A MemoryRegion with negative priority was created and
it spans over all the pci address space.
It "intercepts" the accesses to unassigned pci
address space and will follow the pci spec:
1. returns -1 on read
2. does nothing on write
Note: setting the RECEIVED MASTER ABORT bit in the STATUS register
of the device that initiated the transaction will be
implemented in another series
Signed-off-by: Marcel Apfelbaum <marce...@redhat.com>
---
Changes from v4:
- Addressed Michael S. Tsirkin comments
- Changed PCI master_abort_mem ops endian-nes to DEVICE_LITTLE_ENDIAN
- Fixed: overlap master_abort_mem at offset 0, not at
bus->address_space_mem.addr
hw/pci/pci.c | 26 ++++++++++++++++++++++++++
include/hw/pci/pci_bus.h | 1 +
2 files changed, 27 insertions(+)
diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index ad1c1ca..d8a1b11 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -283,6 +283,24 @@ const char *pci_root_bus_path(PCIDevice *dev)
return rootbus->qbus.name;
}
+static uint64_t master_abort_mem_read(void *opaque, hwaddr addr, unsigned size)
+{
+ return -1ULL;
+}
+
+static void master_abort_mem_write(void *opaque, hwaddr addr, uint64_t val,
+ unsigned size)
+{
+}
+
+static const MemoryRegionOps master_abort_mem_ops = {
+ .read = master_abort_mem_read,
+ .write = master_abort_mem_write,
+ .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+#define MASTER_ABORT_MEM_PRIORITY INT_MIN
+
static void pci_bus_init(PCIBus *bus, DeviceState *parent,
const char *name,
MemoryRegion *address_space_mem,
@@ -294,6 +312,14 @@ static void pci_bus_init(PCIBus *bus, DeviceState *parent,
bus->address_space_mem = address_space_mem;
bus->address_space_io = address_space_io;
+
+ memory_region_init_io(&bus->master_abort_mem, OBJECT(bus),
+ &master_abort_mem_ops, bus, "pci-master-abort",
+ memory_region_size(bus->address_space_mem));
+ memory_region_add_subregion_overlap(bus->address_space_mem,
+ 0, &bus->master_abort_mem,
+ MASTER_ABORT_MEM_PRIORITY);
+
/* host bridge */
QLIST_INIT(&bus->child);
diff --git a/include/hw/pci/pci_bus.h b/include/hw/pci/pci_bus.h
index 9df1788..2ad5edb 100644
--- a/include/hw/pci/pci_bus.h
+++ b/include/hw/pci/pci_bus.h
@@ -23,6 +23,7 @@ struct PCIBus {
PCIDevice *parent_dev;
MemoryRegion *address_space_mem;
MemoryRegion *address_space_io;
+ MemoryRegion master_abort_mem;
QLIST_HEAD(, PCIBus) child; /* this will be replaced by qdev later */
QLIST_ENTRY(PCIBus) sibling;/* this will be replaced by qdev later */
--
1.8.3.1
