CVE-2025-38216

In the Linux kernel, the following vulnerability has been resolved:

iommu/vt-d: Restore context entry setup order for aliased devices

Commit 2031c469f816 ("iommu/vt-d: Add support for static identity domain") changed the context entry setup during domain attachment from a set-and-check policy to a clear-and-reset approach. This inadvertently introduced a regression affecting PCI aliased devices behind PCIe-to-PCI bridges.

Specifically, keyboard and touchpad stopped working on several Apple Macbooks with below messages:

kernel: platform pxa2xx-spi.3: Adding to iommu group 20 kernel: input: Apple SPI Keyboard as /devices/pci0000:00/0000:00:1e.3/pxa2xx-spi.3/spi_master/spi2/spi-APP000D:00/input/input0 kernel: DMAR: DRHD: handling fault status reg 3 kernel: DMAR: [DMA Read NO_PASID] Request device [00:1e.3] fault addr 0xffffa000 [fault reason 0x06] PTE Read access is not set kernel: DMAR: DRHD: handling fault status reg 3 kernel: DMAR: [DMA Read NO_PASID] Request device [00:1e.3] fault addr 0xffffa000 [fault reason 0x06] PTE Read access is not set kernel: applespi spi-APP000D:00: Error writing to device: 01 0e 00 00 kernel: DMAR: DRHD: handling fault status reg 3 kernel: DMAR: [DMA Read NO_PASID] Request device [00:1e.3] fault addr 0xffffa000 [fault reason 0x06] PTE Read access is not set kernel: DMAR: DRHD: handling fault status reg 3 kernel: applespi spi-APP000D:00: Error writing to device: 01 0e 00 00

Fix this by restoring the previous context setup order.

This vulnerability is rated as Moderate impact for Red Hat Enterprise Linux because the flaw results in a local denial of service limited to specific hardware devices, without permitting privilege escalation or arbitrary code execution. The condition requires an Intel VT-d enabled host utilizing specific PCI aliasing topologies behind PCIe-to-PCI bridges. Most enterprise server deployments and standard configurations do not rely on this specialized hardware layout, significantly limiting the operational risk.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.