patches/kernel/0009-allow-opt-in-to-allow-pass-through-on-broken-hardwar.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: kiler129 <grzegorz@noflash.pl>
   3 Date: Mon, 18 Sep 2023 15:19:26 +0200
   4 Subject: [PATCH] allow opt-in to allow pass-through on broken hardware..
   5
   6 adapted from https://github.com/kiler129/relax-intel-rmrr , licensed under MIT or GPL 2.0+
   7
   8 Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
   9 ---
  10  drivers/iommu/intel/iommu.c | 6 +++++-
  11  1 file changed, 5 insertions(+), 1 deletion(-)
  12
  13 diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
  14 index a377f8e0a414..3be334d34317 100644
  15 --- a/drivers/iommu/intel/iommu.c
  16 +++ b/drivers/iommu/intel/iommu.c
  17 @@ -298,6 +298,7 @@ static int dmar_map_gfx = 1;
  18  static int dmar_map_ipu = 1;
  19  static int intel_iommu_superpage = 1;
  20  static int iommu_identity_mapping;
  21 +static int intel_relaxable_rmrr = 0;
  22  static int iommu_skip_te_disable;
  23
  24  #define IDENTMAP_GFX           2
  25 @@ -359,6 +360,9 @@ static int __init intel_iommu_setup(char *str)
  26                 } else if (!strncmp(str, "tboot_noforce", 13)) {
  27                         pr_info("Intel-IOMMU: not forcing on after tboot. This could expose security risk for tboot\n");
  28                         intel_iommu_tboot_noforce = 1;
  29 +               } else if (!strncmp(str, "relax_rmrr", 10)) {
  30 +                       pr_info("Intel-IOMMU: assuming all RMRRs are relaxable. This can lead to instability or data loss\n");
  31 +                       intel_relaxable_rmrr = 1;
  32                 } else {
  33                         pr_notice("Unknown option - '%s'\n", str);
  34                 }
  35 @@ -2503,7 +2507,7 @@ static bool device_rmrr_is_relaxable(struct device *dev)
  36                 return false;
  37
  38         pdev = to_pci_dev(dev);
  39 -       if (IS_USB_DEVICE(pdev) || IS_GFX_DEVICE(pdev))
  40 +       if (intel_relaxable_rmrr || IS_USB_DEVICE(pdev) || IS_GFX_DEVICE(pdev))
  41                 return true;
  42         else
  43                 return false;