Affected: Linux

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.