From: Eric Auger eric.auger@redhat.com
mainline inclusion from mainline-5.3 commit b9a7f9816483b193 category: bugfix bugzilla: 17401 CVE: NA
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Several call sites are about to check whether a device belongs to the PCI sub-hierarchy of a candidate PCI-PCI bridge. Introduce an helper to perform that check.
Signed-off-by: Eric Auger eric.auger@redhat.com Reviewed-by: Lu Baolu baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Xiongfeng Wang wangxiongfeng2@huawei.com Reviewed-by: Hanjun Guo guohanjun@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/iommu/intel-iommu.c | 37 +++++++++++++++++++++++++++++-------- 1 file changed, 29 insertions(+), 8 deletions(-)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index f6d7955..2f52ea8 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -826,12 +826,39 @@ static int iommu_dummy(struct device *dev) return dev->archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO; }
+/** + * is_downstream_to_pci_bridge - test if a device belongs to the PCI + * sub-hierarchy of a candidate PCI-PCI bridge + * @dev: candidate PCI device belonging to @bridge PCI sub-hierarchy + * @bridge: the candidate PCI-PCI bridge + * + * Return: true if @dev belongs to @bridge PCI sub-hierarchy, else false. + */ +static bool +is_downstream_to_pci_bridge(struct device *dev, struct device *bridge) +{ + struct pci_dev *pdev, *pbridge; + + if (!dev_is_pci(dev) || !dev_is_pci(bridge)) + return false; + + pdev = to_pci_dev(dev); + pbridge = to_pci_dev(bridge); + + if (pbridge->subordinate && + pbridge->subordinate->number <= pdev->bus->number && + pbridge->subordinate->busn_res.end >= pdev->bus->number) + return true; + + return false; +} + static struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devfn) { struct dmar_drhd_unit *drhd = NULL; struct intel_iommu *iommu; struct device *tmp; - struct pci_dev *ptmp, *pdev = NULL; + struct pci_dev *pdev = NULL; u16 segment = 0; int i;
@@ -877,13 +904,7 @@ static struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devf goto out; }
- if (!pdev || !dev_is_pci(tmp)) - continue; - - ptmp = to_pci_dev(tmp); - if (ptmp->subordinate && - ptmp->subordinate->number <= pdev->bus->number && - ptmp->subordinate->busn_res.end >= pdev->bus->number) + if (is_downstream_to_pci_bridge(dev, tmp)) goto got_pdev; }