Re: [Qemu-devel] [PATCH v6 19/33] dimm: keep the state of the whole backend memory

[Vladimir Sementsov-Ogievskiy]

On 30.10.2015 08:56, Xiao Guangrong wrote:

QEMU keeps the state of memory of dimm device during live migration,
however, it is not enough for nvdimm device as its memory does not
contain its label data, so that we should protect the whole backend
memory instead

Signed-off-by: Xiao Guangrong 
---
  hw/mem/dimm.c | 14 --
  1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/hw/mem/dimm.c b/hw/mem/dimm.c
index 498d380..7d1 100644
--- a/hw/mem/dimm.c
+++ b/hw/mem/dimm.c
@@ -134,9 +134,16 @@ void dimm_memory_plug(DeviceState *dev, MemoryHotplugState 
*hpms,
  }
  
  memory_region_add_subregion(>mr, addr - hpms->base, mr);

-vmstate_register_ram(mr, dev);
  numa_set_mem_node_id(addr, memory_region_size(mr), dimm->node);
  
+/*

+ * save the state only for @mr is not enough as it does not contain
+ * the label data of NVDIMM device, so that we keep the state of
+ * whole hostmem instead.
+ */
+vmstate_register_ram(host_memory_backend_get_memory(dimm->hostmem, errp),
+ dev);
+
  out:
  error_propagate(errp, local_err);
  }
@@ -145,10 +152,13 @@ void dimm_memory_unplug(DeviceState *dev, 
MemoryHotplugState *hpms,
 MemoryRegion *mr)
  {
  DIMMDevice *dimm = DIMM(dev);
+MemoryRegion *backend_mr;
+
+backend_mr = host_memory_backend_get_memory(dimm->hostmem, _abort);
  
  numa_unset_mem_node_id(dimm->addr, memory_region_size(mr), dimm->node);

  memory_region_del_subregion(>mr, mr);
-vmstate_unregister_ram(mr, dev);
+vmstate_unregister_ram(backend_mr, dev);
  }
  
  int qmp_dimm_device_list(Object *obj, void *opaque)


should get_memory_region be used here like in previous patch?

--
Best regards,
Vladimir
* now, @virtuozzo.com instead of @parallels.com. Sorry for this inconvenience.

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Re: [Qemu-devel] [PATCH v6 19/33] dimm: keep the state of the whole backend memory

[Xiao Guangrong]

On 10/31/2015 07:05 PM, Vladimir Sementsov-Ogievskiy wrote:

On 30.10.2015 08:56, Xiao Guangrong wrote:

QEMU keeps the state of memory of dimm device during live migration,
however, it is not enough for nvdimm device as its memory does not
contain its label data, so that we should protect the whole backend
memory instead

Signed-off-by: Xiao Guangrong 
---
  hw/mem/dimm.c | 14 --
  1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/hw/mem/dimm.c b/hw/mem/dimm.c
index 498d380..7d1 100644
--- a/hw/mem/dimm.c
+++ b/hw/mem/dimm.c
@@ -134,9 +134,16 @@ void dimm_memory_plug(DeviceState *dev, MemoryHotplugState 
*hpms,
  }
  memory_region_add_subregion(>mr, addr - hpms->base, mr);
-vmstate_register_ram(mr, dev);
  numa_set_mem_node_id(addr, memory_region_size(mr), dimm->node);
+/*
+ * save the state only for @mr is not enough as it does not contain
+ * the label data of NVDIMM device, so that we keep the state of
+ * whole hostmem instead.
+ */
+vmstate_register_ram(host_memory_backend_get_memory(dimm->hostmem, errp),
+ dev);
+
  out:
  error_propagate(errp, local_err);
  }
@@ -145,10 +152,13 @@ void dimm_memory_unplug(DeviceState *dev, 
MemoryHotplugState *hpms,
 MemoryRegion *mr)
  {
  DIMMDevice *dimm = DIMM(dev);
+MemoryRegion *backend_mr;
+
+backend_mr = host_memory_backend_get_memory(dimm->hostmem, _abort);
  numa_unset_mem_node_id(dimm->addr, memory_region_size(mr), dimm->node);
  memory_region_del_subregion(>mr, mr);
-vmstate_unregister_ram(mr, dev);
+vmstate_unregister_ram(backend_mr, dev);
  }
  int qmp_dimm_device_list(Object *obj, void *opaque)


should get_memory_region be used here like in previous patch?



No, it's different.

@get_memory_region() is used to get the memory region mapping to guest's 
address space.
Hovever for NVDIMM we have two kind of regions, one is @get_memory_region, 
another is only
used in QEMU as NVDIMM's label data. host_memory_backend_get_memory() exactly 
gets the whole
memory.

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