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| author | Lu Baolu <baolu.lu@linux.intel.com> | 2021-08-18 15:48:47 +0200 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2021-08-19 10:41:08 +0200 |
| commit | 792fb43ce2c98878f1539c1d3fdecc1d7a7d78fd (patch) | |
| tree | f2a9e8aa1379f84db4d2bb636e5f591529c166d6 | |
| parent | iommu/vt-d: Refactor Kconfig a bit (diff) | |
| download | linux-792fb43ce2c98878f1539c1d3fdecc1d7a7d78fd.tar.xz linux-792fb43ce2c98878f1539c1d3fdecc1d7a7d78fd.zip | |
iommu/vt-d: Enable Intel IOMMU scalable mode by default
The commit 8950dcd83ae7d ("iommu/vt-d: Leave scalable mode default off")
leaves the scalable mode default off and end users could turn it on with
"intel_iommu=sm_on". Using the Intel IOMMU scalable mode for kernel DMA,
user-level device access and Shared Virtual Address have been enabled.
This enables the scalable mode by default if the hardware advertises the
support and adds kernel options of "intel_iommu=sm_on/sm_off" for end
users to configure it through the kernel parameters.
Suggested-by: Ashok Raj <ashok.raj@intel.com>
Suggested-by: Sanjay Kumar <sanjay.k.kumar@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20210720013856.4143880-1-baolu.lu@linux.intel.com
Link: https://lore.kernel.org/r/20210818134852.1847070-5-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
| -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; |