Bug 2511931 (CVE-2026-64591)

Summary: CVE-2026-64591 kernel: iommu/vt-d: Avoid WARNING in sva unbind path
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Intel IOMMU driver. This issue occurs because the driver attempts to disable I/O Page Fault (IOPF) handling for devices that never had it enabled, specifically when Shared Virtual Addressing (SVA) is used on hardware that does not support the PCI Page Request Interface (PRI). This imbalance in the bind and unbind paths can lead to a kernel WARNING message, indicating an unexpected state within the system.
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Description OSIDB Bzimport 2026-08-06 07:31:25 UTC
In the Linux kernel, the following vulnerability has been resolved:

iommu/vt-d: Avoid WARNING in sva unbind path

The Intel IOMMU driver allows SVA on devices even if they do not support
PCI/PRI. Commit 39c20c4e83b9 ("iommu/vt-d: Only handle IOPF for SVA when
PRI is supported") modified the SVA bind path to allow this configuration
by skipping IOPF enablement when PRI is missing. However, it failed to
update the unbind path.

This creates an imbalance: the unbind path attempts to disable IOPF for
a device that never had it enabled, triggering a WARNING in
intel_iommu_disable_iopf():

 WARNING: drivers/iommu/intel/iommu.c:3475 at intel_iommu_disable_iopf+0x4f/0x90d
 Call Trace:
  <TASK>
  blocking_domain_set_dev_pasid+0x50/0x70
  iommu_detach_device_pasid+0x89/0xc0
  iommu_sva_unbind_device+0x73/0x150
  xe_vm_close_and_put+0x4d2/0x1200 [xe]

Fix this by bypassing IOPF operations for SVA domains on non-PRI hardware
in both the bind and unbind paths.