Hi Peter,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on vhost/linux-next]
[also build test WARNING on linus/master v5.7-rc7]
[cannot apply to kvm/linux-next tip/auto-latest linux/master next-20200522]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Peter-Xu/KVM-Dirty-ring-interface/20200524-070926
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next
config: s390-randconfig-s002-20200524 (attached as .config)
compiler: s390-linux-gcc (GCC) 9.3.0
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.1-240-gf0fe1cd9-dirty
        # save the attached .config to linux build tree
        make W=1 C=1 ARCH=s390 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__'

If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <lkp@intel.com>

All warnings (new ones prefixed by >>, old ones prefixed by <<):

arch/s390/kvm/../../../virt/kvm/kvm_main.c: In function 'kvm_page_in_dirty_ring':
>> arch/s390/kvm/../../../virt/kvm/kvm_main.c:2932:16: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits]
2932 |  return (pgoff >= KVM_DIRTY_LOG_PAGE_OFFSET) &&
|                ^~

vim +2932 arch/s390/kvm/../../../virt/kvm/kvm_main.c

  2926	
  2927	static bool kvm_page_in_dirty_ring(struct kvm *kvm, unsigned long pgoff)
  2928	{
  2929		if (!KVM_DIRTY_LOG_PAGE_OFFSET)
  2930			return false;
  2931	
> 2932		return (pgoff >= KVM_DIRTY_LOG_PAGE_OFFSET) &&
  2933		    (pgoff < KVM_DIRTY_LOG_PAGE_OFFSET +
  2934		     kvm->dirty_ring_size / PAGE_SIZE);
  2935	}
  2936	

---
0-DAY CI Kernel Test Service, Intel Corporation
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