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

[Gavin Shan]

Hi Marc,

On 9/25/22 5:12 AM, Marc Zyngier wrote:

On Thu, 22 Sep 2022 01:32:10 +0100,
Gavin Shan <gs...@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 <l...@intel.com>
Signed-off-by: Gavin Shan <gs...@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.

Yeah, I think so. Lets drop it in v4, which will be rebased on top
of your v2 series.

  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,
Gavin

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