if (mem->flags & KVM_MEM_GUEST_MEMFD)
valid_flags &= ~KVM_MEM_LOG_DIRTY_PAGES;
-#ifdef __KVM_HAVE_READONLY_MEM
+#ifdef CONFIG_HAVE_KVM_READONLY_MEM
- valid_flags |= KVM_MEM_READONLY;
+ /*
+ * GUEST_MEMFD is incompatible with read-only memslots, as writes to
+ * read-only memslots have emulated MMIO, not page fault, semantics,
+ * and KVM doesn't allow emulated MMIO for private memory.
+ */
+ if (!(mem->flags & KVM_MEM_GUEST_MEMFD))
+ valid_flags |= KVM_MEM_READONLY;
#endif
if (mem->flags & ~valid_flags)