From: Daniel Drake drake@endlessm.com
[ Upstream commit da72a379b2ec0bad3eb265787f7008bead0b040c ]
VMD subdevices are created with a PCI domain ID of 0x10000 or higher.
These subdevices are also handled like all other PCI devices by dmar_pci_bus_notifier().
However, when dmar_alloc_pci_notify_info() take records of such devices, it will truncate the domain ID to a u16 value (in info->seg). The device at (e.g.) 10000:00:02.0 is then treated by the DMAR code as if it is 0000:00:02.0.
In the unlucky event that a real device also exists at 0000:00:02.0 and also has a device-specific entry in the DMAR table, dmar_insert_dev_scope() will crash on: BUG_ON(i >= devices_cnt);
That's basically a sanity check that only one PCI device matches a single DMAR entry; in this case we seem to have two matching devices.
Fix this by ignoring devices that have a domain number higher than what can be looked up in the DMAR table.
This problem was carefully diagnosed by Jian-Hong Pan.
Signed-off-by: Lu Baolu baolu.lu@linux.intel.com Signed-off-by: Daniel Drake drake@endlessm.com Fixes: 59ce0515cdaf3 ("iommu/vt-d: Update DRHD/RMRR/ATSR device scope caches when PCI hotplug happens") Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/dmar.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c index aa15155b9401f..34e705d3b6bb6 100644 --- a/drivers/iommu/dmar.c +++ b/drivers/iommu/dmar.c @@ -28,6 +28,7 @@ #include <linux/slab.h> #include <linux/iommu.h> #include <linux/numa.h> +#include <linux/limits.h> #include <asm/irq_remapping.h> #include <asm/iommu_table.h>
@@ -128,6 +129,13 @@ dmar_alloc_pci_notify_info(struct pci_dev *dev, unsigned long event)
BUG_ON(dev->is_virtfn);
+ /* + * Ignore devices that have a domain number higher than what can + * be looked up in DMAR, e.g. VMD subdevices with domain 0x10000 + */ + if (pci_domain_nr(dev->bus) > U16_MAX) + return NULL; + /* Only generate path[] for device addition event */ if (event == BUS_NOTIFY_ADD_DEVICE) for (tmp = dev; tmp; tmp = tmp->bus->self)