On Fri, Jun 18, 2021 at 12:42:56PM +0200, Paolo Bonzini wrote: > On 18/06/21 09:17, kernel test robot wrote: > > Hi David, > > > > Thank you for the patch! Yet something to improve: > > > > [auto build test ERROR on kvm/queue] > > [also build test ERROR on vhost/linux-next v5.13-rc6] > > [If your patch is applied to the wrong git tree, kindly drop us a note. > > And when submitting patch, we suggest to use '--base' as documented in > > https://git-scm.com/docs/git-format-patch] > > > > url:https://github.com/0day-ci/linux/commits/David-Matlack/KVM-x86-mmu-Remove-redundant-is_tdp_mmu_root-check/20210618-082018 > > base:https://git.kernel.org/pub/scm/virt/kvm/kvm.git queue > > config: i386-randconfig-a016-20210618 (attached as .config) > > compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 > > reproduce (this is a W=1 build): > > #https://github.com/0day-ci/linux/commit/6ab060f3cf9061da492b1eb89808eb2da5406781 > > git remote add linux-reviewhttps://github.com/0day-ci/linux > > git fetch --no-tags linux-review David-Matlack/KVM-x86-mmu-Remove-redundant-is_tdp_mmu_root-check/20210618-082018 > > git checkout 6ab060f3cf9061da492b1eb89808eb2da5406781 > > # save the attached .config to linux build tree > > make W=1 ARCH=i386 > > > > If you fix the issue, kindly add following tag as appropriate > > Reported-by: kernel test robot<lkp@xxxxxxxxx> > > > > All errors (new ones prefixed by >>): > > > > ld: arch/x86/kvm/mmu/mmu.o: in function `get_mmio_spte': > > > > arch/x86/kvm/mmu/mmu.c:3612: undefined reference to `kvm_tdp_mmu_get_walk' > > ld: arch/x86/kvm/mmu/mmu.o: in function `direct_page_fault': > > > > arch/x86/kvm/mmu/mmu.c:3830: undefined reference to `kvm_tdp_mmu_map' > > Turns out sometimes is_tdp_mmu_root is not inlined after this patch. > Fixed thusly: Thanks for the fix. I guess after I removed the is_tdp_mmu_enabled() check the compiler couldn't determine what is_tdp_mmu_root() would return on 32-bit builds anymore. Pretty nice of the compiler to throw out kvm_tdp_mmu_get_walk() and kvm_tdp_mmu_map() once it knows they are not reachable so we don't have to implement stubs for those functions that BUG_ON and pray they never get called! > > --------- 8< ----------- > Subject: [PATCH] KVM: x86: Stub out is_tdp_mmu_root on 32-bit hosts > > If is_tdp_mmu_root is not inlined, the elimination of TDP MMU calls as dead > code might not work out. To avoid this, explicitly declare the stubbed > is_tdp_mmu_root on 32-bit hosts. > > Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> > > diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h > index fabfea947e46..f6e0667cf4b6 100644 > --- a/arch/x86/kvm/mmu/tdp_mmu.h > +++ b/arch/x86/kvm/mmu/tdp_mmu.h > @@ -85,12 +85,6 @@ bool kvm_mmu_init_tdp_mmu(struct kvm *kvm); > void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm); > static inline bool is_tdp_mmu_enabled(struct kvm *kvm) { return kvm->arch.tdp_mmu_enabled; } > static inline bool is_tdp_mmu_page(struct kvm_mmu_page *sp) { return sp->tdp_mmu_page; } > -#else > -static inline bool kvm_mmu_init_tdp_mmu(struct kvm *kvm) { return false; } > -static inline void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm) {} > -static inline bool is_tdp_mmu_enabled(struct kvm *kvm) { return false; } > -static inline bool is_tdp_mmu_page(struct kvm_mmu_page *sp) { return false; } > -#endif > static inline bool is_tdp_mmu_root(hpa_t hpa) > { > @@ -105,5 +99,12 @@ static inline bool is_tdp_mmu_root(hpa_t hpa) > return is_tdp_mmu_page(sp) && sp->root_count; > } > +#else > +static inline bool kvm_mmu_init_tdp_mmu(struct kvm *kvm) { return false; } > +static inline void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm) {} > +static inline bool is_tdp_mmu_enabled(struct kvm *kvm) { return false; } > +static inline bool is_tdp_mmu_page(struct kvm_mmu_page *sp) { return false; } > +static inline bool is_tdp_mmu_root(hpa_t hpa) { return false; } > +#endif > #endif /* __KVM_X86_MMU_TDP_MMU_H */ >
