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[PATCH v3 2/3] memory: Make memory_region_is_mapped() succeed when mappe
From: |
David Hildenbrand |
Subject: |
[PATCH v3 2/3] memory: Make memory_region_is_mapped() succeed when mapped via an alias |
Date: |
Tue, 2 Nov 2021 17:43:16 +0100 |
memory_region_is_mapped() currently does not return "true" when a memory
region is mapped via an alias.
Assuming we have:
alias (A0) -> alias (A1) -> region (R0)
Mapping A0 would currently only make memory_region_is_mapped() succeed
on A0, but not on A1 and R0.
Let's fix that by adding a "mapped_via_alias" counter to memory regions and
updating it accordingly when an alias gets (un)mapped.
I am not aware of actual issues, this is rather a cleanup to make it
consistent.
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
include/exec/memory.h | 1 +
softmmu/memory.c | 13 ++++++++++++-
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 20f1b27377..fea1a493b9 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -738,6 +738,7 @@ struct MemoryRegion {
const MemoryRegionOps *ops;
void *opaque;
MemoryRegion *container;
+ int mapped_via_alias; /* Mapped via an alias, container might be NULL */
Int128 size;
hwaddr addr;
void (*destructor)(MemoryRegion *mr);
diff --git a/softmmu/memory.c b/softmmu/memory.c
index 7340e19ff5..b52b6a2f66 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -2535,8 +2535,13 @@ static void
memory_region_add_subregion_common(MemoryRegion *mr,
hwaddr offset,
MemoryRegion *subregion)
{
+ MemoryRegion *alias;
+
assert(!subregion->container);
subregion->container = mr;
+ for (alias = subregion->alias; alias; alias = alias->alias) {
+ alias->mapped_via_alias++;
+ }
subregion->addr = offset;
memory_region_update_container_subregions(subregion);
}
@@ -2561,9 +2566,15 @@ void memory_region_add_subregion_overlap(MemoryRegion
*mr,
void memory_region_del_subregion(MemoryRegion *mr,
MemoryRegion *subregion)
{
+ MemoryRegion *alias;
+
memory_region_transaction_begin();
assert(subregion->container == mr);
subregion->container = NULL;
+ for (alias = subregion->alias; alias; alias = alias->alias) {
+ alias->mapped_via_alias--;
+ assert(alias->mapped_via_alias >= 0);
+ }
QTAILQ_REMOVE(&mr->subregions, subregion, subregions_link);
memory_region_unref(subregion);
memory_region_update_pending |= mr->enabled && subregion->enabled;
@@ -2660,7 +2671,7 @@ static FlatRange *flatview_lookup(FlatView *view,
AddrRange addr)
bool memory_region_is_mapped(MemoryRegion *mr)
{
- return mr->container ? true : false;
+ return !!mr->container || mr->mapped_via_alias;
}
/* Same as memory_region_find, but it does not add a reference to the
--
2.31.1