From: Seth Forshee Subject: irq_remap: disable IRQ remapping if any IOAPIC lacks an IOMMU Git-commit: 32ab31e01e2def6f48294d872d9bb42573aae00f Patch-mainline: v3.6-rc3~25^2~1 References: Date: Wed, 8 Aug 2012 08:27:03 -0500 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 Signed-off-by: Seth Forshee Acked-by: Yinghai Lu Signed-off-by: Joerg Roedel Acked-by: Cho, Yu-Chen --- drivers/iommu/intr_remapping.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) --- a/drivers/iommu/intr_remapping.c +++ b/drivers/iommu/intr_remapping.c @@ -752,6 +752,7 @@ 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; @@ -764,13 +765,20 @@ 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) -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org