diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index df5c62ecf942b..0edf6084dc148 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4551,6 +4551,8 @@ static bool intel_iommu_capable(enum iommu_cap cap)
 		return domain_update_iommu_snooping(NULL);
 	if (cap == IOMMU_CAP_INTR_REMAP)
 		return irq_remapping_enabled == 1;
+	if (cap == IOMMU_CAP_PRE_BOOT_PROTECTION)
+		return dmar_platform_optin();
 
 	return false;
 }
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index e26cf84e5d82d..4123693ae319e 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -107,6 +107,8 @@ enum iommu_cap {
 					   transactions */
 	IOMMU_CAP_INTR_REMAP,		/* IOMMU supports interrupt isolation */
 	IOMMU_CAP_NOEXEC,		/* IOMMU_NOEXEC flag */
+	IOMMU_CAP_PRE_BOOT_PROTECTION,	/* Firmware says it used the IOMMU for
+					   DMA protection and we should too */
 };
 
 /* These are the possible reserved region types */