[Qemu-devel] [PATCH 04/15] memory: MemoryRegion topology must be stable when updating

[Liu Ping Fan <qemulist@gmail.com>]

From: Liu Ping Fan <pingfank@linux.vnet.ibm.com>

Using mem_map_lock to protect among updaters. So we can get the intact
snapshot of mem topology -- FlatView & radix-tree.

Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
---
 exec.c   |    3 +++
 memory.c |   22 ++++++++++++++++++++++
 memory.h |    2 ++
 3 files changed, 27 insertions(+), 0 deletions(-)

diff --git a/exec.c b/exec.c
index 8244d54..0e29ef9 100644
--- a/exec.c
+++ b/exec.c
@@ -210,6 +210,8 @@ static unsigned phys_map_nodes_nb, phys_map_nodes_nb_alloc;
    The bottom level has pointers to MemoryRegionSections.  */
 static PhysPageEntry phys_map = { .ptr = PHYS_MAP_NODE_NIL, .is_leaf = 0 };
 
+QemuMutex mem_map_lock;
+
 static void io_mem_init(void);
 static void memory_map_init(void);
 
@@ -637,6 +639,7 @@ void cpu_exec_init_all(void)
 #if !defined(CONFIG_USER_ONLY)
     memory_map_init();
     io_mem_init();
+    qemu_mutex_init(&mem_map_lock);
 #endif
 }
 
diff --git a/memory.c b/memory.c
index aab4a31..5986532 100644
--- a/memory.c
+++ b/memory.c
@@ -761,7 +761,9 @@ void memory_region_transaction_commit(void)
     assert(memory_region_transaction_depth);
     --memory_region_transaction_depth;
     if (!memory_region_transaction_depth && memory_region_update_pending) {
+        qemu_mutex_lock(&mem_map_lock);
         memory_region_update_topology(NULL);
+        qemu_mutex_unlock(&mem_map_lock);
     }
 }
 
@@ -1069,8 +1071,10 @@ void memory_region_set_log(MemoryRegion *mr, bool log, unsigned client)
 {
     uint8_t mask = 1 << client;
 
+    qemu_mutex_lock(&mem_map_lock);
     mr->dirty_log_mask = (mr->dirty_log_mask & ~mask) | (log * mask);
     memory_region_update_topology(mr);
+    qemu_mutex_unlock(&mem_map_lock);
 }
 
 bool memory_region_get_dirty(MemoryRegion *mr, target_phys_addr_t addr,
@@ -1103,8 +1107,10 @@ void memory_region_sync_dirty_bitmap(MemoryRegion *mr)
 void memory_region_set_readonly(MemoryRegion *mr, bool readonly)
 {
     if (mr->readonly != readonly) {
+        qemu_mutex_lock(&mem_map_lock);
         mr->readonly = readonly;
         memory_region_update_topology(mr);
+        qemu_mutex_unlock(&mem_map_lock);
     }
 }
 
@@ -1112,7 +1118,9 @@ void memory_region_rom_device_set_readable(MemoryRegion *mr, bool readable)
 {
     if (mr->readable != readable) {
         mr->readable = readable;
+        qemu_mutex_lock(&mem_map_lock);
         memory_region_update_topology(mr);
+        qemu_mutex_unlock(&mem_map_lock);
     }
 }
 
@@ -1206,6 +1214,7 @@ void memory_region_add_eventfd(MemoryRegion *mr,
     };
     unsigned i;
 
+    qemu_mutex_lock(&mem_map_lock);
     for (i = 0; i < mr->ioeventfd_nb; ++i) {
         if (memory_region_ioeventfd_before(mrfd, mr->ioeventfds[i])) {
             break;
@@ -1218,6 +1227,7 @@ void memory_region_add_eventfd(MemoryRegion *mr,
             sizeof(*mr->ioeventfds) * (mr->ioeventfd_nb-1 - i));
     mr->ioeventfds[i] = mrfd;
     memory_region_update_topology(mr);
+    qemu_mutex_unlock(&mem_map_lock);
 }
 
 void memory_region_del_eventfd(MemoryRegion *mr,
@@ -1236,6 +1246,7 @@ void memory_region_del_eventfd(MemoryRegion *mr,
     };
     unsigned i;
 
+    qemu_mutex_lock(&mem_map_lock);
     for (i = 0; i < mr->ioeventfd_nb; ++i) {
         if (memory_region_ioeventfd_equal(mrfd, mr->ioeventfds[i])) {
             break;
@@ -1248,6 +1259,7 @@ void memory_region_del_eventfd(MemoryRegion *mr,
     mr->ioeventfds = g_realloc(mr->ioeventfds,
                                   sizeof(*mr->ioeventfds)*mr->ioeventfd_nb + 1);
     memory_region_update_topology(mr);
+    qemu_mutex_unlock(&mem_map_lock);
 }
 
 static void memory_region_add_subregion_common(MemoryRegion *mr,
@@ -1259,6 +1271,8 @@ static void memory_region_add_subregion_common(MemoryRegion *mr,
     assert(!subregion->parent);
     subregion->parent = mr;
     subregion->addr = offset;
+
+    qemu_mutex_lock(&mem_map_lock);
     QTAILQ_FOREACH(other, &mr->subregions, subregions_link) {
         if (subregion->may_overlap || other->may_overlap) {
             continue;
@@ -1289,6 +1303,7 @@ static void memory_region_add_subregion_common(MemoryRegion *mr,
     QTAILQ_INSERT_TAIL(&mr->subregions, subregion, subregions_link);
 done:
     memory_region_update_topology(mr);
+    qemu_mutex_unlock(&mem_map_lock);
 }
 
 
@@ -1316,8 +1331,11 @@ void memory_region_del_subregion(MemoryRegion *mr,
 {
     assert(subregion->parent == mr);
     subregion->parent = NULL;
+
+    qemu_mutex_lock(&mem_map_lock);
     QTAILQ_REMOVE(&mr->subregions, subregion, subregions_link);
     memory_region_update_topology(mr);
+    qemu_mutex_unlock(&mem_map_lock);
 }
 
 void memory_region_set_enabled(MemoryRegion *mr, bool enabled)
@@ -1325,8 +1343,10 @@ void memory_region_set_enabled(MemoryRegion *mr, bool enabled)
     if (enabled == mr->enabled) {
         return;
     }
+    qemu_mutex_lock(&mem_map_lock);
     mr->enabled = enabled;
     memory_region_update_topology(NULL);
+    qemu_mutex_unlock(&mem_map_lock);
 }
 
 void memory_region_set_address(MemoryRegion *mr, target_phys_addr_t addr)
@@ -1361,7 +1381,9 @@ void memory_region_set_alias_offset(MemoryRegion *mr, target_phys_addr_t offset)
         return;
     }
 
+    qemu_mutex_lock(&mem_map_lock);
     memory_region_update_topology(mr);
+    qemu_mutex_unlock(&mem_map_lock);
 }
 
 ram_addr_t memory_region_get_ram_addr(MemoryRegion *mr)
diff --git a/memory.h b/memory.h
index 740c48e..fe6aefa 100644
--- a/memory.h
+++ b/memory.h
@@ -25,6 +25,7 @@
 #include "iorange.h"
 #include "ioport.h"
 #include "int128.h"
+#include "qemu-thread.h"
 
 typedef struct MemoryRegionOps MemoryRegionOps;
 typedef struct MemoryRegion MemoryRegion;
@@ -207,6 +208,7 @@ struct MemoryListener {
     QTAILQ_ENTRY(MemoryListener) link;
 };
 
+extern QemuMutex mem_map_lock;
 /**
  * memory_region_init: Initialize a memory region
  *
-- 
1.7.4.4