Messages in this thread | | | Date | Sun, 20 Sep 2015 12:58:48 +0100 | From | Marc Zyngier <> | Subject | Re: [PATCH] PCI/MSI: Fix MSI IRQ domains for SR-IOV |
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On Fri, 18 Sep 2015 15:08:54 -0600 Alex Williamson <alex.williamson@redhat.com> 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@redhat.com> > --- > 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@arm.com>
Thanks,
M. -- Jazz is not dead. It just smells funny.
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