Re: [PATCH v3 2/6] KVM: x86: Move declaration of kvm_cpu_dirty_log_size() to kvm_dirty_ring.h

[Marc Zyngier <maz@kernel.org>]

On Thu, 22 Sep 2022 01:32:10 +0100,
Gavin Shan <gshan@redhat.com> wrote:
> 
> Not all architectures like ARM64 need to override the function. Move
> its declaration to kvm_dirty_ring.h to avoid the following compiling
> warning on ARM64 when the feature is enabled.
> 
>   arch/arm64/kvm/../../../virt/kvm/dirty_ring.c:14:12:        \
>   warning: no previous prototype for 'kvm_cpu_dirty_log_size' \
>   [-Wmissing-prototypes]                                      \
>   int __weak kvm_cpu_dirty_log_size(void)
>
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> ---
>  arch/x86/include/asm/kvm_host.h | 2 --
>  arch/x86/kvm/mmu/mmu.c          | 2 ++
>  include/linux/kvm_dirty_ring.h  | 1 +
>  3 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 2c96c43c313a..4c0fd517282b 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -2082,8 +2082,6 @@ static inline int kvm_cpu_get_apicid(int mps_cpu)
>  #define GET_SMSTATE(type, buf, offset)		\
>  	(*(type *)((buf) + (offset) - 0x7e00))
>  
> -int kvm_cpu_dirty_log_size(void);
> -
>  int memslot_rmap_alloc(struct kvm_memory_slot *slot, unsigned long npages);
>  
>  #define KVM_CLOCK_VALID_FLAGS						\
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index e418ef3ecfcb..b3eb6a3627ec 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -1349,10 +1349,12 @@ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
>  		kvm_mmu_write_protect_pt_masked(kvm, slot, gfn_offset, mask);
>  }
>  
> +#ifdef CONFIG_HAVE_KVM_DIRTY_RING

I think you can drop the ifdeffery, as HAVE_KVM_DIRTY_RING is
unconditionally selected by the arch Kconfig.

>  int kvm_cpu_dirty_log_size(void)
>  {
>  	return kvm_x86_ops.cpu_dirty_log_size;
>  }
> +#endif
>  
>  bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
>  				    struct kvm_memory_slot *slot, u64 gfn,
> diff --git a/include/linux/kvm_dirty_ring.h b/include/linux/kvm_dirty_ring.h
> index 906f899813dc..8c6755981c9b 100644
> --- a/include/linux/kvm_dirty_ring.h
> +++ b/include/linux/kvm_dirty_ring.h
> @@ -71,6 +71,7 @@ static inline bool kvm_dirty_ring_soft_full(struct kvm_dirty_ring *ring)
>  
>  #else /* CONFIG_HAVE_KVM_DIRTY_RING */
>  
> +int kvm_cpu_dirty_log_size(void);
>  u32 kvm_dirty_ring_get_rsvd_entries(void);
>  int kvm_dirty_ring_alloc(struct kvm_dirty_ring *ring, int index, u32 size);

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.