Merge tag 'char-misc-4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc driver updates from Greg KH:
 "Here is the big set of char and misc driver patches for 4.21-rc1.

  Lots of different types of driver things in here, as this tree seems
  to be the "collection of various driver subsystems not big enough to
  have their own git tree" lately.

  Anyway, some highlights of the changes in here:

   - binderfs: is it a rule that all driver subsystems will eventually
     grow to have their own filesystem? Binder now has one to handle the
     use of it in containerized systems.

     This was discussed at the Plumbers conference a few months ago and
     knocked into mergable shape very fast by Christian Brauner. Who
     also has signed up to be another binder maintainer, showing a
     distinct lack of good judgement :)

   - binder updates and fixes

   - mei driver updates

   - fpga driver updates and additions

   - thunderbolt driver updates

   - soundwire driver updates

   - extcon driver updates

   - nvmem driver updates

   - hyper-v driver updates

   - coresight driver updates

   - pvpanic driver additions and reworking for more device support

   - lp driver updates. Yes really, it's _finally_ moved to the proper
     parallal port driver model, something I never thought I would see
     happen. Good stuff.

   - other tiny driver updates and fixes.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'char-misc-4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (116 commits)
  MAINTAINERS: add another Android binder maintainer
  intel_th: msu: Fix an off-by-one in attribute store
  stm class: Add a reference to the SyS-T document
  stm class: Fix a module refcount leak in policy creation error path
  char: lp: use new parport device model
  char: lp: properly count the lp devices
  char: lp: use first unused lp number while registering
  char: lp: detach the device when parallel port is removed
  char: lp: introduce list to save port number
  bus: qcom: remove duplicated include from qcom-ebi2.c
  VMCI: Use memdup_user() rather than duplicating its implementation
  char/rtc: Use of_node_name_eq for node name comparisons
  misc: mic: fix a DMA pool free failure
  ptp: fix an IS_ERR() vs NULL check
  genwqe: Fix size check
  binder: implement binderfs
  binder: fix use-after-free due to ksys_close() during fdget()
  bus: fsl-mc: remove duplicated include files
  bus: fsl-mc: explicitly define the fsl_mc_command endianness
  misc: ti-st: make array read_ver_cmd static, shrinks object size
  ...

2 files changed, 78 insertions, 3 deletions

diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index d9c748b6f9e4..1edf2a251336 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -2042,3 +2042,28 @@ int dmar_device_remove(acpi_handle handle)
 {
 	return dmar_device_hotplug(handle, false);
 }
+
+/*
+ * dmar_platform_optin - Is %DMA_CTRL_PLATFORM_OPT_IN_FLAG set in DMAR table
+ *
+ * Returns true if the platform has %DMA_CTRL_PLATFORM_OPT_IN_FLAG set in
+ * the ACPI DMAR table. This means that the platform boot firmware has made
+ * sure no device can issue DMA outside of RMRR regions.
+ */
+bool dmar_platform_optin(void)
+{
+	struct acpi_table_dmar *dmar;
+	acpi_status status;
+	bool ret;
+
+	status = acpi_get_table(ACPI_SIG_DMAR, 0,
+				(struct acpi_table_header **)&dmar);
+	if (ACPI_FAILURE(status))
+		return false;
+
+	ret = !!(dmar->flags & DMAR_PLATFORM_OPT_IN);
+	acpi_put_table((struct acpi_table_header *)dmar);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dmar_platform_optin);
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 0ad67d65bbce..63b6ce78492a 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -184,6 +184,7 @@ static int rwbf_quirk;
  */
 static int force_on = 0;
 int intel_iommu_tboot_noforce;
+static int no_platform_optin;
 
 #define ROOT_ENTRY_NR (VTD_PAGE_SIZE/sizeof(struct root_entry))
 
@@ -503,6 +504,7 @@ static int __init intel_iommu_setup(char *str)
 			pr_info("IOMMU enabled\n");
 		} else if (!strncmp(str, "off", 3)) {
 			dmar_disabled = 1;
+			no_platform_optin = 1;
 			pr_info("IOMMU disabled\n");
 		} else if (!strncmp(str, "igfx_off", 8)) {
 			dmar_map_gfx = 0;
@@ -1471,7 +1473,8 @@ static void iommu_enable_dev_iotlb(struct device_domain_info *info)
 	if (info->pri_supported && !pci_reset_pri(pdev) && !pci_enable_pri(pdev, 32))
 		info->pri_enabled = 1;
 #endif
-	if (info->ats_supported && !pci_enable_ats(pdev, VTD_PAGE_SHIFT)) {
+	if (!pdev->untrusted && info->ats_supported &&
+	    !pci_enable_ats(pdev, VTD_PAGE_SHIFT)) {
 		info->ats_enabled = 1;
 		domain_update_iotlb(info->domain);
 		info->ats_qdep = pci_ats_queue_depth(pdev);
@@ -2895,6 +2898,13 @@ static int iommu_should_identity_map(struct device *dev, int startup)
 		if (device_is_rmrr_locked(dev))
 			return 0;
 
+		/*
+		 * Prevent any device marked as untrusted from getting
+		 * placed into the statically identity mapping domain.
+		 */
+		if (pdev->untrusted)
+			return 0;
+
 		if ((iommu_identity_mapping & IDENTMAP_AZALIA) && IS_AZALIA(pdev))
 			return 1;
 
@@ -4722,14 +4732,54 @@ const struct attribute_group *intel_iommu_groups[] = {
 	NULL,
 };
 
+static int __init platform_optin_force_iommu(void)
+{
+	struct pci_dev *pdev = NULL;
+	bool has_untrusted_dev = false;
+
+	if (!dmar_platform_optin() || no_platform_optin)
+		return 0;
+
+	for_each_pci_dev(pdev) {
+		if (pdev->untrusted) {
+			has_untrusted_dev = true;
+			break;
+		}
+	}
+
+	if (!has_untrusted_dev)
+		return 0;
+
+	if (no_iommu || dmar_disabled)
+		pr_info("Intel-IOMMU force enabled due to platform opt in\n");
+
+	/*
+	 * If Intel-IOMMU is disabled by default, we will apply identity
+	 * map for all devices except those marked as being untrusted.
+	 */
+	if (dmar_disabled)
+		iommu_identity_mapping |= IDENTMAP_ALL;
+
+	dmar_disabled = 0;
+#if defined(CONFIG_X86) && defined(CONFIG_SWIOTLB)
+	swiotlb = 0;
+#endif
+	no_iommu = 0;
+
+	return 1;
+}
+
 int __init intel_iommu_init(void)
 {
 	int ret = -ENODEV;
 	struct dmar_drhd_unit *drhd;
 	struct intel_iommu *iommu;
 
-	/* VT-d is required for a TXT/tboot launch, so enforce that */
-	force_on = tboot_force_iommu();
+	/*
+	 * Intel IOMMU is required for a TXT/tboot launch or platform
+	 * opt in, so enforce that.
+	 */
+	force_on = tboot_force_iommu() || platform_optin_force_iommu();
 
 	if (iommu_init_mempool()) {
 		if (force_on)