Re: [PATCH v4] kvm: better MWAIT emulation for guests

[kbuild test robot]

Hi Michael,

[auto build test ERROR on kvm/linux-next]
[also build test ERROR on v4.11-rc2 next-20170310]
[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/Michael-S-Tsirkin/kvm-better-MWAIT-emulation-for-guests/20170316-143518
base:   https://git.kernel.org/pub/scm/virt/kvm/kvm.git linux-next
config: x86_64-randconfig-x010-201711 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All error/warnings (new ones prefixed by >>):

   In file included from arch/x86/kvm/x86.c:28:0:
   arch/x86/kvm/x86.h: In function 'kvm_mwait_in_guest':
>> arch/x86/kvm/x86.h:231:34: error: 'CPUID_MWAIT_LEAF' undeclared (first use in this function)
     if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
                                     ^~~~~~~~~~~~~~~~
   arch/x86/kvm/x86.h:231:34: note: each undeclared identifier is reported only once for each function it appears in
>> arch/x86/kvm/x86.h:234:45: error: 'mwait_substates' undeclared (first use in this function)
     cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates);
                                                ^~~~~~~~~~~~~~~
>> arch/x86/kvm/x86.h:236:14: error: 'CPUID5_ECX_INTERRUPT_BREAK' undeclared (first use in this function)
     if (!(ecx & CPUID5_ECX_INTERRUPT_BREAK))
                 ^~~~~~~~~~~~~~~~~~~~~~~~~~
>> arch/x86/kvm/x86.h:238:1: warning: control reaches end of non-void function [-Wreturn-type]
    }
    ^
--
   In file included from arch/x86/kvm/mmu.c:23:0:
   arch/x86/kvm/x86.h: In function 'kvm_mwait_in_guest':
>> arch/x86/kvm/x86.h:231:34: error: 'CPUID_MWAIT_LEAF' undeclared (first use in this function)
     if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
                                     ^~~~~~~~~~~~~~~~
   arch/x86/kvm/x86.h:231:34: note: each undeclared identifier is reported only once for each function it appears in
>> arch/x86/kvm/x86.h:234:45: error: 'mwait_substates' undeclared (first use in this function)
     cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates);
                                                ^~~~~~~~~~~~~~~
>> arch/x86/kvm/x86.h:236:14: error: 'CPUID5_ECX_INTERRUPT_BREAK' undeclared (first use in this function)
     if (!(ecx & CPUID5_ECX_INTERRUPT_BREAK))
                 ^~~~~~~~~~~~~~~~~~~~~~~~~~
   At top level:
   arch/x86/kvm/x86.h:216:13: warning: 'kvm_mwait_in_guest' defined but not used [-Wunused-function]
    static bool kvm_mwait_in_guest(void)
                ^~~~~~~~~~~~~~~~~~

vim +/CPUID_MWAIT_LEAF +231 arch/x86/kvm/x86.h

   225	
   226		/*
   227		 * Intel CPUs without CPUID5_ECX_INTERRUPT_BREAK are problematic as
   228		 * they would allow guest to stop the CPU completely by disabling
   229		 * interrupts then invoking MWAIT.
   230		 */
 > 231		if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
   232			return -ENODEV;
   233	
 > 234		cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates);
   235	
 > 236		if (!(ecx & CPUID5_ECX_INTERRUPT_BREAK))
   237			return -ENODEV;
 > 238	}
   239	
   240	#endif

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0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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