On Fri, 18 Sep 2015 15:08:54 -0600
Alex Williamson <alex.williamson@xxxxxxxxxx> wrote:
Hi Alex,
> SR-IOV creates a virtual bus where bus->self is NULL. This results
> in a segfault as VFs are added and we scan for an MSI domain without
> taking that into account. Detect this and scan up to the parent bus
> until we find a real bridge.
Irk. Sorry about the breakage.
> Fixes: 44aa0c657e3e ("PCI/MSI: Add hooks to populate the msi_domain field")
> Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
> ---
> drivers/pci/probe.c | 17 +++++++++++------
> 1 file changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 0b2be17..b42419e 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -676,15 +676,20 @@ static struct irq_domain *pci_host_bridge_msi_domain(struct pci_bus *bus)
> static void pci_set_bus_msi_domain(struct pci_bus *bus)
> {
> struct irq_domain *d;
> + struct pci_bus *b;
>
> /*
> - * Either bus is the root, and we must obtain it from the
> - * firmware, or we inherit it from the bridge device.
> + * The bus can be a root bus, a subordinate bus, or a virtual bus
> + * created by an SR-IOV device. Walk up to the first bridge device
> + * found or derive the domain from the host bridge.
> */
> - if (pci_is_root_bus(bus))
> - d = pci_host_bridge_msi_domain(bus);
> - else
> - d = dev_get_msi_domain(&bus->self->dev);
> + for (b = bus, d = NULL; !d && !pci_is_root_bus(b); b = b->parent) {
> + if (b->self)
> + d = dev_get_msi_domain(&b->self->dev);
> + }
> +
> + if (!d)
> + d = pci_host_bridge_msi_domain(b);
>
> dev_set_msi_domain(&bus->dev, d);
> }
>
Out of curiosity, is this a common behaviour? I've tested the original
code with an Intel i350 Ethernet interface (IGB+IGBVF), and used it
with virtual functions on my arm64-based Seattle, without any issue. Do
we have divergent implementations of the same functionality in the
kernel? Otherwise:
Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Thanks,
M.
--
Jazz is not dead. It just smells funny.
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