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authorLu Baolu <baolu.lu@linux.intel.com>2021-08-18 21:48:47 +0800
committerJoerg Roedel <jroedel@suse.de>2021-08-19 10:41:08 +0200
commit792fb43ce2c98878f1539c1d3fdecc1d7a7d78fd (patch)
treef2a9e8aa1379f84db4d2bb636e5f591529c166d6 /drivers/iommu
parent01dac2d9d2364d2a68b37cc1381947ca53413b51 (diff)
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>
Diffstat (limited to 'drivers/iommu')
-rw-r--r--drivers/iommu/intel/Kconfig1
-rw-r--r--drivers/iommu/intel/iommu.c5
2 files changed, 5 insertions, 1 deletions
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;