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path: root/drivers/iommu/intel-iommu.c
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Diffstat (limited to 'drivers/iommu/intel-iommu.c')
-rw-r--r--drivers/iommu/intel-iommu.c36
1 files changed, 35 insertions, 1 deletions
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index d412a313a372..90ab0115d78e 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -183,6 +183,7 @@ static int rwbf_quirk;
* (used when kernel is launched w/ TXT)
*/
static int force_on = 0;
+int intel_iommu_tboot_noforce;
/*
* 0: Present
@@ -607,6 +608,10 @@ static int __init intel_iommu_setup(char *str)
"Intel-IOMMU: enable pre-production PASID support\n");
intel_iommu_pasid28 = 1;
iommu_identity_mapping |= IDENTMAP_GFX;
+ } else if (!strncmp(str, "tboot_noforce", 13)) {
+ printk(KERN_INFO
+ "Intel-IOMMU: not forcing on after tboot. This could expose security risk for tboot\n");
+ intel_iommu_tboot_noforce = 1;
}
str += strcspn(str, ",");
@@ -4730,6 +4735,15 @@ static int intel_iommu_cpu_dead(unsigned int cpu)
return 0;
}
+static void intel_disable_iommus(void)
+{
+ struct intel_iommu *iommu = NULL;
+ struct dmar_drhd_unit *drhd;
+
+ for_each_iommu(iommu, drhd)
+ iommu_disable_translation(iommu);
+}
+
static inline struct intel_iommu *dev_to_intel_iommu(struct device *dev)
{
return container_of(dev, struct intel_iommu, iommu.dev);
@@ -4840,8 +4854,28 @@ int __init intel_iommu_init(void)
goto out_free_dmar;
}
- if (no_iommu || dmar_disabled)
+ if (no_iommu || dmar_disabled) {
+ /*
+ * We exit the function here to ensure IOMMU's remapping and
+ * mempool aren't setup, which means that the IOMMU's PMRs
+ * won't be disabled via the call to init_dmars(). So disable
+ * it explicitly here. The PMRs were setup by tboot prior to
+ * calling SENTER, but the kernel is expected to reset/tear
+ * down the PMRs.
+ */
+ if (intel_iommu_tboot_noforce) {
+ for_each_iommu(iommu, drhd)
+ iommu_disable_protect_mem_regions(iommu);
+ }
+
+ /*
+ * Make sure the IOMMUs are switched off, even when we
+ * boot into a kexec kernel and the previous kernel left
+ * them enabled
+ */
+ intel_disable_iommus();
goto out_free_dmar;
+ }
if (list_empty(&dmar_rmrr_units))
pr_info("No RMRR found\n");