From cbda1ba898647aeb4ee770b803c922f595e97731 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Sun, 7 Sep 2008 16:35:26 +0100 Subject: [PATCH] PCI/iommu: blacklist DMAR on Intel G31/G33 chipsets Some BIOSes (the Intel DG33BU, for example) wrongly claim to have DMAR when they don't. Avoid the resulting crashes when it doesn't work as expected. Signed-off-by: David Woodhouse Acked-by: Ingo Molnar Signed-off-by: Jesse Barnes --- drivers/pci/intel-iommu.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c index 8d0e60ac849..c3edcdc08e7 100644 --- a/drivers/pci/intel-iommu.c +++ b/drivers/pci/intel-iommu.c @@ -2348,11 +2348,34 @@ static void __init iommu_exit_mempool(void) } +static int blacklist_iommu(const struct dmi_system_id *id) +{ + printk(KERN_INFO "%s detected; disabling IOMMU\n", + id->ident); + dmar_disabled = 1; + return 0; +} + +static struct dmi_system_id __initdata intel_iommu_dmi_table[] = { + { /* Some DG33BU BIOS revisions advertised non-existent VT-d */ + .callback = blacklist_iommu, + .ident = "Intel DG33BU", + { DMI_MATCH(DMI_BOARD_VENDOR, "Intel Corporation"), + DMI_MATCH(DMI_BOARD_NAME, "DG33BU"), + } + }, + { } +}; + + void __init detect_intel_iommu(void) { if (swiotlb || no_iommu || iommu_detected || dmar_disabled) return; if (early_dmar_detect()) { + dmi_check_system(intel_iommu_dmi_table); + if (dmar_disabled) + return; iommu_detected = 1; } } -- 2.20.1