Re: [PATCH] arch/x86/kvm/x86.c: remove a superfluous test for !X86_64

["Toralf Förster" <toralf.foerster@gmx.de>]

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


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


-- 
Toralf