On Tue, Aug 7, 2012 at 2:39 PM, Seth Forshee <seth.forshee@xxxxxxxxxxxxx> wrote:
> 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 <suresh.b.siddha@xxxxxxxxx>
> Signed-off-by: Seth Forshee <seth.forshee@xxxxxxxxxxxxx>
> ---
> 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;
> }
>
need to add
if (ir_supported)
> + 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;
> + }
> + }
> +
otherwise may false warning.
> return ir_supported;
> }
also could remove the ir_ioapic_num == nr_ioapics checking.
Thanks
Yinghai
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