Re: [PATCH] x86: kvm: avoid unused variable warning

From: David Hildenbrand
Date: Wed Aug 22 2018 - 07:51:56 EST


On 20.08.2018 23:37, Arnd Bergmann wrote:
> Removing one of the two accesses of the maxphyaddr variable led to
> a harmless warning:
>
> arch/x86/kvm/x86.c: In function 'kvm_set_mmio_spte_mask':
> arch/x86/kvm/x86.c:6563:6: error: unused variable 'maxphyaddr' [-Werror=unused-variable]
>
> Removing the #ifdef seems to be the nicest workaround, as it
> makes the code look cleaner than adding another #ifdef.
>
> Fixes: 28a1f3ac1d0c ("kvm: x86: Set highest physical address bits in non-present/reserved SPTEs")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> arch/x86/kvm/x86.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 4a74a7cf0a8b..506bd2b4b8bb 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -6576,14 +6576,12 @@ static void kvm_set_mmio_spte_mask(void)
> /* Set the present bit. */
> mask |= 1ull;
>
> -#ifdef CONFIG_X86_64
> /*
> * If reserved bit is not supported, clear the present bit to disable
> * mmio page fault.
> */
> - if (maxphyaddr == 52)
> + if (IS_ENABLED(CONFIG_X86_64) && maxphyaddr == 52)
> mask &= ~1ull;
> -#endif
>
> kvm_mmu_set_mmio_spte_mask(mask, mask);
> }
>

Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>

--

Thanks,

David / dhildenb