[Zion] Move Memory Mappings to a dedicated tree impl.

zion/lib/memory_mapping_tree.cpp

@@ -0,0 +1,57 @@
+#include "lib/memory_mapping_tree.h"
+
+#include "debug/debug.h"
+
+glcr::ErrorCode MemoryMappingTree::AddInMemoryObject(
+    uint64_t vaddr, const glcr::RefPtr<MemoryObject>& object) {
+  // TODO: This implementation is inefficient as it traverses the tree a lot, we
+  // should have some solution with iterators to avoid this.
+  auto predecessor_or = mapping_tree_.Predecessor(vaddr);
+  if (predecessor_or && predecessor_or.value().get().vaddr_limit > vaddr) {
+    return glcr::ALREADY_EXISTS;
+  }
+  if (mapping_tree_.Find(vaddr)) {
+    return glcr::ALREADY_EXISTS;
+  }
+  auto successor_or = mapping_tree_.Successor(vaddr);
+  if (successor_or &&
+      successor_or.value().get().vaddr_base < vaddr + object->size()) {
+    return glcr::ALREADY_EXISTS;
+  }
+
+  mapping_tree_.Insert(vaddr, MemoryMapping{
+                                  .vaddr_base = vaddr,
+                                  .vaddr_limit = vaddr + object->size(),
+                                  .mem_object = object,
+                              });
+
+  return glcr::OK;
+}
+
+glcr::ErrorCode FreeMemoryRange(uint64_t vaddr_base, uint64_t vaddr_limit) {
+  dbgln("Unhandled free memory range!");
+  return glcr::OK;
+}
+
+glcr::ErrorOr<uint64_t> MemoryMappingTree::GetPhysicalPageAtVaddr(
+    uint64_t vaddr) {
+  auto mapping_or = GetMemoryMappingForAddr(vaddr);
+  if (!mapping_or) {
+    return glcr::NOT_FOUND;
+  }
+  MemoryMapping& mapping = mapping_or.value();
+  return mapping.mem_object->PhysicalPageAtOffset(vaddr - mapping.vaddr_base);
+}
+
+glcr::Optional<glcr::Ref<MemoryMappingTree::MemoryMapping>>
+MemoryMappingTree::GetMemoryMappingForAddr(uint64_t vaddr) {
+  auto mapping_or = mapping_tree_.Predecessor(vaddr + 1);
+  if (!mapping_or) {
+    return mapping_or;
+  }
+  MemoryMapping& mapping = mapping_or.value();
+  if (mapping.vaddr_base + mapping.mem_object->size() <= vaddr) {
+    return {};
+  }
+  return mapping_or;
+}