Re: [PATCH v8 42/46] KVM: selftests: Provide common function to set memory attributes

[Fuad Tabba]

On Fri, 19 Jun 2026 at 01:32, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@xxxxxxxxxx> wrote:
>
> From: Sean Christopherson <seanjc@xxxxxxxxxx>
>
> Introduce vm_mem_set_memory_attributes(), which handles setting of memory
> attributes for a range of guest physical addresses, regardless of whether
> the attributes should be set via guest_memfd or via the memory attributes
> at the VM level.
>
> Refactor existing vm_mem_set_{shared,private} functions to use the new
> function. Opportunistically update the size parameter to use size_t instead
> of u64.
>
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> Co-developed-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
> Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>

Reviewed-by: Fuad Tabba <tabba@xxxxxxxxxx>

Cheers,
/fuad

> ---
>  tools/testing/selftests/kvm/include/kvm_util.h | 46 +++++++++++++++++++-------
>  1 file changed, 34 insertions(+), 12 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
> index 3a6b1fa7f26ef..db1442da21bb1 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util.h
> @@ -454,18 +454,6 @@ static inline void vm_set_memory_attributes(struct kvm_vm *vm, gpa_t gpa,
>         vm_ioctl(vm, KVM_SET_MEMORY_ATTRIBUTES, &attr);
>  }
>
> -static inline void vm_mem_set_private(struct kvm_vm *vm, gpa_t gpa,
> -                                     u64 size)
> -{
> -       vm_set_memory_attributes(vm, gpa, size, KVM_MEMORY_ATTRIBUTE_PRIVATE);
> -}
> -
> -static inline void vm_mem_set_shared(struct kvm_vm *vm, gpa_t gpa,
> -                                    u64 size)
> -{
> -       vm_set_memory_attributes(vm, gpa, size, 0);
> -}
> -
>  static inline int __gmem_set_memory_attributes(int fd, u64 offset,
>                                                size_t size, u64 attributes,
>                                                u64 *error_offset)
> @@ -532,6 +520,40 @@ static inline void gmem_set_shared(int fd, u64 offset, size_t size)
>         gmem_set_memory_attributes(fd, offset, size, 0);
>  }
>
> +static inline void vm_mem_set_memory_attributes(struct kvm_vm *vm, gpa_t gpa,
> +                                               size_t size, u64 attrs)
> +{
> +       if (kvm_has_gmem_attributes) {
> +               gpa_t end = gpa + size;
> +               off_t fd_offset;
> +               gpa_t addr;
> +               size_t len;
> +               int fd;
> +
> +               for (addr = gpa; addr < end; addr += len) {
> +                       fd = kvm_gpa_to_guest_memfd(vm, addr, &fd_offset, &len);
> +                       len = min(end - addr, len);
> +
> +                       gmem_set_memory_attributes(fd, fd_offset, len, attrs);
> +               }
> +       } else {
> +               vm_set_memory_attributes(vm, gpa, size, attrs);
> +       }
> +}
> +
> +static inline void vm_mem_set_private(struct kvm_vm *vm, gpa_t gpa,
> +                                     size_t size)
> +{
> +       vm_mem_set_memory_attributes(vm, gpa, size,
> +                                    KVM_MEMORY_ATTRIBUTE_PRIVATE);
> +}
> +
> +static inline void vm_mem_set_shared(struct kvm_vm *vm, gpa_t gpa,
> +                                    size_t size)
> +{
> +       vm_mem_set_memory_attributes(vm, gpa, size, 0);
> +}
> +
>  void vm_guest_mem_fallocate(struct kvm_vm *vm, gpa_t gpa, u64 size,
>                             bool punch_hole);
>
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>