patches/kernel/0014-add-relaxable-rmrr.patch

   1 From: kiler129 <grzegorz@noflash.pl>
   2
   3 allow opt-in to allow pass-through on broken hardware..
   4
   5 adapted from https://github.com/kiler129/relax-intel-rmrr , licensed under MIT or GPL 2.0+
   6
   7 --- a/drivers/iommu/intel/iommu.c
   8 +++ b/drivers/iommu/intel/iommu.c
   9 @@ -297,6 +297,7 @@
  10  static int dmar_map_ipu = 1;
  11  static int intel_iommu_superpage = 1;
  12  static int iommu_identity_mapping;
  13 +static int intel_relaxable_rmrr = 0;
  14  static int iommu_skip_te_disable;
  15
  16  #define IDENTMAP_GFX           2
  17 @@ -358,6 +359,9 @@
  18                 } else if (!strncmp(str, "tboot_noforce", 13)) {
  19                         pr_info("Intel-IOMMU: not forcing on after tboot. This could expose security risk for tboot\n");
  20                         intel_iommu_tboot_noforce = 1;
  21 +               } else if (!strncmp(str, "relax_rmrr", 10)) {
  22 +                       pr_info("Intel-IOMMU: assuming all RMRRs are relaxable. This can lead to instability or data loss\n");
  23 +                       intel_relaxable_rmrr = 1;
  24                 } else {
  25                         pr_notice("Unknown option - '%s'\n", str);
  26                 }
  27 @@ -2538,7 +2542,7 @@
  28                 return false;
  29
  30         pdev = to_pci_dev(dev);
  31 -       if (IS_USB_DEVICE(pdev) || IS_GFX_DEVICE(pdev))
  32 +       if (intel_relaxable_rmrr || IS_USB_DEVICE(pdev) || IS_GFX_DEVICE(pdev))
  33                 return true;
  34         else
  35                 return false;