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From: Paolo Bonzini <pbonzini@redhat.com>
To: "Toralf Förster" <toralf.foerster@gmx.de>
Cc: kvm@vger.kernel.org
Subject: Re: [PATCH] arch/x86/kvm/x86.c: remove a superfluous test for !X86_64
Date: Mon, 28 Apr 2014 10:41:42 +0200	[thread overview]
Message-ID: <535E1446.5020301@redhat.com> (raw)
In-Reply-To: <535D37DE.5050303@gmx.de>

Il 27/04/2014 19:01, Toralf Förster ha scritto:
> On 04/27/2014 05:40 PM, Paolo Bonzini wrote:
>> Il 27/04/2014 17:32, Toralf Förster ha scritto:
>>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>>> index 8b8fc0b..a6ca7e0 100644
>>> --- a/arch/x86/kvm/x86.c
>>> +++ b/arch/x86/kvm/x86.c
>>> @@ -5680,15 +5680,17 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
>>>      kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);
>>>      longmode = is_long_mode(vcpu) && cs_l == 1;
>>>
>>> +#ifdef CONFIG_X86_64
>>>      if (!longmode) {
>>> +#endif
>>
>> This is ugly...
> +1
>
>>
>>>          param = ((u64)kvm_register_read(vcpu, VCPU_REGS_RDX) << 32) |
>>>              (kvm_register_read(vcpu, VCPU_REGS_RAX) & 0xffffffff);
>>>          ingpa = ((u64)kvm_register_read(vcpu, VCPU_REGS_RBX) << 32) |
>>>              (kvm_register_read(vcpu, VCPU_REGS_RCX) & 0xffffffff);
>>>          outgpa = ((u64)kvm_register_read(vcpu, VCPU_REGS_RDI) << 32) |
>>>              (kvm_register_read(vcpu, VCPU_REGS_RSI) & 0xffffffff);
>>> -    }
>>>  #ifdef CONFIG_X86_64
>>
>> ... can you just remove this #ifdef instead?  It will be dead code, but
>> the compiler will detect it as such and remove it.
>>
>
> ok, but VCPU_REGS_R8 is #ifdef'ed in arch/x86/include/asm/kvm_host.h around line 120 and therefore I get :
>
> tfoerste@n22 ~/devel/linux $ sudo make modules
> ...
>   CHK     include/config/kernel.release
>   CHK     include/generated/uapi/linux/version.h
>   CHK     include/generated/utsrelease.h
>   CALL    scripts/checksyscalls.sh
>   CC [M]  arch/x86/kvm/x86.o
> arch/x86/kvm/x86.c: In function ‘kvm_hv_hypercall’:
> arch/x86/kvm/x86.c:5694:36: error: ‘VCPU_REGS_R8’ undeclared (first use in this function)
> arch/x86/kvm/x86.c:5694:36: note: each undeclared identifier is reported only once for each function it appears in
> make[2]: *** [arch/x86/kvm/x86.o] Error 1
> make[1]: *** [arch/x86/kvm] Error 2
> make: *** [arch/x86] Error 2

You can just BUG() in the #else then if you really feel like fixing this:

	} else {
#ifdef CONFIG_X86_64
		...
#else
		BUG();
#endif

Paolo

>
>> Paolo
>>
>>> +    }
>>>      else {
>>>          param = kvm_register_read(vcpu, VCPU_REGS_RCX);
>>>          ingpa = kvm_register_read(vcpu, VCPU_REGS_RDX);
>>
>>
>
>


      reply	other threads:[~2014-04-28  8:41 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-27 15:32 [PATCH] arch/x86/kvm/x86.c: remove a superfluous test for !X86_64 Toralf Förster
2014-04-27 15:40 ` Paolo Bonzini
2014-04-27 17:01   ` Toralf Förster
2014-04-28  8:41     ` Paolo Bonzini [this message]

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