
>>> +    }
>>> +
>>> +    best = kvm_find_cpuid_entry(vcpu, 0xD, 0);
>>> +    if (!best)
>>> +        vcpu->arch.guest_supported_xcr0 = 0;
>>> +    else
>>> +        vcpu->arch.guest_supported_xcr0 =
>>> +            (best->eax | ((u64)best->edx << 32)) & supported_xcr0;
>>>         /* Note, maxphyaddr must be updated before tdp_level. */
>>>       vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
>>> @@ -218,6 +226,7 @@ int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
>>>       kvm_apic_set_version(vcpu);
>>>       kvm_x86_ops.cpuid_update(vcpu);
>>>       kvm_update_cpuid(vcpu);
>>> +    kvm_update_vcpu_model(vcpu);
>>>         kvfree(cpuid_entries);
>>>   out:
>>> @@ -247,6 +256,7 @@ int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
>>>       kvm_apic_set_version(vcpu);
>>>       kvm_x86_ops.cpuid_update(vcpu);
>>>       kvm_update_cpuid(vcpu);
>>> +    kvm_update_vcpu_model(vcpu);
>>>   out:
>>>       return r;
>>>   }
>>> diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
>>> index f136de1debad..45e3643e2fba 100644
>>> --- a/arch/x86/kvm/cpuid.h
>>> +++ b/arch/x86/kvm/cpuid.h
>>> @@ -10,6 +10,7 @@ extern u32 kvm_cpu_caps[NCAPINTS] __read_mostly;
>>>   void kvm_set_cpu_caps(void);
>>>     void kvm_update_cpuid(struct kvm_vcpu *vcpu);
>>> +void kvm_update_vcpu_model(struct kvm_vcpu *vcpu);
>>>   struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
>>>                             u32 function, u32 index);
>>>   int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
>>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>>> index 09ee54f5e385..6f376392e6e6 100644
>>> --- a/arch/x86/kvm/x86.c
>>> +++ b/arch/x86/kvm/x86.c
>>> @@ -8184,6 +8184,7 @@ static void enter_smm(struct kvm_vcpu *vcpu)
>>>   #endif
>>>         kvm_update_cpuid(vcpu);
>>> +    kvm_update_vcpu_model(vcpu);
>>>       kvm_mmu_reset_context(vcpu);
>>>   }
>>>  
>>
>

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