linux-kernel - Re: [PATCH] KVM: Remove unnecessary export of kvm_{inc,dec}_notifier

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Date:   Mon, 6 Sep 2021 12:21:41 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Maxim Levitsky <mlevitsk@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] KVM: Remove unnecessary export of
 kvm_{inc,dec}_notifier_count()

On 05/09/21 09:12, Maxim Levitsky wrote:
> On Thu, 2021-09-02 at 10:59 -0700, Sean Christopherson wrote:
>> Don't export KVM's MMU notifier count helpers, under no circumstance
>> should any downstream module, including x86's vendor code, have a
>> legitimate reason to piggyback KVM's MMU notifier logic.  E.g in the x86
>> case, only KVM's MMU should be elevating the notifier count, and that
>> code is always built into the core kvm.ko module.
>>
>> Fixes: edb298c663fc ("KVM: x86/mmu: bump mmu notifier count in kvm_zap_gfn_range")
>> Cc: Maxim Levitsky <mlevitsk@...hat.com>
>> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
>> ---
>>   virt/kvm/kvm_main.c | 3 ---
>>   1 file changed, 3 deletions(-)
>>
>> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
>> index 3e67c93ca403..140c7d311021 100644
>> --- a/virt/kvm/kvm_main.c
>> +++ b/virt/kvm/kvm_main.c
>> @@ -638,7 +638,6 @@ void kvm_inc_notifier_count(struct kvm *kvm, unsigned long start,
>>   			max(kvm->mmu_notifier_range_end, end);
>>   	}
>>   }
>> -EXPORT_SYMBOL_GPL(kvm_inc_notifier_count);
>>   
>>   static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
>>   					const struct mmu_notifier_range *range)
>> @@ -690,8 +689,6 @@ void kvm_dec_notifier_count(struct kvm *kvm, unsigned long start,
>>   	 */
>>   	kvm->mmu_notifier_count--;
>>   }
>> -EXPORT_SYMBOL_GPL(kvm_dec_notifier_count);
>> -
>>   
>>   static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
>>   					const struct mmu_notifier_range *range)
> 
> Ah, I somehow thought when I wrote this that those two will be used by kvm_amd.
> 
> Reviewed-by: Maxim Levitsky <mlevitsk@...hat.com>
> 
> Best regards,
> 	Maxim Levitsky
> 

Queued, thanks.

Paolo