implement simple memory snapshot mechanismus

Uses Copy on Write to make it posible to restore the memory state after a snapshot
was made. To restore all MemoryRegions created after the snapshot are removed.

include/uc_priv.h

@@ -80,6 +80,10 @@ typedef bool (*uc_write_mem_t)(AddressSpace *as, hwaddr addr,
 typedef bool (*uc_read_mem_t)(AddressSpace *as, hwaddr addr, uint8_t *buf,
                               int len);
 
+typedef MemoryRegion* (*uc_mem_cow_t)(struct uc_struct *uc,
+                                      MemoryRegion *current, hwaddr begin,
+                                      size_t size);
+
 typedef void (*uc_args_void_t)(void *);
 
 typedef void (*uc_args_uc_t)(struct uc_struct *);
@@ -102,6 +106,8 @@ typedef void (*uc_mem_unmap_t)(struct uc_struct *, MemoryRegion *mr);
 
 typedef MemoryRegion *(*uc_memory_mapping_t)(struct uc_struct *, hwaddr addr);
 
+typedef void (*uc_memory_filter_t)(MemoryRegion *, int32_t);
+
 typedef void (*uc_readonly_mem_t)(MemoryRegion *mr, bool readonly);
 
 typedef int (*uc_cpus_init)(struct uc_struct *, const char *);
@@ -267,6 +273,7 @@ struct uc_struct {
 
     uc_write_mem_t write_mem;
     uc_read_mem_t read_mem;
+    uc_mem_cow_t memory_cow;
     uc_args_void_t release;  // release resource when uc_close()
     uc_args_uc_u64_t set_pc; // set PC for tracecode
     uc_get_pc_t get_pc;
@@ -280,6 +287,7 @@ struct uc_struct {
     uc_args_uc_ram_size_t memory_map;
     uc_args_uc_ram_size_ptr_t memory_map_ptr;
     uc_memory_mapping_t memory_mapping;
+    uc_memory_filter_t memory_filter_subregions;
     uc_mem_unmap_t memory_unmap;
     uc_readonly_mem_t readonly_mem;
     uc_cpus_init cpus_init;
@@ -403,6 +411,7 @@ struct uc_struct {
     PVOID seh_handle;
     void *seh_closure;
 #endif
+    int32_t snapshot_level;
 };
 
 // Metadata stub for the variable-size cpu context used with uc_context_*()

include/unicorn/unicorn.h

@@ -1345,6 +1345,12 @@ size_t uc_context_size(uc_engine *uc);
 UNICORN_EXPORT
 uc_err uc_context_free(uc_context *context);
 
+UNICORN_EXPORT
+uc_err uc_snapshot(uc_engine *uc);
+
+UNICORN_EXPORT
+uc_err uc_restore_latest_snapshot(uc_engine *uc);
+
 #ifdef __cplusplus
 }
 #endif

qemu/aarch64.h

@@ -123,6 +123,7 @@
 #define memory_map memory_map_aarch64
 #define memory_map_io memory_map_io_aarch64
 #define memory_map_ptr memory_map_ptr_aarch64
+#define memory_cow memory_cow_aarch64
 #define memory_unmap memory_unmap_aarch64
 #define memory_free memory_free_aarch64
 #define flatview_unref flatview_unref_aarch64
@@ -144,6 +145,7 @@
 #define memory_region_del_subregion memory_region_del_subregion_aarch64
 #define memory_region_add_subregion_overlap memory_region_add_subregion_overlap_aarch64
 #define memory_region_find memory_region_find_aarch64
+#define memory_region_filter_subregions memory_region_filter_subregions_aarch64
 #define memory_listener_register memory_listener_register_aarch64
 #define memory_listener_unregister memory_listener_unregister_aarch64
 #define address_space_remove_listeners address_space_remove_listeners_aarch64

qemu/accel/tcg/cputlb.c

@@ -2155,6 +2155,22 @@ store_helper(CPUArchState *env, target_ulong addr, uint64_t val,
         }
     }
 
+    if (uc->snapshot_level && mr->ram && mr->priority < uc->snapshot_level) {
+        mr = memory_cow(uc, mr, addr & TARGET_PAGE_MASK, TARGET_PAGE_SIZE);
+        if (!mr) {
+            uc->invalid_addr = paddr;
+            uc->invalid_error = UC_ERR_NOMEM;
+            cpu_exit(uc->cpu);
+            return;
+        }
+        /* refill tlb after CoW */
+        tlb_fill(env_cpu(env), paddr, size, MMU_DATA_STORE,
+                 mmu_idx, retaddr);
+        index = tlb_index(env, mmu_idx, addr);
+        entry = tlb_entry(env, mmu_idx, addr);
+        tlb_addr = tlb_addr_write(entry);
+    }
+
     /* Handle anything that isn't just a straight memory access.  */
     if (unlikely(tlb_addr & ~TARGET_PAGE_MASK)) {
         CPUIOTLBEntry *iotlbentry;

qemu/arm.h

@@ -123,6 +123,7 @@
 #define memory_map memory_map_arm
 #define memory_map_io memory_map_io_arm
 #define memory_map_ptr memory_map_ptr_arm
+#define memory_cow memory_cow_arm
 #define memory_unmap memory_unmap_arm
 #define memory_free memory_free_arm
 #define flatview_unref flatview_unref_arm
@@ -144,6 +145,7 @@
 #define memory_region_del_subregion memory_region_del_subregion_arm
 #define memory_region_add_subregion_overlap memory_region_add_subregion_overlap_arm
 #define memory_region_find memory_region_find_arm
+#define memory_region_filter_subregions memory_region_filter_subregions_arm
 #define memory_listener_register memory_listener_register_arm
 #define memory_listener_unregister memory_listener_unregister_arm
 #define address_space_remove_listeners address_space_remove_listeners_arm

qemu/include/exec/memory.h

@@ -687,6 +687,35 @@ void memory_region_add_subregion(MemoryRegion *mr,
                                  hwaddr offset,
                                  MemoryRegion *subregion);
 
+/**
+ * memory_region_add_subregion_overlap: Add a subregion to a container
+ *                                      with overlap.
+ *
+ * Adds a subregion at @offset.  The subregion may overlap with other
+ * subregions.  Conflicts are resolved by having a higher @priority hide a
+ * lower @priority. Subregions without priority are taken as @priority 0.
+ * A region may only be added once as a subregion (unless removed with
+ * memory_region_del_subregion()); use memory_region_init_alias() if you
+ * want a region to be a subregion in multiple locations.
+ *
+ * @mr: the region to contain the new subregion; must be a container
+ *      initialized with memory_region_init().
+ * @offset: the offset relative to @mr where @subregion is added.
+ * @subregion: the subregion to be added.
+ * @priority: used for resolving overlaps; highest priority wins.
+ */
+void memory_region_add_subregion_overlap(MemoryRegion *mr,
+                                         hwaddr offset,
+                                         MemoryRegion *subregion,
+                                         int priority);
+
+/**
+ * memory_region_filter_subregions: filter subregios by priority.
+ *
+ * remove all subregions beginning by a specified subregion
+ */
+void memory_region_filter_subregions(MemoryRegion *mr, int32_t level);
+
 /**
  * memory_region_get_ram_addr: Get the ram address associated with a memory
  *                             region

qemu/m68k.h

@@ -123,6 +123,7 @@
 #define memory_map memory_map_m68k
 #define memory_map_io memory_map_io_m68k
 #define memory_map_ptr memory_map_ptr_m68k
+#define memory_cow memory_cow_m68k
 #define memory_unmap memory_unmap_m68k
 #define memory_free memory_free_m68k
 #define flatview_unref flatview_unref_m68k
@@ -144,6 +145,7 @@
 #define memory_region_del_subregion memory_region_del_subregion_m68k
 #define memory_region_add_subregion_overlap memory_region_add_subregion_overlap_m68k
 #define memory_region_find memory_region_find_m68k
+#define memory_region_filter_subregions memory_region_filter_subregions_m68k
 #define memory_listener_register memory_listener_register_m68k
 #define memory_listener_unregister memory_listener_unregister_m68k
 #define address_space_remove_listeners address_space_remove_listeners_m68k

qemu/mips.h

@@ -123,6 +123,7 @@
 #define memory_map memory_map_mips
 #define memory_map_io memory_map_io_mips
 #define memory_map_ptr memory_map_ptr_mips
+#define memory_cow memory_cow_mips
 #define memory_unmap memory_unmap_mips
 #define memory_free memory_free_mips
 #define flatview_unref flatview_unref_mips
@@ -144,6 +145,7 @@
 #define memory_region_del_subregion memory_region_del_subregion_mips
 #define memory_region_add_subregion_overlap memory_region_add_subregion_overlap_mips
 #define memory_region_find memory_region_find_mips
+#define memory_region_filter_subregions memory_region_filter_subregions_mips
 #define memory_listener_register memory_listener_register_mips
 #define memory_listener_unregister memory_listener_unregister_mips
 #define address_space_remove_listeners address_space_remove_listeners_mips

qemu/mips64.h

@@ -123,6 +123,7 @@
 #define memory_map memory_map_mips64
 #define memory_map_io memory_map_io_mips64
 #define memory_map_ptr memory_map_ptr_mips64
+#define memory_cow memory_cow_mips64
 #define memory_unmap memory_unmap_mips64
 #define memory_free memory_free_mips64
 #define flatview_unref flatview_unref_mips64
@@ -144,6 +145,7 @@
 #define memory_region_del_subregion memory_region_del_subregion_mips64
 #define memory_region_add_subregion_overlap memory_region_add_subregion_overlap_mips64
 #define memory_region_find memory_region_find_mips64
+#define memory_region_filter_subregions memory_region_filter_subregions_mips64
 #define memory_listener_register memory_listener_register_mips64
 #define memory_listener_unregister memory_listener_unregister_mips64
 #define address_space_remove_listeners address_space_remove_listeners_mips64

qemu/mips64el.h

@@ -123,6 +123,7 @@
 #define memory_map memory_map_mips64el
 #define memory_map_io memory_map_io_mips64el
 #define memory_map_ptr memory_map_ptr_mips64el
+#define memory_cow memory_cow_mips64el
 #define memory_unmap memory_unmap_mips64el
 #define memory_free memory_free_mips64el
 #define flatview_unref flatview_unref_mips64el
@@ -144,6 +145,7 @@
 #define memory_region_del_subregion memory_region_del_subregion_mips64el
 #define memory_region_add_subregion_overlap memory_region_add_subregion_overlap_mips64el
 #define memory_region_find memory_region_find_mips64el
+#define memory_region_filter_subregions memory_region_filter_subregions_mips64el
 #define memory_listener_register memory_listener_register_mips64el
 #define memory_listener_unregister memory_listener_unregister_mips64el
 #define address_space_remove_listeners address_space_remove_listeners_mips64el

qemu/mipsel.h

@@ -123,6 +123,7 @@
 #define memory_map memory_map_mipsel
 #define memory_map_io memory_map_io_mipsel
 #define memory_map_ptr memory_map_ptr_mipsel
+#define memory_cow memory_cow_mipsel
 #define memory_unmap memory_unmap_mipsel
 #define memory_free memory_free_mipsel
 #define flatview_unref flatview_unref_mipsel
@@ -144,6 +145,7 @@
 #define memory_region_del_subregion memory_region_del_subregion_mipsel
 #define memory_region_add_subregion_overlap memory_region_add_subregion_overlap_mipsel
 #define memory_region_find memory_region_find_mipsel
+#define memory_region_filter_subregions memory_region_filter_subregions_mipsel
 #define memory_listener_register memory_listener_register_mipsel
 #define memory_listener_unregister memory_listener_unregister_mipsel
 #define address_space_remove_listeners address_space_remove_listeners_mipsel

qemu/ppc.h

@@ -123,6 +123,7 @@
 #define memory_map memory_map_ppc
 #define memory_map_io memory_map_io_ppc
 #define memory_map_ptr memory_map_ptr_ppc
+#define memory_cow memory_cow_ppc
 #define memory_unmap memory_unmap_ppc
 #define memory_free memory_free_ppc
 #define flatview_unref flatview_unref_ppc
@@ -144,6 +145,7 @@
 #define memory_region_del_subregion memory_region_del_subregion_ppc
 #define memory_region_add_subregion_overlap memory_region_add_subregion_overlap_ppc
 #define memory_region_find memory_region_find_ppc
+#define memory_region_filter_subregions memory_region_filter_subregions_ppc
 #define memory_listener_register memory_listener_register_ppc
 #define memory_listener_unregister memory_listener_unregister_ppc
 #define address_space_remove_listeners address_space_remove_listeners_ppc

qemu/ppc64.h

@@ -123,6 +123,7 @@
 #define memory_map memory_map_ppc64
 #define memory_map_io memory_map_io_ppc64
 #define memory_map_ptr memory_map_ptr_ppc64
+#define memory_cow memory_cow_ppc64
 #define memory_unmap memory_unmap_ppc64
 #define memory_free memory_free_ppc64
 #define flatview_unref flatview_unref_ppc64
@@ -144,6 +145,7 @@
 #define memory_region_del_subregion memory_region_del_subregion_ppc64
 #define memory_region_add_subregion_overlap memory_region_add_subregion_overlap_ppc64
 #define memory_region_find memory_region_find_ppc64
+#define memory_region_filter_subregions memory_region_filter_subregions_ppc64
 #define memory_listener_register memory_listener_register_ppc64
 #define memory_listener_unregister memory_listener_unregister_ppc64
 #define address_space_remove_listeners address_space_remove_listeners_ppc64

qemu/riscv32.h

@@ -123,6 +123,7 @@
 #define memory_map memory_map_riscv32
 #define memory_map_io memory_map_io_riscv32
 #define memory_map_ptr memory_map_ptr_riscv32
+#define memory_cow memory_cow_riscv32
 #define memory_unmap memory_unmap_riscv32
 #define memory_free memory_free_riscv32
 #define flatview_unref flatview_unref_riscv32
@@ -144,6 +145,7 @@
 #define memory_region_del_subregion memory_region_del_subregion_riscv32
 #define memory_region_add_subregion_overlap memory_region_add_subregion_overlap_riscv32
 #define memory_region_find memory_region_find_riscv32
+#define memory_region_filter_subregions memory_region_filter_subregions_riscv32
 #define memory_listener_register memory_listener_register_riscv32
 #define memory_listener_unregister memory_listener_unregister_riscv32
 #define address_space_remove_listeners address_space_remove_listeners_riscv32

qemu/riscv64.h

@@ -123,6 +123,7 @@
 #define memory_map memory_map_riscv64
 #define memory_map_io memory_map_io_riscv64
 #define memory_map_ptr memory_map_ptr_riscv64
+#define memory_cow memory_cow_riscv64
 #define memory_unmap memory_unmap_riscv64
 #define memory_free memory_free_riscv64
 #define flatview_unref flatview_unref_riscv64
@@ -144,6 +145,7 @@
 #define memory_region_del_subregion memory_region_del_subregion_riscv64
 #define memory_region_add_subregion_overlap memory_region_add_subregion_overlap_riscv64
 #define memory_region_find memory_region_find_riscv64
+#define memory_region_filter_subregions memory_region_filter_subregions_riscv64
 #define memory_listener_register memory_listener_register_riscv64
 #define memory_listener_unregister memory_listener_unregister_riscv64
 #define address_space_remove_listeners address_space_remove_listeners_riscv64

qemu/s390x.h

@@ -123,6 +123,7 @@
 #define memory_map memory_map_s390x
 #define memory_map_io memory_map_io_s390x
 #define memory_map_ptr memory_map_ptr_s390x
+#define memory_cow memory_cow_s390x
 #define memory_unmap memory_unmap_s390x
 #define memory_free memory_free_s390x
 #define flatview_unref flatview_unref_s390x
@@ -144,6 +145,7 @@
 #define memory_region_del_subregion memory_region_del_subregion_s390x
 #define memory_region_add_subregion_overlap memory_region_add_subregion_overlap_s390x
 #define memory_region_find memory_region_find_s390x
+#define memory_region_filter_subregions memory_region_filter_subregions_s390x
 #define memory_listener_register memory_listener_register_s390x
 #define memory_listener_unregister memory_listener_unregister_s390x
 #define address_space_remove_listeners address_space_remove_listeners_s390x