On Tue, Jun 19, 2018 at 5:07 AM, Peter Maydell <[email protected]> wrote: > Currently we use memory_region_init_rom_nomigrate() to create > the "io" memory region to pass to pci_register_root_bus(). > This is a dummy region, because this PCI controller doesn't > support accesses to PCI IO space. > > There is no reason for the dummy region to be a RAM region; > it is only used as a place where PCI BARs can be mapped, > and if you could get a PCI card to do a bus master access > to the IO space it should not get acts-like-RAM behaviour. > Use a simple container memory region instead. (We do have > one PCI card model which can do bus master accesses to IO > space -- the LSI53C895A SCSI adaptor.) > > This avoids the oddity of having a memory region which is > RAM but where the RAM is not migrated. > > Note that the size of the region we use here has no > effect on behaviour. > > Signed-off-by: Peter Maydell <[email protected]>
Reviewed-by: Alistair Francis <[email protected]> Alistair > --- > hw/pci-host/xilinx-pcie.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/hw/pci-host/xilinx-pcie.c b/hw/pci-host/xilinx-pcie.c > index 044e312dc18..b0a31b917d8 100644 > --- a/hw/pci-host/xilinx-pcie.c > +++ b/hw/pci-host/xilinx-pcie.c > @@ -120,9 +120,8 @@ static void xilinx_pcie_host_realize(DeviceState *dev, > Error **errp) > memory_region_init(&s->mmio, OBJECT(s), "mmio", UINT64_MAX); > memory_region_set_enabled(&s->mmio, false); > > - /* dummy I/O region */ > - memory_region_init_ram_nomigrate(&s->io, OBJECT(s), "io", 16, NULL); > - memory_region_set_enabled(&s->io, false); > + /* dummy PCI I/O region (not visible to the CPU) */ > + memory_region_init(&s->io, OBJECT(s), "io", 16); > > /* interrupt out */ > qdev_init_gpio_out_named(dev, &s->irq, "interrupt_out", 1); > -- > 2.17.1 > >
