Re: [PATCH] KVM: VMX: replace "fall through" with "return true" to indicate different case

[linmiaohe]

Sean Christopherson <sean.j.christopherson@xxxxxxxxx> wrote:
>On Tue, Feb 18, 2020 at 11:39:28AM +0800, linmiaohe wrote:
>> From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
>> 
>> @@ -4495,7 +4495,7 @@ static bool rmode_exception(struct kvm_vcpu *vcpu, int vec)
>>  		if (vcpu->guest_debug &
>>  			(KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP))
>>  			return false;
>> -		/* fall through */
>> +		return true;
>
>I prefer the current code, i.e. the fall through.  This code is already burdened with a fall through, from #BP->#DB, and IMO the fall through makes it more obvious that the vcpu->guest_debug checks are corner cases, while everything else is handled by common logic.

Yeh, it looks better this way. But from a different perspective, "return turn" here indicates #BP and #DB need do vcpu->guest_debug checks, while others not.
Thanks. :)

>
>>  	case DE_VECTOR:
>>  	case OF_VECTOR:
>>  	case BR_VECTOR: