path: root/drivers/pci/intel-iommu.c
diff options
authorDan Williams <dan.j.williams@intel.com>2010-07-23 15:47:56 -0700
committerDan Williams <dan.j.williams@intel.com>2010-08-04 14:18:17 -0700
commit556ab45f9a775bfa4762bacc0a4afb5b44b067bc (patch)
tree6caf3f7c72617d50d78c4197b872fd0a22b18c99 /drivers/pci/intel-iommu.c
parent128f904ac87cb6e63921e80f378fdf9ba532c0f6 (diff)
ioat2: catch and recover from broken vtd configurations v6
On some platforms (MacPro3,1) the BIOS assigns the ioatdma device to the incorrect iommu causing faults when the driver initializes. Add a quirk to catch this misconfiguration and try falling back to untranslated operation (which works in the MacPro3,1 case). Assuming there are other platforms with misconfigured iommus teach the ioatdma driver to treat initialization failures as non-fatal (just fail the driver load and emit a warning instead of triggering a BUG_ON). This can be classified as a boot regression since 2.6.32 on affected platforms since the ioatdma module did not autoload prior to that kernel. Cc: <stable@kernel.org> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Reported-by: Chris Li <lkml@chrisli.org> Tested-by: Chris Li <lkml@chrisli.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/pci/intel-iommu.c')
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 796828fce34c..90938c7a74c1 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -3029,6 +3029,34 @@ static void __init iommu_exit_mempool(void)
+static void quirk_ioat_snb_local_iommu(struct pci_dev *pdev)
+ struct dmar_drhd_unit *drhd;
+ u32 vtbar;
+ int rc;
+ /* We know that this device on this chipset has its own IOMMU.
+ * If we find it under a different IOMMU, then the BIOS is lying
+ * to us. Hope that the IOMMU for this device is actually
+ * disabled, and it needs no translation...
+ */
+ rc = pci_bus_read_config_dword(pdev->bus, PCI_DEVFN(0, 0), 0xb0, &vtbar);
+ if (rc) {
+ /* "can't" happen */
+ dev_info(&pdev->dev, "failed to run vt-d quirk\n");
+ return;
+ }
+ vtbar &= 0xffff0000;
+ /* we know that the this iommu should be at offset 0xa000 from vtbar */
+ drhd = dmar_find_matched_drhd_unit(pdev);
+ if (WARN_TAINT_ONCE(!drhd || drhd->reg_base_addr - vtbar != 0xa000,
+ "BIOS assigned incorrect VT-d unit for Intel(R) QuickData Technology device\n"))
+ pdev->dev.archdata.iommu = DUMMY_DEVICE_DOMAIN_INFO;
static void __init init_no_remapping_devices(void)
struct dmar_drhd_unit *drhd;