From: Jan Kiszka <jan.kis...@siemens.com>
This introduces the memory region property "global_locking". It is true
by default. By setting it to false, a device model can request BQL-free
dispatching of region accesses to its r/w handlers. The actual BQL
break-up will be provided in a separate patch.
Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
include/exec/memory.h | 26 ++++++++++++++++++++++++++
memory.c | 11 +++++++++++
2 files changed, 37 insertions(+)
diff --git a/include/exec/memory.h b/include/exec/memory.h
index b61c84f..61791f8 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -180,6 +180,7 @@ struct MemoryRegion {
bool rom_device;
bool warning_printed; /* For reservations */
bool flush_coalesced_mmio;
+ bool global_locking;
MemoryRegion *alias;
hwaddr alias_offset;
int32_t priority;
@@ -812,6 +813,31 @@ void memory_region_set_flush_coalesced(MemoryRegion *mr);
void memory_region_clear_flush_coalesced(MemoryRegion *mr);
/**
+ * memory_region_set_global_locking: Declares the access processing requires
+ * QEMU's global lock.
+ *
+ * When this is invoked, access to this memory regions will be processed while
+ * holding the global lock of QEMU. This is the default behavior of memory
+ * regions.
+ *
+ * @mr: the memory region to be updated.
+ */
+void memory_region_set_global_locking(MemoryRegion *mr);
+
+/**
+ * memory_region_clear_global_locking: Declares that access processing does
+ * not depend on the QEMU global lock.
+ *
+ * By clearing this property, accesses to the memory region will be processed
+ * outside of QEMU's global lock (unless the lock is held on when issuing the
+ * access request). In this case, the device model implementing the access
+ * handlers is responsible for synchronization of concurrency.
+ *
+ * @mr: the memory region to be updated.
+ */
+void memory_region_clear_global_locking(MemoryRegion *mr);
+
+/**
* memory_region_add_eventfd: Request an eventfd to be triggered when a word
* is written to a location.
*
diff --git a/memory.c b/memory.c
index 03c536b..6b77354 100644
--- a/memory.c
+++ b/memory.c
@@ -1004,6 +1004,7 @@ static void memory_region_initfn(Object *obj)
mr->ops = &unassigned_mem_ops;
mr->enabled = true;
mr->romd_mode = true;
+ mr->global_locking = true;
mr->destructor = memory_region_destructor_none;
QTAILQ_INIT(&mr->subregions);
QTAILQ_INIT(&mr->coalesced);
@@ -1627,6 +1628,16 @@ void memory_region_clear_flush_coalesced(MemoryRegion
*mr)
}
}
+void memory_region_set_global_locking(MemoryRegion *mr)
+{
+ mr->global_locking = true;
+}
+
+void memory_region_clear_global_locking(MemoryRegion *mr)
+{
+ mr->global_locking = false;
+}
+
void memory_region_add_eventfd(MemoryRegion *mr,
hwaddr addr,
unsigned size,
--
1.8.3.1
