intel-iommu: Add Kconfig option to exclude iGPU by default

Bug-Debian: https://bugs.debian.org/935270
Bug-Kali: https://bugs.kali.org/view.php?id=5644

There is still laptop firmware that touches the integrated GPU behind
the operating system's back, and doesn't say so in the RMRR table.
Enabling the IOMMU for all devices causes breakage.

Replace CONFIG_INTEL_IOMMU_DEFAULT_ON with a 3-way choice
corresponding to "on", "off", and "on,intgpu_off".

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Gbp-Pq: Topic features/x86
Gbp-Pq: Name intel-iommu-add-kconfig-option-to-exclude-igpu-by-default.patch

diff --git a/drivers/iommu/intel/Kconfig b/drivers/iommu/intel/Kconfig
index 012cd2541a68a62b8360591f2c680fe14104eec1..823f58ad23d5447e365420f06b1e7218b0183a2a 100644 (file)
--- a/drivers/iommu/intel/Kconfig
+++ b/drivers/iommu/intel/Kconfig
@@ -56,14 +56,25 @@ config INTEL_IOMMU_SVM
          to access DMA resources through process address space by
          means of a Process Address Space ID (PASID).
 
-config INTEL_IOMMU_DEFAULT_ON
-       bool "Enable Intel DMA Remapping Devices by default"
-       default y
+choice
+       prompt "Default state of Intel DMA Remapping Devices"
+       default INTEL_IOMMU_DEFAULT_ON
        help
-         Selecting this option will enable a DMAR device at boot time if
-         one is found. If this option is not selected, DMAR support can
-         be enabled by passing intel_iommu=on to the kernel.
+         Choose whether Intel DMA Remapping Devices should be enabled
+         by default. This can be overridden at boot time using the
+         intel_iommu= kernel parameter.
+
+config INTEL_IOMMU_DEFAULT_ON
+       bool "Enable"
+
+config INTEL_IOMMU_DEFAULT_ON_INTGPU_OFF
+       bool "Enable, excluding integrated GPU"
+
+config INTEL_IOMMU_DEFAULT_OFF
+       bool "Disable"
 
+endchoice
+ 
 config INTEL_IOMMU_BROKEN_GFX_WA
        bool "Workaround broken graphics drivers (going away soon)"
        depends on BROKEN && X86

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 14bad40d80ffbf2cbacfea248d402a76d5667c5a..a01fae256411821867864ad6ee0a96903cfb9571 100644 (file)
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -287,14 +287,14 @@ static LIST_HEAD(dmar_satc_units);
 
 static void intel_iommu_domain_free(struct iommu_domain *domain);
 
-int dmar_disabled = !IS_ENABLED(CONFIG_INTEL_IOMMU_DEFAULT_ON);
+int dmar_disabled = IS_ENABLED(CONFIG_INTEL_IOMMU_DEFAULT_OFF);
 int intel_iommu_sm = IS_ENABLED(CONFIG_INTEL_IOMMU_SCALABLE_MODE_DEFAULT_ON);
 
 int intel_iommu_enabled = 0;
 EXPORT_SYMBOL_GPL(intel_iommu_enabled);
 
 static int dmar_map_gfx = 1;
-static int dmar_map_intgpu = 1;
+static int dmar_map_intgpu = IS_ENABLED(CONFIG_INTEL_IOMMU_DEFAULT_ON);
 static int intel_iommu_superpage = 1;
 static int iommu_identity_mapping;
 static int iommu_skip_te_disable;
@@ -333,6 +333,7 @@ static int __init intel_iommu_setup(char *str)
        while (*str) {
                if (!strncmp(str, "on", 2)) {
                        dmar_disabled = 0;
+                       dmar_map_intgpu = 1;
                        pr_info("IOMMU enabled\n");
                } else if (!strncmp(str, "off", 3)) {
                        dmar_disabled = 1;