From: Ackerley Tng <[email protected]> All-shared guest_memfd used to be only supported for non-CoCo VMs where preparation doesn't apply. INIT_SHARED is about to be supported for non-CoCo VMs in a later patch in this series.
In addition, KVM_SET_MEMORY_ATTRIBUTES2 is about to be supported in guest_memfd in a later patch in this series. This means that the kvm fault handler may now call kvm_gmem_get_pfn() on a shared folio for a CoCo VM where preparation applies. Add a check to make sure that preparation is only performed for private folios. Preparation will be undone on freeing (see kvm_gmem_free_folio()) and on conversion to shared. Signed-off-by: Michael Roth <[email protected]> Reviewed-by: Fuad Tabba <[email protected]> Signed-off-by: Ackerley Tng <[email protected]> --- virt/kvm/guest_memfd.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index 78e5435967341..adf57a3a1f5dd 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -894,6 +894,7 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, int *max_order) { pgoff_t index = kvm_gmem_get_index(slot, gfn); + struct inode *inode; struct folio *folio; int r = 0; @@ -901,7 +902,8 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, if (!file) return -EFAULT; - filemap_invalidate_lock_shared(file_inode(file)->i_mapping); + inode = file_inode(file); + filemap_invalidate_lock_shared(inode->i_mapping); folio = __kvm_gmem_get_pfn(file, slot, index, pfn, max_order); if (IS_ERR(folio)) { @@ -914,7 +916,8 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, folio_mark_uptodate(folio); } - r = kvm_gmem_prepare_folio(kvm, slot, gfn, folio); + if (kvm_gmem_is_private_mem(inode, index)) + r = kvm_gmem_prepare_folio(kvm, slot, gfn, folio); folio_unlock(folio); @@ -924,7 +927,7 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, folio_put(folio); out: - filemap_invalidate_unlock_shared(file_inode(file)->i_mapping); + filemap_invalidate_unlock_shared(inode->i_mapping); return r; } EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gmem_get_pfn); -- 2.54.0.794.g4f17f83d09-goog
