On Fri, Aug 09, 2013 at 07:48:16PM +1000, Alexey Kardashevskiy wrote:
> On 08/09/2013 07:40 PM, Paolo Bonzini wrote:
> > Il 09/08/2013 10:49, Alexey Kardashevskiy ha scritto:
> >> A PCI device's DMA address space (possibly an IOMMU) is returned by a
> >> method on the PCIBus. At the moment that only has one caller, so the
> >> method is simply open coded. We'll need another caller for VFIO, so
> >> this patch introduces a helper/wrapper function.
> >>
> >> Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
> >> [aik: added inheritance from parent if iommu is not set for the current
> >> bus]
> >> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
> >>
> >> ---
> >> Changes:
> >> v2:
> >> * added inheritance, needed for a pci-bridge on spapr-ppc64
> >> * pci_iommu_as renamed to pci_device_iommu_address_space
> >> ---
> >> hw/pci/pci.c | 22 ++++++++++++++++------
> >> include/hw/pci/pci.h | 1 +
> >> 2 files changed, 17 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> >> index 4c004f5..0072b54 100644
> >> --- a/hw/pci/pci.c
> >> +++ b/hw/pci/pci.c
> >> @@ -812,12 +812,7 @@ static PCIDevice *do_pci_register_device(PCIDevice
> >> *pci_dev, PCIBus *bus,
> >> }
> >>
> >> pci_dev->bus = bus;
> >> - if (bus->iommu_fn) {
> >> - dma_as = bus->iommu_fn(bus, bus->iommu_opaque, devfn);
> >> - } else {
> >> - /* FIXME: inherit memory region from bus creator */
> >> - dma_as = &address_space_memory;
> >> - }
> >> + dma_as = pci_device_iommu_address_space(pci_dev);
> >>
> >> memory_region_init_alias(&pci_dev->bus_master_enable_region,
> >> OBJECT(pci_dev), "bus master",
> >> @@ -2239,6 +2234,21 @@ static void pci_device_class_init(ObjectClass
> >> *klass, void *data)
> >> k->props = pci_props;
> >> }
> >>
> >> +AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)
> >> +{
> >> + PCIBus *bus = PCI_BUS(dev->bus);
> >> +
> >> + if (bus->iommu_fn) {
> >> + return bus->iommu_fn(bus, bus->iommu_opaque, dev->devfn);
> >> + }
> >> +
> >> + if (bus->parent_dev) {
> >> + return pci_device_iommu_address_space(bus->parent_dev);
> >> + }
> >
> > No, this would fail if bus->parent_dev is not NULL but not a PCI device
> > either.
>
> parent_dev is of the PCIDevice* type, how can it be not a PCI device? :-/
It will be a PCI device, though the confusion is understandable.
There is a parent_dev in both PCIBus, which is always a PCI device if
non-NULL, as well as a parent_dev in BusState, which can be any sort
of device. If both are non-NULL they will be equal apart from type.
So bus->parent_dev is safe here, bus->qbus.parent_dev would not be.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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