* Re: [PATCH] KVM: x86: avoid warning with -Wbitwise-instead-of-logical [not found] <20211015085148.67943-1-pbonzini@redhat.com> @ 2021-10-15 16:37 ` Nathan Chancellor 2021-10-15 17:46 ` Nick Desaulniers 0 siblings, 1 reply; 2+ messages in thread From: Nathan Chancellor @ 2021-10-15 16:37 UTC (permalink / raw) To: Paolo Bonzini; +Cc: linux-kernel, kvm, seanjc, torvic9, Jim Mattson, llvm On Fri, Oct 15, 2021 at 04:51:48AM -0400, Paolo Bonzini wrote: > This is a new warning in clang top-of-tree (will be clang 14): > > In file included from arch/x86/kvm/mmu/mmu.c:27: > arch/x86/kvm/mmu/spte.h:318:9: error: use of bitwise '|' with boolean operands [-Werror,-Wbitwise-instead-of-logical] > return __is_bad_mt_xwr(rsvd_check, spte) | > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > || > arch/x86/kvm/mmu/spte.h:318:9: note: cast one or both operands to int to silence this warning > > Reported-by: torvic9@mailbox.org > Suggested-by: Jim Mattson <jmattson@google.com> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> > --- > arch/x86/kvm/mmu/spte.h | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h > index eb7b227fc6cf..32bc7268c9ea 100644 > --- a/arch/x86/kvm/mmu/spte.h > +++ b/arch/x86/kvm/mmu/spte.h > @@ -314,9 +314,12 @@ static __always_inline bool is_rsvd_spte(struct rsvd_bits_validate *rsvd_check, > * Use a bitwise-OR instead of a logical-OR to aggregate the reserved > * bits and EPT's invalid memtype/XWR checks to avoid an extra Jcc > * (this is extremely unlikely to be short-circuited as true). > + * > + * (int) avoids clang's "use of bitwise '|' with boolean operands" > + * warning. > */ > - return __is_bad_mt_xwr(rsvd_check, spte) | > - __is_rsvd_bits_set(rsvd_check, spte, level); > + return (int)__is_bad_mt_xwr(rsvd_check, spte) | > + (int)__is_rsvd_bits_set(rsvd_check, spte, level); > } > > static inline bool spte_can_locklessly_be_made_writable(u64 spte) > -- > 2.27.0 > > ^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] KVM: x86: avoid warning with -Wbitwise-instead-of-logical 2021-10-15 16:37 ` [PATCH] KVM: x86: avoid warning with -Wbitwise-instead-of-logical Nathan Chancellor @ 2021-10-15 17:46 ` Nick Desaulniers 0 siblings, 0 replies; 2+ messages in thread From: Nick Desaulniers @ 2021-10-15 17:46 UTC (permalink / raw) To: Nathan Chancellor Cc: Paolo Bonzini, linux-kernel, kvm, seanjc, torvic9, Jim Mattson, llvm On Fri, Oct 15, 2021 at 9:37 AM Nathan Chancellor <nathan@kernel.org> wrote: > > On Fri, Oct 15, 2021 at 04:51:48AM -0400, Paolo Bonzini wrote: > > This is a new warning in clang top-of-tree (will be clang 14): > > > > In file included from arch/x86/kvm/mmu/mmu.c:27: > > arch/x86/kvm/mmu/spte.h:318:9: error: use of bitwise '|' with boolean operands [-Werror,-Wbitwise-instead-of-logical] > > return __is_bad_mt_xwr(rsvd_check, spte) | > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > || > > arch/x86/kvm/mmu/spte.h:318:9: note: cast one or both operands to int to silence this warning > > > > Reported-by: torvic9@mailbox.org > > Suggested-by: Jim Mattson <jmattson@google.com> > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > > Reviewed-by: Nathan Chancellor <nathan@kernel.org> Link: https://github.com/ClangBuiltLinux/linux/issues/1474 Acked-by: Nick Desaulniers <ndesaulniers@google.com> > > > --- > > arch/x86/kvm/mmu/spte.h | 7 +++++-- > > 1 file changed, 5 insertions(+), 2 deletions(-) > > > > diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h > > index eb7b227fc6cf..32bc7268c9ea 100644 > > --- a/arch/x86/kvm/mmu/spte.h > > +++ b/arch/x86/kvm/mmu/spte.h > > @@ -314,9 +314,12 @@ static __always_inline bool is_rsvd_spte(struct rsvd_bits_validate *rsvd_check, > > * Use a bitwise-OR instead of a logical-OR to aggregate the reserved > > * bits and EPT's invalid memtype/XWR checks to avoid an extra Jcc > > * (this is extremely unlikely to be short-circuited as true). > > + * > > + * (int) avoids clang's "use of bitwise '|' with boolean operands" > > + * warning. > > */ > > - return __is_bad_mt_xwr(rsvd_check, spte) | > > - __is_rsvd_bits_set(rsvd_check, spte, level); > > + return (int)__is_bad_mt_xwr(rsvd_check, spte) | > > + (int)__is_rsvd_bits_set(rsvd_check, spte, level); > > } > > > > static inline bool spte_can_locklessly_be_made_writable(u64 spte) > > -- > > 2.27.0 > > > > > -- Thanks, ~Nick Desaulniers ^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-10-15 16:37 ` [PATCH] KVM: x86: avoid warning with -Wbitwise-instead-of-logical Nathan Chancellor
2021-10-15 17:46 ` Nick Desaulniers
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