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
Acked-by: Suresh Siddha <[email protected]>
Signed-off-by: Seth Forshee <[email protected]>
---
drivers/iommu/intel_irq_remapping.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/iommu/intel_irq_remapping.c
b/drivers/iommu/intel_irq_remapping.c
index e0b18f3..84e5dc3 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -736,6 +736,7 @@ int __init parse_ioapics_under_ir(void)
{
struct dmar_drhd_unit *drhd;
int ir_supported = 0;
+ int ioapic_idx;
for_each_drhd_unit(drhd) {
struct intel_iommu *iommu = drhd->iommu;
@@ -754,6 +755,16 @@ int __init parse_ioapics_under_ir(void)
return -1;
}
+ for (ioapic_idx = 0; ioapic_idx < nr_ioapics; ioapic_idx++) {
+ int ioapic_id = mpc_ioapic_id(ioapic_idx);
+ if (!map_ioapic_to_ir(ioapic_id)) {
+ pr_err(FW_BUG "ioapic %d has no mapping iommu, "
+ "interrupt remapping will be disabled\n",
+ ioapic_id);
+ return -1;
+ }
+ }
+
return ir_supported;
}
--
1.7.9.5
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