From da72a379b2ec0bad3eb265787f7008bead0b040c Mon Sep 17 00:00:00 2001 From: Daniel Drake Date: Thu, 12 Mar 2020 14:09:55 +0800 Subject: [PATCH] iommu/vt-d: Ignore devices with out-of-spec domain number MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Daniel Drake Fixes: 59ce0515cdaf3 ("iommu/vt-d: Update DRHD/RMRR/ATSR device scope caches when PCI hotplug happens") Signed-off-by: Joerg Roedel --- drivers/iommu/dmar.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c index c7b1461e8d0a..f77dae7ba7d4 100644 --- a/drivers/iommu/dmar.c +++ b/drivers/iommu/dmar.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include @@ -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) -- GitLab