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 <David.Woodhouse@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 8d0e60a..c3edcdc 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -2348,11 +2348,34 @@
}
+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;
}
}