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

[liu ping fan]

On Thu, Aug 9, 2012 at 3:17 AM, Blue Swirl <address@hidden> wrote:
> On Wed, Aug 8, 2012 at 6:25 AM, Liu Ping Fan <address@hidden> wrote:
>> From: Liu Ping Fan <address@hidden>
>>
>> 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 <address@hidden>
>> ---
>>  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);
>
> I'd move this and the mutex to memory.c since there are no other uses.
> The mutex could be static then.
>
But the init entry is in exec.c, not memory.c.

Regards,
pingfan

>>  #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
>>