On Thu, Apr 20, 2017 at 10:04:57PM -0700, Yinghai Lu wrote: > If any bridge up to root only have 32bit pref mmio, We don't need to > treat device non-pref mmio64 as as pref mmio64.
I don't understand the reasoning here. Apparently it is only safe to put a non-prefetchable PCIe BAR in a prefetchable window if all upstream bridges have a 64-bit prefetchable window? Why is that? Why is it important that the prefetchable window be 64-bit? I don't see this mentioned in the implementation note. Does this mean "PCI: Check pref compatible bit for mem64 resource of PCIe device" can make unsafe assignments until we apply this patch? If so, I don't want that sort of bisection hole. What bad thing happens without this patch? > We need to move pci_bridge_check_ranges calling early. > For parent bridges pref mmio BAR may not allocated by BIOS, res flags > is still 0, we need to have it correct set before we check them for > child device resources. > > -v2: check all bus resources instead of just res[15]. > > Signed-off-by: Yinghai Lu <[email protected]> > Tested-by: Khalid Aziz <[email protected]> > --- > drivers/pci/setup-bus.c | 31 +++++++++++++++++++++++++++++-- > 1 file changed, 29 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c > index 3de66e6..b3fd314 100644 > --- a/drivers/pci/setup-bus.c > +++ b/drivers/pci/setup-bus.c > @@ -735,6 +735,29 @@ int pci_claim_bridge_resource(struct pci_dev *bridge, > int i) > return -EINVAL; > } > > +static bool pci_up_path_over_pref_mem64(struct pci_bus *bus) > +{ > + if (pci_is_root_bus(bus)) > + return true; > + > + if (bus->self) { > + int i; > + bool found = false; > + struct resource *res; > + > + pci_bus_for_each_resource(bus, res, i) > + if (res->flags & IORESOURCE_MEM_64) { > + found = true; > + break; > + } > + > + if (!found) > + return false; > + } > + > + return pci_up_path_over_pref_mem64(bus->parent); > +} > + > int pci_resource_pref_compatible(const struct pci_dev *dev, > struct resource *res) > { > @@ -743,7 +766,8 @@ int pci_resource_pref_compatible(const struct pci_dev > *dev, > > if ((res->flags & IORESOURCE_MEM) && > (res->flags & IORESOURCE_MEM_64) && > - dev->on_all_pcie_path) > + dev->on_all_pcie_path && > + pci_up_path_over_pref_mem64(dev->bus)) > return res->flags | IORESOURCE_PREFETCH; > > return res->flags; > @@ -1236,6 +1260,10 @@ void __pci_bus_size_bridges(struct pci_bus *bus, > struct list_head *realloc_head) > struct resource *b_res; > int ret; > > + if (!pci_is_root_bus(bus) && > + (bus->self->class >> 8) == PCI_CLASS_BRIDGE_PCI) > + pci_bridge_check_ranges(bus); > + > list_for_each_entry(dev, &bus->devices, bus_list) { > struct pci_bus *b = dev->subordinate; > if (!b) > @@ -1263,7 +1291,6 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct > list_head *realloc_head) > break; > > case PCI_CLASS_BRIDGE_PCI: > - pci_bridge_check_ranges(bus); > if (bus->self->is_hotplug_bridge) { > additional_io_size = pci_hotplug_io_size; > additional_mem_size = pci_hotplug_mem_size; > -- > 2.9.3 >
