Hi Yu,

FYI, the error/warning was bisected to this commit, please ignore it if it's irrelevant.

tree: https://gitee.com/openeuler/kernel.git OLK-5.10 head: b32a887db4e5c4c061e61977efabbc1d5e867aa7 commit: 1686d271f795f8756b49151978b95b095c0598ad [27225/30000] KVM: x86: Introduce kvm_post_set_cr0 to post handle the CR0 emulation config: x86_64-buildonly-randconfig-005-20240828 (https://download.01.org/0day-ci/archive/20240828/202408280830.Hi3clUWN-lkp@i...) compiler: gcc-11 (Debian 11.3.0-12) 11.3.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240828/202408280830.Hi3clUWN-lkp@i...)

If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot lkp@intel.com | Closes: https://lore.kernel.org/oe-kbuild-all/202408280830.Hi3clUWN-lkp@intel.com/

All warnings (new ones prefixed by >>):

...

arch/x86/kvm/x86.c:893:6: warning: no previous prototype for 'kvm_post_set_cr0' [-Wmissing-prototypes]

893 | void kvm_post_set_cr0(struct kvm_vcpu *vcpu, unsigned long old_cr0, unsigned long cr0) | ^~~~~~~~~~~~~~~~

vim +/kvm_post_set_cr0 +893 arch/x86/kvm/x86.c

892

893 void kvm_post_set_cr0(struct kvm_vcpu *vcpu, unsigned long old_cr0, unsigned long cr0)

894 { 895 unsigned long update_bits = X86_CR0_PG | X86_CR0_WP; 896 897 if ((cr0 ^ old_cr0) & X86_CR0_PG) { 898 kvm_clear_async_pf_completion_queue(vcpu); 899 kvm_async_pf_hash_reset(vcpu); 900 } 901 902 if ((cr0 ^ old_cr0) & update_bits) 903 kvm_mmu_reset_context(vcpu); 904 905 if (((cr0 ^ old_cr0) & X86_CR0_CD) && 906 kvm_arch_has_noncoherent_dma(vcpu->kvm) && 907 !kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_CD_NW_CLEARED)) 908 kvm_zap_gfn_range(vcpu->kvm, 0, ~0ULL); 909 } 910