irq_remap: disable IRQ remapping if any IOAPIC lacks an IOMMU

The ACPI tables in the Macbook Air 5,1 define a single IOAPIC with id 2,
but the only remapping unit described in the DMAR table matches id 0.
Interrupt remapping fails as a result, and the kernel panics with the
message "timer doesn't work through Interrupt-remapped IO-APIC."

To fix this, check each IOAPIC for a corresponding IOMMU. If an IOMMU is
not found, do not allow IRQ remapping to be enabled.

v2: Move check to parse_ioapics_under_ir(), raise log level to KERN_ERR,
    and add FW_BUG to the log message
v3: Skip check if IOMMU doesn't support interrupt remapping and remove
    existing check that the IOMMU count equals the IOAPIC count

Acked-by: Suresh Siddha <[email protected]>
Signed-off-by: Seth Forshee <[email protected]>
Acked-by: Yinghai Lu <[email protected]>
Signed-off-by: Joerg Roedel <[email protected]>

0 files changed, 0 insertions, 0 deletions