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[Qemu-devel] [PATCH 1/3] memory: allow destroying a non-empty MemoryRegi
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 1/3] memory: allow destroying a non-empty MemoryRegion |
Date: |
Tue, 29 Sep 2015 14:37:41 +0200 |
This is legal; the MemoryRegion will simply unreference all the
existing subregions and possibly bring them down with it as well.
However, it requires a bit of care to avoid an infinite loop.
Finalizing a memory region cannot trigger an address space update,
but memory_region_del_subregion errs on the side of caution and
might trigger a spurious update: avoid that by resetting mr->enabled
first.
Signed-off-by: Paolo Bonzini <address@hidden>
---
memory.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/memory.c b/memory.c
index ef87363..73d28ba 100644
--- a/memory.c
+++ b/memory.c
@@ -1304,7 +1304,22 @@ static void memory_region_finalize(Object *obj)
{
MemoryRegion *mr = MEMORY_REGION(obj);
- assert(QTAILQ_EMPTY(&mr->subregions));
+ assert(!mr->container);
+
+ /* We know the region is not visible in any address space (it
+ * does not have a container and cannot be a root either because
+ * it has no references, so we can blindly clear mr->enabled.
+ * memory_region_set_enabled instead could trigger a transaction
+ * and cause an infinite loop.
+ */
+ mr->enabled = false;
+ memory_region_transaction_begin();
+ while (!QTAILQ_EMPTY(&mr->subregions)) {
+ MemoryRegion *subregion = QTAILQ_FIRST(&mr->subregions);
+ memory_region_del_subregion(mr, subregion);
+ }
+ memory_region_transaction_commit();
+
mr->destructor(mr);
memory_region_clear_coalescing(mr);
g_free((char *)mr->name);
--
2.5.0
Re: [Qemu-devel] [PATCH 2/3] hw: do not pass NULL to memory_region_init from instance_init, Markus Armbruster, 2015/10/08