iommu: remove DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE

Instead make the global iommu_dma_strict paramete in iommu.c canonical by
exporting helpers to get and set it and use those directly in the drivers.

This make sure that the iommu.strict parameter also works for the AMD and
Intel IOMMU drivers on x86.  As those default to lazy flushing a new
IOMMU_CMD_LINE_STRICT is used to turn the value into a tristate to
represent the default if not overriden by an explicit parameter.

[ported on top of the other iommu_attr changes and added a few small
 missing bits]

Signed-off-by: Robin Murphy <robin.murphy@arm.com>.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210401155256.298656-19-hch@lst.de
Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 12 insertions, 52 deletions

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 761feac91767..1db4d8934526 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4347,6 +4347,17 @@ int __init intel_iommu_init(void)
 
 	down_read(&dmar_global_lock);
 	for_each_active_iommu(iommu, drhd) {
+		/*
+		 * The flush queue implementation does not perform
+		 * page-selective invalidations that are required for efficient
+		 * TLB flushes in virtual environments.  The benefit of batching
+		 * 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;
+		}
 		iommu_device_sysfs_add(&iommu->iommu, NULL,
 				       intel_iommu_groups,
 				       "%s", iommu->name);
@@ -4355,6 +4366,7 @@ 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);
@@ -5413,57 +5425,6 @@ intel_iommu_enable_nesting(struct iommu_domain *domain)
 	return ret;
 }
 
-static bool domain_use_flush_queue(void)
-{
-	struct dmar_drhd_unit *drhd;
-	struct intel_iommu *iommu;
-	bool r = true;
-
-	if (intel_iommu_strict)
-		return false;
-
-	/*
-	 * The flush queue implementation does not perform page-selective
-	 * invalidations that are required for efficient TLB flushes in virtual
-	 * environments. The benefit of batching is likely to be much lower than
-	 * the overhead of synchronizing the virtual and physical IOMMU
-	 * page-tables.
-	 */
-	rcu_read_lock();
-	for_each_active_iommu(iommu, drhd) {
-		if (!cap_caching_mode(iommu->cap))
-			continue;
-
-		pr_warn_once("IOMMU batching is disabled due to virtualization");
-		r = false;
-		break;
-	}
-	rcu_read_unlock();
-
-	return r;
-}
-
-static int
-intel_iommu_domain_get_attr(struct iommu_domain *domain,
-			    enum iommu_attr attr, void *data)
-{
-	switch (domain->type) {
-	case IOMMU_DOMAIN_UNMANAGED:
-		return -ENODEV;
-	case IOMMU_DOMAIN_DMA:
-		switch (attr) {
-		case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE:
-			*(int *)data = domain_use_flush_queue();
-			return 0;
-		default:
-			return -ENODEV;
-		}
-		break;
-	default:
-		return -EINVAL;
-	}
-}
-
 /*
  * Check that the device does not live on an external facing PCI port that is
  * marked as untrusted. Such devices should not be able to apply quirks and
@@ -5536,7 +5497,6 @@ const struct iommu_ops intel_iommu_ops = {
 	.capable		= intel_iommu_capable,
 	.domain_alloc		= intel_iommu_domain_alloc,
 	.domain_free		= intel_iommu_domain_free,
-	.domain_get_attr        = intel_iommu_domain_get_attr,
 	.enable_nesting		= intel_iommu_enable_nesting,
 	.attach_dev		= intel_iommu_attach_device,
 	.detach_dev		= intel_iommu_detach_device,