diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c index 23a119e6485e..bd2c01674f5e 100644 --- a/drivers/pci/dmar.c +++ b/drivers/pci/dmar.c @@ -457,6 +457,31 @@ void __init detect_intel_iommu(void) #ifdef CONFIG_DMAR { + struct acpi_table_dmar *dmar; + /* + * for now we will disable dma-remapping when interrupt + * remapping is enabled. + * When support for queued invalidation for IOTLB invalidation + * is added, we will not need this any more. + */ + dmar = (struct acpi_table_dmar *) dmar_tbl; + if (ret && cpu_has_x2apic && dmar->flags & 0x1) { + printk(KERN_INFO + "Queued invalidation will be enabled to support " + "x2apic and Intr-remapping.\n"); + printk(KERN_INFO + "Disabling IOMMU detection, because of missing " + "queued invalidation support for IOTLB " + "invalidation\n"); + printk(KERN_INFO + "Use \"nox2apic\", if you want to use Intel " + " IOMMU for DMA-remapping and don't care about " + " x2apic support\n"); + + dmar_disabled = 1; + return; + } + if (ret && !no_iommu && !iommu_detected && !swiotlb && !dmar_disabled) iommu_detected = 1;