Applied: [Quantal][PATCH 1/1] UBUNTU: SAUCE: (drop after 3.6) irq_remap: disable IRQ remapping if any IOAPIC lacks an IOMMU

[Leann Ogasawara]

Applied to Quantal master-next.

Thanks,
Leann

On 08/10/2012 02:25 PM, Seth Forshee 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
> 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 at intel.com>
> Signed-off-by: Seth Forshee <seth.forshee at canonical.com>
> Acked-by: Yinghai Lu <yinghai at kernel.org>
> Signed-off-by: Joerg Roedel <joerg.roedel at amd.com>
> (cherry picked from commit 32ab31e01e2def6f48294d872d9bb42573aae00f
>  git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git)
> BugLink: http://bugs.launchpad.net/bugs/1034459
> ---
>  drivers/iommu/intel_irq_remapping.c |   18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
> index 6d34706..55fe60d 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;
> @@ -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)