diff options
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 11 | ||||
| -rw-r--r-- | drivers/iommu/intel/Kconfig | 1 | ||||
| -rw-r--r-- | drivers/iommu/intel/iommu.c | 5 |
3 files changed, 11 insertions, 6 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 19192b39952a..87d46cb76121 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1946,11 +1946,12 @@ By default, super page will be supported if Intel IOMMU has the capability. With this option, super page will not be supported. - sm_on [Default Off] - By default, scalable mode will be disabled even if the - hardware advertises that it has support for the scalable - mode translation. With this option set, scalable mode - will be used on hardware which claims to support it. + sm_on + Enable the Intel IOMMU scalable mode if the hardware + advertises that it has support for the scalable mode + translation. + sm_off + Disallow use of the Intel IOMMU scalable mode. tboot_noforce [Default Off] Do not force the Intel IOMMU enabled under tboot. By default, tboot will force Intel IOMMU on, which diff --git a/drivers/iommu/intel/Kconfig b/drivers/iommu/intel/Kconfig index c1a92c3049d0..0ddb77115be7 100644 --- a/drivers/iommu/intel/Kconfig +++ b/drivers/iommu/intel/Kconfig @@ -84,6 +84,7 @@ config INTEL_IOMMU_FLOPPY_WA config INTEL_IOMMU_SCALABLE_MODE_DEFAULT_ON bool "Enable Intel IOMMU scalable mode by default" + default y help Selecting this option will enable by default the scalable mode if hardware presents the capability. The scalable mode is defined in diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index acb91ddf32d0..8c9a9ed7dc09 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -432,8 +432,11 @@ static int __init intel_iommu_setup(char *str) pr_info("Disable supported super page\n"); intel_iommu_superpage = 0; } else if (!strncmp(str, "sm_on", 5)) { - pr_info("Intel-IOMMU: scalable mode supported\n"); + pr_info("Enable scalable mode if hardware supports\n"); intel_iommu_sm = 1; + } else if (!strncmp(str, "sm_off", 6)) { + pr_info("Scalable mode is disallowed\n"); + intel_iommu_sm = 0; } else if (!strncmp(str, "tboot_noforce", 13)) { pr_info("Intel-IOMMU: not forcing on after tboot. This could expose security risk for tboot\n"); intel_iommu_tboot_noforce = 1; |