From def054b01a867822254e1dda13d587f5c7a99e2a Mon Sep 17 00:00:00 2001 From: Lu Baolu Date: Tue, 27 Feb 2024 10:14:41 +0800 Subject: iommu/vt-d: Use device rbtree in iopf reporting path The existing I/O page fault handler currently locates the PCI device by calling pci_get_domain_bus_and_slot(). This function searches the list of all PCI devices until the desired device is found. To improve lookup efficiency, replace it with device_rbtree_find() to search the device within the probed device rbtree. The I/O page fault is initiated by the device, which does not have any synchronization mechanism with the software to ensure that the device stays in the probed device tree. Theoretically, a device could be released by the IOMMU subsystem after device_rbtree_find() and before iopf_get_dev_fault_param(), which would cause a use-after-free problem. Add a mutex to synchronize the I/O page fault reporting path and the IOMMU release device path. This lock doesn't introduce any performance overhead, as the conflict between I/O page fault reporting and device releasing is very rare. Signed-off-by: Lu Baolu Reviewed-by: Jason Gunthorpe Link: https://lore.kernel.org/r/20240220065939.121116-3-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel --- drivers/iommu/intel/iommu.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/iommu/intel/iommu.c') diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 025d7385cf58..60aa2dce32ef 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -4362,8 +4362,11 @@ free: static void intel_iommu_release_device(struct device *dev) { struct device_domain_info *info = dev_iommu_priv_get(dev); + struct intel_iommu *iommu = info->iommu; + mutex_lock(&iommu->iopf_lock); device_rbtree_remove(info); + mutex_unlock(&iommu->iopf_lock); dmar_remove_one_dev_info(dev); intel_pasid_free_table(dev); intel_iommu_debugfs_remove_dev(info); -- cgit v1.2.3