From 196ea13104f802c508e57180b2a0d2b3418989a3 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Thu, 18 Jun 2015 18:47:20 +0200 Subject: [PATCH] memory: Add global-locking property to memory regions 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 Cc: Frederic Konrad Signed-off-by: Paolo Bonzini Message-Id: <1434646046-27150-4-git-send-email-pbonzini@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 8ae004e..0ebdc55 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; @@ -825,6 +826,31 @@ 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. * diff --git a/memory.c b/memory.c index 3ac0bd2..b0b8860 100644 --- a/memory.c +++ b/memory.c @@ -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, -- 2.7.4