diff options
Diffstat (limited to 'drivers/iommu/intel-iommu.c')
| -rw-r--r-- | drivers/iommu/intel-iommu.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 5f08ba13972b..b0ced1c13713 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, ","); @@ -4851,6 +4856,19 @@ int __init intel_iommu_init(void) 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 |