On Wed, Apr 2, 2025 at 9:08 AM Nikita Kalyazin <kalya...@amazon.com> wrote: > > Signed-off-by: Nikita Kalyazin <kalya...@amazon.com> > --- > include/linux/userfaultfd_k.h | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h > index 75342022d144..bc184edfbb85 100644 > --- a/include/linux/userfaultfd_k.h > +++ b/include/linux/userfaultfd_k.h > @@ -212,6 +212,10 @@ static inline bool userfaultfd_armed(struct > vm_area_struct *vma) > return vma->vm_flags & __VM_UFFD_FLAGS; > } > > +#ifdef CONFIG_KVM_PRIVATE_MEM > +bool kvm_gmem_vma_is_gmem(struct vm_area_struct *vma); > +#endif > + > static inline bool vma_can_userfault(struct vm_area_struct *vma, > unsigned long vm_flags, > bool wp_async) > @@ -222,7 +226,11 @@ static inline bool vma_can_userfault(struct > vm_area_struct *vma, > return false; > > if ((vm_flags & VM_UFFD_MINOR) && > - (!is_vm_hugetlb_page(vma) && !vma_is_shmem(vma))) > + (!is_vm_hugetlb_page(vma) && !vma_is_shmem(vma)) > +#ifdef CONFIG_KVM_PRIVATE_MEM > + && !kvm_gmem_vma_is_gmem(vma) > +#endif
Maybe a better way to do this is to add a vm_ops->can_userfault() or something, so we could write something like this: if (vma->vm_ops && !vma->vm_ops->can_userfault) return false; if (vma->vm_ops && !vma->vm_ops->can_userfault(vm_flags)) return false; And shmem/hugetlbfs can advertise support for everything they already support that way. > + ) > return false; > > /* > @@ -244,6 +252,9 @@ static inline bool vma_can_userfault(struct > vm_area_struct *vma, > > /* By default, allow any of anon|shmem|hugetlb */ > return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) || > +#ifdef CONFIG_KVM_PRIVATE_MEM > + kvm_gmem_vma_is_gmem(vma) || > +#endif > vma_is_shmem(vma); > } > > -- > 2.47.1 >
