Hi Wanpeng,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on kvm/linux-next]
[also build test ERROR on v4.18-rc4 next-20180709]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Wanpeng-Li/KVM-Add-coalesced-PIO-support/20180710-182037
base:   https://git.kernel.org/pub/scm/virt/kvm/kvm.git linux-next
config: i386-randconfig-x075-201827 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-16) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

   arch/x86/kvm/../../../virt/kvm/kvm_main.c: In function 'kvm_vm_ioctl_check_extension_generic':
>> arch/x86/kvm/../../../virt/kvm/kvm_main.c:2939:7: error: 'KVM_CAP_COALESCED_PIO' undeclared (first use in this function); did you mean 'KVM_CAP_COALESCED_MMIO'?
     case KVM_CAP_COALESCED_PIO:
          ^~~~~~~~~~~~~~~~~~~~~
          KVM_CAP_COALESCED_MMIO
   arch/x86/kvm/../../../virt/kvm/kvm_main.c:2939:7: note: each undeclared identifier is reported only once for each function it appears in

vim +2939 arch/x86/kvm/../../../virt/kvm/kvm_main.c

  2918	
  2919	static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
  2920	{
  2921		switch (arg) {
  2922		case KVM_CAP_USER_MEMORY:
  2923		case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
  2924		case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS:
  2925		case KVM_CAP_INTERNAL_ERROR_DATA:
  2926	#ifdef CONFIG_HAVE_KVM_MSI
  2927		case KVM_CAP_SIGNAL_MSI:
  2928	#endif
  2929	#ifdef CONFIG_HAVE_KVM_IRQFD
  2930		case KVM_CAP_IRQFD:
  2931		case KVM_CAP_IRQFD_RESAMPLE:
  2932	#endif
  2933		case KVM_CAP_IOEVENTFD_ANY_LENGTH:
  2934		case KVM_CAP_CHECK_EXTENSION_VM:
  2935			return 1;
  2936	#ifdef CONFIG_KVM_MMIO
  2937		case KVM_CAP_COALESCED_MMIO:
  2938			return KVM_COALESCED_MMIO_PAGE_OFFSET;
> 2939		case KVM_CAP_COALESCED_PIO:
  2940			return KVM_PIO_PAGE_OFFSET;
  2941	#endif
  2942	#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
  2943		case KVM_CAP_IRQ_ROUTING:
  2944			return KVM_MAX_IRQ_ROUTES;
  2945	#endif
  2946	#if KVM_ADDRESS_SPACE_NUM > 1
  2947		case KVM_CAP_MULTI_ADDRESS_SPACE:
  2948			return KVM_ADDRESS_SPACE_NUM;
  2949	#endif
  2950		case KVM_CAP_MAX_VCPU_ID:
  2951			return KVM_MAX_VCPU_ID;
  2952		default:
  2953			break;
  2954		}
  2955		return kvm_vm_ioctl_check_extension(kvm, arg);
  2956	}
  2957	

---
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