linux-kernel - Re: [PATCH] KVM: X86: correct meaningless kvm_apicv

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Message-ID: <87zhcgl2xc.fsf@vitty.brq.redhat.com>
Date:   Mon, 16 Mar 2020 16:44:47 +0100
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     Sean Christopherson <sean.j.christopherson@...el.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>, linmiaohe@...wei.com,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: Re: [PATCH] KVM: X86: correct meaningless kvm_apicv_activated() check

Sean Christopherson <sean.j.christopherson@...el.com> writes:

> On Mon, Mar 16, 2020 at 09:33:50AM +0100, Vitaly Kuznetsov wrote:
>> Paolo Bonzini <pbonzini@...hat.com> writes:
>> > +	if ((old == 0) == (new == 0))
>> > +		return;
>> 
>> This is a very laconic expression I personally find hard to read :-)
>> 
>> 	/* Check if WE actually changed APICv state */
>>         if ((!old && !new) || (old && new))
>> 		return;
>> 
>> would be my preference (not strong though, I read yours several times
>> and now I feel like I understand it just fine :-)
>
> Or maybe this to avoid so many equals signs?
>
> 	if (!old == !new)
> 		return;
>

	if (!!old == !!new)
		return;

to make it clear we're converting them to 1/0 :-)

-- 
Vitaly