+ bool
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index 47a9f68f7b24..9ee162bf6bde 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -307,7 +307,78 @@ static pgoff_t kvm_gmem_get_index(struct kvm_memory_slot *slot, gfn_t gfn)
return gfn - slot->base_gfn + slot->gmem.pgoff;
}
+#ifdef CONFIG_KVM_GMEM_MAPPABLE
+static vm_fault_t kvm_gmem_fault(struct vm_fault *vmf)
+{
+ struct inode *inode = file_inode(vmf->vma->vm_file);
+ struct folio *folio;
+ vm_fault_t ret = VM_FAULT_LOCKED;
+
+ filemap_invalidate_lock_shared(inode->i_mapping);
+
+ folio = kvm_gmem_get_folio(inode, vmf->pgoff);
Would the idea be later that kvm_gmem_get_folio() would fail on private
memory, or do you envision other checks in this code here in the future?
There would be other checks in the future, the idea is that they would
be the ones in:
https://lore.kernel.org/all/20250117163001.2326672-8-tabba@xxxxxxxxxx/
Thanks, so I wonder if this patch should just add necessary callback(s)
as well, to make this patch look like it adds most of the infrastructure
on the mmap level.
kvm_gmem_is_shared() or sth like that, documenting that it must be
called after kvm_gmem_get_folio() -- with a raised folio reference /
folio lock.
Alternatively, provide a
kvm_gmem_get_shared_folio()
that abstracts that operation.
We could also for now ensure that we really only get small folios back,
and even get rid of the clearing loop.
The "WARN_ON_ONCE(folio_test_guestmem(folio)" would be added separately.
In the context of this series, the callback would be a nop and always
say "yes".
--
Cheers,
David / dhildenb
