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

[Paolo Bonzini]

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:

        /*
         * 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