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memory: Add global-locking property to memory regions

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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.kiszka@siemens.com>
Cc: Frederic Konrad <fred.konrad@greensocs.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1434646046-27150-4-git-send-email-pbonzini@redhat.com>
This commit is contained in:
Jan Kiszka 2015-06-18 18:47:20 +02:00 committed by Paolo Bonzini
parent afbe70535f
commit 196ea13104
2 changed files with 37 additions and 0 deletions
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26
include/exec/memory.h
View File

@ -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;
@ -824,6 +825,31 @@ 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, accesses to the memory region 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.

11
memory.c
View File

@ -1012,6 +1012,7 @@ static void memory_region_initfn(Object *obj)
mr->ram_addr = RAM_ADDR_INVALID;
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);
@ -1646,6 +1647,16 @@ 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,