PCI spec requires that a transaction that has not been claimed by any PCI bus devices will be terminated by the initiator with "master abort". For read transactions -1(FFFFFFFF) is returned and writes are silently dropped.
Implementation: - Allowed the MemoryRegion priority to be negative so a subregion will be visible on all the addresses not covered by other container subregions. - Added a memory region with negative priority that extends over all the pci address space. This region catches all the accesses to the unassigned pci addresses. - The MemoryRegion's ops emulates the master abort scenario. I am working on implementing the following on top of this series - Implement upstream master abort - Handling of RECEIVED MASTER ABORT BIT in Status register Changes from v4: - Addressed Peter Maydell comments - Changed memory patches commit comment - Addressed Michael S. Tsirkin comments - Changed PCI master_abort_mem ops endian-nes to DEVICE_LITTLE_ENDIAN Changes from v3: - Addressed Peter Maydell comments - Removed unnecessary changes to priority of MemoryListener - Ensured that priority is now signed in all related places - Added to memory docs explanation on signed priorities - Addresses Michael S. Tsirkin comments - Changed the name of the new Memory region to master_abort_mem - Made master abort priority INT_MIN instead of -1 - Removed handling of RECEIVED MASTER ABORT BIT; it will be taken care in a different series Changes from v2: - minor: changed nr of patches in the title - minor: modified series list Changes from v1: - "pci-unassigned-mem" MemoryRegion resides now in PCIBus and not on various Host Bridges - "pci-unassgined-mem" does not have a ".valid.accept" field and implements read write methods Marcel Apfelbaum (3): memory: Change MemoryRegion priorities from unsigned to signed docs/memory: Explictly state that MemoryRegion priority is signed hw/pci: partially handle pci master abort docs/memory.txt | 4 ++++ hw/core/sysbus.c | 4 ++-- hw/pci/pci.c | 27 +++++++++++++++++++++++++++ include/exec/memory.h | 4 ++-- include/hw/pci/pci_bus.h | 1 + include/hw/sysbus.h | 2 +- memory.c | 4 ++-- 7 files changed, 39 insertions(+), 7 deletions(-) -- 1.8.3.1