Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'iommu-fixes-v5.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu
Pull IOMMU fix from Joerg Roedel:
"Intel decided to leave the newly added Scalable Mode Feature
default-disabled for now. The patch here accomplishes that"
* tag 'iommu-fixes-v5.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
iommu/vt-d: Leave scalable mode default off
+7
-8
+3
-4
Documentation/admin-guide/kernel-parameters.txt
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-4
Documentation/admin-guide/kernel-parameters.txt
···
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By default, super page will be supported if Intel IOMMU
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has the capability. With this option, super page will
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not be supported.
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-
sm_off [Default Off]
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-
By default, scalable mode will be supported if the
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+
sm_on [Default Off]
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+
By default, scalable mode will be disabled even if the
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hardware advertises that it has support for the scalable
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mode translation. With this option set, scalable mode
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-
will not be used even on hardware which claims to support
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-
it.
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+
will be used on hardware which claims to support it.
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tboot_noforce [Default Off]
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Do not force the Intel IOMMU enabled under tboot.
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By default, tboot will force Intel IOMMU on, which
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-4
drivers/iommu/intel-iommu.c
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-4
drivers/iommu/intel-iommu.c
···
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static int dmar_forcedac;
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static int intel_iommu_strict;
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static int intel_iommu_superpage = 1;
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-
static int intel_iommu_sm = 1;
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+
static int intel_iommu_sm;
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static int iommu_identity_mapping;
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#define IDENTMAP_ALL 1
···
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} else if (!strncmp(str, "sp_off", 6)) {
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pr_info("Disable supported super page\n");
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intel_iommu_superpage = 0;
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-
} else if (!strncmp(str, "sm_off", 6)) {
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pr_info("Intel-IOMMU: disable scalable mode support\n");
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-
intel_iommu_sm = 0;
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+
} else if (!strncmp(str, "sm_on", 5)) {
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pr_info("Intel-IOMMU: scalable mode supported\n");
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+
intel_iommu_sm = 1;
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} else if (!strncmp(str, "tboot_noforce", 13)) {
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printk(KERN_INFO
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"Intel-IOMMU: not forcing on after tboot. This could expose security risk for tboot\n");