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irq_remap: disable IRQ remapping if any IOAPIC lacks an IOMMU

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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 <suresh.b.siddha@intel.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This commit is contained in:
Seth Forshee 2012-08-08 08:27:03 -05:00 committed by Joerg Roedel
parent 31fe943599
commit 32ab31e01e
1 changed files with 13 additions and 5 deletions
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18
drivers/iommu/intel_irq_remapping.c
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@ -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;
@ -748,13 +749,20 @@ int __init parse_ioapics_under_ir(void)
}
}
if (ir_supported && ir_ioapic_num != nr_ioapics) {
printk(KERN_WARNING
"Not all IO-APIC's listed under remapping hardware\n");
return -1;
if (!ir_supported)
return 0;
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;
return 1;
}
int __init ir_dev_scope_init(void)