[v4,05/13] memory: Introduce PrivateSharedManager Interface as child of GenericStateManager

Commit Message

Chenyi Qiang April 7, 2025, 7:49 a.m. UTC

To manage the private and shared RAM states in confidential VMs,
introduce a new class of PrivateShareManager as a child of
GenericStateManager, which inherits the six interface callbacks. With a
different interface type, it can be distinguished from the
RamDiscardManager object and provide the flexibility for addressing
specific requirements of confidential VMs in the future.

Signed-off-by: Chenyi Qiang <[e-mail]>
---
Changes in v4:
    - Newly added.
---
 include/exec/memory.h | 44 +++++++++++++++++++++++++++++++++++++++++--
 system/memory.c       | 17 +++++++++++++++++
 2 files changed, 59 insertions(+), 2 deletions(-)

Patch

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 30e5838d02..08f25e5e84 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -55,6 +55,12 @@  typedef struct RamDiscardManager RamDiscardManager;
 DECLARE_OBJ_CHECKERS(RamDiscardManager, RamDiscardManagerClass,
                      RAM_DISCARD_MANAGER, TYPE_RAM_DISCARD_MANAGER);
 
+#define TYPE_PRIVATE_SHARED_MANAGER "private-shared-manager"
+typedef struct PrivateSharedManagerClass PrivateSharedManagerClass;
+typedef struct PrivateSharedManager PrivateSharedManager;
+DECLARE_OBJ_CHECKERS(PrivateSharedManager, PrivateSharedManagerClass,
+                     PRIVATE_SHARED_MANAGER, TYPE_PRIVATE_SHARED_MANAGER)
+
 #ifdef CONFIG_FUZZ
 void fuzz_dma_read_cb(size_t addr,
                       size_t len,
@@ -692,6 +698,14 @@  void generic_state_manager_register_listener(GenericStateManager *gsm,
 void generic_state_manager_unregister_listener(GenericStateManager *gsm,
                                                StateChangeListener *scl);
 
+static inline void state_change_listener_init(StateChangeListener *scl,
+                                              NotifyStateSet state_set_fn,
+                                              NotifyStateClear state_clear_fn)
+{
+    scl->notify_to_state_set = state_set_fn;
+    scl->notify_to_state_clear = state_clear_fn;
+}
+
 typedef struct RamDiscardListener RamDiscardListener;
 
 struct RamDiscardListener {
@@ -713,8 +727,7 @@  static inline void ram_discard_listener_init(RamDiscardListener *rdl,
                                              NotifyStateClear discard_fn,
                                              bool double_discard_supported)
 {
-    rdl->scl.notify_to_state_set = populate_fn;
-    rdl->scl.notify_to_state_clear = discard_fn;
+    state_change_listener_init(&rdl->scl, populate_fn, discard_fn);
     rdl->double_discard_supported = double_discard_supported;
 }
 
@@ -757,6 +770,25 @@  struct RamDiscardManagerClass {
     GenericStateManagerClass parent_class;
 };
 
+typedef struct PrivateSharedListener PrivateSharedListener;
+struct PrivateSharedListener {
+    struct StateChangeListener scl;
+
+    QLIST_ENTRY(PrivateSharedListener) next;
+};
+
+struct PrivateSharedManagerClass {
+    /* private */
+    GenericStateManagerClass parent_class;
+};
+
+static inline void private_shared_listener_init(PrivateSharedListener *psl,
+                                                NotifyStateSet populate_fn,
+                                                NotifyStateClear discard_fn)
+{
+    state_change_listener_init(&psl->scl, populate_fn, discard_fn);
+}
+
 /**
  * memory_get_xlat_addr: Extract addresses from a TLB entry
  *
@@ -2521,6 +2553,14 @@  int memory_region_set_generic_state_manager(MemoryRegion *mr,
  */
 bool memory_region_has_ram_discard_manager(MemoryRegion *mr);
 
+/**
+ * memory_region_has_private_shared_manager: check whether a #MemoryRegion has a
+ * #PrivateSharedManager assigned
+ *
+ * @mr: the #MemoryRegion
+ */
+bool memory_region_has_private_shared_manager(MemoryRegion *mr);
+
 /**
  * memory_region_find: translate an address/size relative to a
  * MemoryRegion into a #MemoryRegionSection.
diff --git a/system/memory.c b/system/memory.c
index 7b921c66a6..e6e944d9c0 100644
--- a/system/memory.c
+++ b/system/memory.c
@@ -2137,6 +2137,16 @@  bool memory_region_has_ram_discard_manager(MemoryRegion *mr)
     return true;
 }
 
+bool memory_region_has_private_shared_manager(MemoryRegion *mr)
+{
+    if (!memory_region_is_ram(mr) ||
+        !object_dynamic_cast(OBJECT(mr->gsm), TYPE_PRIVATE_SHARED_MANAGER)) {
+        return false;
+    }
+
+    return true;
+}
+
 uint64_t generic_state_manager_get_min_granularity(const GenericStateManager *gsm,
                                                    const MemoryRegion *mr)
 {
@@ -3837,12 +3847,19 @@  static const TypeInfo ram_discard_manager_info = {
     .class_size         = sizeof(RamDiscardManagerClass),
 };
 
+static const TypeInfo private_shared_manager_info = {
+    .parent             = TYPE_GENERIC_STATE_MANAGER,
+    .name               = TYPE_PRIVATE_SHARED_MANAGER,
+    .class_size         = sizeof(PrivateSharedManagerClass),
+};
+
 static void memory_register_types(void)
 {
     type_register_static(&memory_region_info);
     type_register_static(&iommu_memory_region_info);
     type_register_static(&generic_state_manager_info);
     type_register_static(&ram_discard_manager_info);
+    type_register_static(&private_shared_manager_info);
 }
 
 type_init(memory_register_types)