Commit a53ae8e9 authored by Marcel Apfelbaum's avatar Marcel Apfelbaum Committed by Michael S. Tsirkin
Browse files

hw/pci: partially handle pci master abort 



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: default avatarMarcel Apfelbaum <marcel.a@redhat.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 8002ccd6

hw/pci/pci.c

+26 −0
Original line number Diff line number Diff line
@@ -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);

include/hw/pci/pci_bus.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */