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Subject: Re: [PATCH v5 1/2] KVM: X86: Introduce handle_ud()
To:     Paolo Bonzini <pbonzini@redhat.com>,
        Wanpeng Li <kernellwp@gmail.com>, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org
Cc:     =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        Andrew Cooper <andrew.cooper3@citrix.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Liran Alon <liran.alon@oracle.com>
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From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat GmbH
Message-ID: <e6c4379c-2038-93c2-99d4-51a45cb9b371@redhat.com>
Date:   Wed, 4 Apr 2018 19:43:19 +0200
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On 04.04.2018 19:12, Paolo Bonzini wrote:
> On 04/04/2018 13:54, David Hildenbrand wrote:
>>> +{
>>> +	enum emulation_result er;
>>> +
>>> +	er = emulate_instruction(vcpu, EMULTYPE_TRAP_UD);
>>> +	if (er == EMULATE_USER_EXIT)
>>> +		return 0;
>>> +	if (er != EMULATE_DONE)
>>> +		kvm_queue_exception(vcpu, UD_VECTOR);
>>> +	return 1;
>> I would now actually prefer
>>
>> if (er == EMULATE_DONE)
>> 	return 1 ...
> 
> Why?  The return statement would be duplicated.
> 
> Paolo
> 

I was talking about two equality checks vs. 1 equality and 1 inequality
check.

er = emulate_instruction(vcpu, EMULTYPE_TRAP_UD);
if (er == EMULATE_USER_EXIT)
	return 0;
else if (er == EMULATE_DONE)
	return 1;
return kvm_queue_exception(vcpu, UD_VECTOR);


-- 

Thanks,

David / dhildenb