diff options
Diffstat (limited to 'drivers/iommu/intel-iommu.c')
| -rw-r--r-- | drivers/iommu/intel-iommu.c | 36 |
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"); |