Re: [PATCH v14 4/6] iommu/vt-d: Add support for IOMMU default DMA mode build options

From: Zhen Lei <redacted>

Make IOMMU_DEFAULT_LAZY default for when INTEL_IOMMU config is set,
as is current behaviour.

Also delete global flag intel_iommu_strict:
- In intel_iommu_setup(), call iommu_set_dma_strict(true) directly. Also
   remove the print, as iommu_subsys_init() prints the mode and we have
   already marked this param as deprecated.

- For cap_caching_mode() check in intel_iommu_setup(), call
   iommu_set_dma_strict(true) directly; also reword the accompanying print
   with a level downgrade and also add the missing '\n'.

- For Ironlake GPU, again call iommu_set_dma_strict(true) directly and
   keep the accompanying print.

[jpg: Remove intel_iommu_strict]
Signed-off-by: Zhen Lei <redacted>
Signed-off-by: John Garry <redacted>
---
  drivers/iommu/Kconfig       |  1 +
  drivers/iommu/intel/iommu.c | 15 ++++++---------
  2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 0327a942fdb7..c214a36eb2dc 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig

@@ -94,6 +94,7 @@ choice
  	prompt "IOMMU default DMA IOTLB invalidation mode"
  	depends on IOMMU_DMA
  
+	default IOMMU_DEFAULT_LAZY if INTEL_IOMMU
  	default IOMMU_DEFAULT_STRICT
  	help
  	  This option allows an IOMMU DMA IOTLB invalidation mode to be

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 29497113d748..06666f9d8116 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c

@@ -361,7 +361,6 @@ int intel_iommu_enabled = 0;
  EXPORT_SYMBOL_GPL(intel_iommu_enabled);
  
  static int dmar_map_gfx = 1;
-static int intel_iommu_strict;
  static int intel_iommu_superpage = 1;
  static int iommu_identity_mapping;
  static int iommu_skip_te_disable;

@@ -455,8 +454,7 @@ static int __init intel_iommu_setup(char *str)
  			iommu_dma_forcedac = true;
  		} else if (!strncmp(str, "strict", 6)) {
  			pr_warn("intel_iommu=strict deprecated; use iommu.strict=1 instead\n");
-			pr_info("Disable batched IOTLB flush\n");
-			intel_iommu_strict = 1;
+			iommu_set_dma_strict(true);
  		} else if (!strncmp(str, "sp_off", 6)) {
  			pr_info("Disable supported super page\n");
  			intel_iommu_superpage = 0;

@@ -4382,9 +4380,9 @@ int __init intel_iommu_init(void)
  		 * is likely to be much lower than the overhead of synchronizing
  		 * the virtual and physical IOMMU page-tables.
  		 */
-		if (!intel_iommu_strict && cap_caching_mode(iommu->cap)) {
-			pr_warn("IOMMU batching is disabled due to virtualization");
-			intel_iommu_strict = 1;
+		if (cap_caching_mode(iommu->cap)) {
+			pr_info_once("IOMMU batching disallowed due to virtualization\n");
+			iommu_set_dma_strict(true);
  		}
  		iommu_device_sysfs_add(&iommu->iommu, NULL,
  				       intel_iommu_groups,

@@ -4393,7 +4391,6 @@ int __init intel_iommu_init(void)
  	}
  	up_read(&dmar_global_lock);
  
-	iommu_set_dma_strict(intel_iommu_strict);
  	bus_set_iommu(&pci_bus_type, &intel_iommu_ops);
  	if (si_domain && !hw_pass_through)
  		register_memory_notifier(&intel_iommu_memory_nb);

@@ -5702,8 +5699,8 @@ static void quirk_calpella_no_shadow_gtt(struct pci_dev *dev)
  	} else if (dmar_map_gfx) {
  		/* we have to ensure the gfx device is idle before we flush */
  		pci_info(dev, "Disabling batched IOTLB flush on Ironlake\n");
-		intel_iommu_strict = 1;
-       }
+		iommu_set_dma_strict(true);
+	}
  }
  DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x0040, quirk_calpella_no_shadow_gtt);
  DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x0044, quirk_calpella_no_shadow_gtt);