From 38ea72bdb65df2f40ec77b2c9d1413e7f5e34465 Mon Sep 17 00:00:00 2001
From: Alex Williamson <alex.williamson@redhat.com>
Date: Fri, 18 Sep 2015 15:08:54 -0600
Subject: [PATCH] PCI/MSI: Fix MSI IRQ domains for VFs on virtual buses
SR-IOV creates a virtual bus where bus->self is NULL. When we add VFs and
scan for an MSI domain, pci_set_bus_msi_domain() dereferences bus->self,
which causes a kernel NULL pointer dereference oops.
Scan up to the parent bus until we find a real bridge where we can get the
MSI domain.
[bhelgaas: changelog]
Fixes: 44aa0c657e3e ("PCI/MSI: Add hooks to populate the msi_domain field")
Tested-by: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.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 c8cc0e62a7b9d2..8361d27e5ecad8 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);
}
--
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