Re: [BUG] [5.15] Compilation error in arch/x86/kvm/mmu/spte.h with clang-14

[Paolo Bonzini]

On 04/10/21 11:30, torvic9@xxxxxxxxxxx wrote:
> > Paolo Bonzini <pbonzini@xxxxxxxxxx> hat am 04.10.2021 11:26 geschrieben:
> >
> >   
> > On 04/10/21 11:08, torvic9@xxxxxxxxxxx wrote:
> > > I encounter the following issue when compiling 5.15-rc4 with 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
> >
> > The warning is wrong, as mentioned in the line right above:
>
> So it's an issue with clang-14 then?
> (I add Nick and Nathan)

My clang here doesn't have the option, so I'm going to ask---are you 
using W=1?  I can see why clang is warning for KVM's code, but in my 
opinion such a check should only be in -Wextra.

Paolo

> >           /*
> >            * 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).
> >            */
> >
> > Paolo