[PATCH v3 6/8] iommu/vt-d: Allow DMA domains to be allocated by iommu ops

[Lu Baolu <baolu.lu@linux.intel.com>]

From: James Sewart <jamessewart@arista.com>

Allowing IOMMU_DOMAIN_DMA and IOMMU_DOMAIN_IDENTITY types of
domains to be allocated through iommu ops allows the default
domain of an iommu_group to be set. This delegates domains of
Intel IOMMU driver to the generic IOMMU layer.

Signed-off-by: James Sewart <jamessewart@arista.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel-iommu.c | 124 ++++++++++++++++++++++++++----------
 1 file changed, 90 insertions(+), 34 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index d2b51e045603..ec6ac39827ab 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -311,6 +311,12 @@ static int hw_pass_through = 1;
 /* si_domain contains mulitple devices */
 #define DOMAIN_FLAG_STATIC_IDENTITY	(1 << 1)
 
+/*
+ * Domain managed externally, don't cleanup if it isn't attached
+ * to any devices.
+ */
+#define DOMAIN_FLAG_MANAGED_EXTERNALLY	(1 << 2)
+
 #define for_each_domain_iommu(idx, domain)			\
 	for (idx = 0; idx < g_num_of_iommus; idx++)		\
 		if (domain->iommu_refcnt[idx])
@@ -561,6 +567,11 @@ static inline int domain_type_is_vm_or_si(struct dmar_domain *domain)
 				DOMAIN_FLAG_STATIC_IDENTITY);
 }
 
+static inline int domain_managed_externally(struct dmar_domain *domain)
+{
+	return domain->flags & DOMAIN_FLAG_MANAGED_EXTERNALLY;
+}
+
 static inline int domain_pfn_supported(struct dmar_domain *domain,
 				       unsigned long pfn)
 {
@@ -1671,7 +1682,7 @@ static void disable_dmar_iommu(struct intel_iommu *iommu)
 
 		__dmar_remove_one_dev_info(info);
 
-		if (!domain_type_is_vm_or_si(domain)) {
+		if (!domain_managed_externally(domain)) {
 			/*
 			 * The domain_exit() function  can't be called under
 			 * device_domain_lock, as it takes this lock itself.
@@ -2366,7 +2377,12 @@ static int domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
 	} else {
 		/* General domains only have one IOMMU */
 		iommu = domain_get_iommu(domain);
-		__mapping_notify_one(iommu, domain, iov_pfn, nr_pages);
+		/*
+		 * There's no associated iommu if domain hasn't been attached
+		 * to any device yet.
+		 */
+		if (iommu)
+			__mapping_notify_one(iommu, domain, iov_pfn, nr_pages);
 	}
 
 	return 0;
@@ -3406,12 +3422,9 @@ static int __init init_dmars(void)
 
 	check_tylersburg_isoch();
 
-	if (iommu_identity_mapping) {
-		ret = si_domain_init(hw_pass_through);
-		if (ret)
-			goto free_iommu;
-	}
-
+	ret = si_domain_init(hw_pass_through);
+	if (ret)
+		goto free_iommu;
 
 	/*
 	 * If we copied translations from a previous kernel in the kdump
@@ -4572,7 +4585,7 @@ static int device_notifier(struct notifier_block *nb,
 			return 0;
 
 		dmar_remove_one_dev_info(dev);
-		if (!domain_type_is_vm_or_si(domain) &&
+		if (!domain_managed_externally(domain) &&
 		    list_empty(&domain->devices))
 			domain_exit(domain);
 	} else if (action == BUS_NOTIFY_ADD_DEVICE) {
@@ -5038,33 +5051,52 @@ static struct iommu_domain *intel_iommu_domain_alloc(unsigned type)
 {
 	struct dmar_domain *dmar_domain;
 	struct iommu_domain *domain;
+	int flags = DOMAIN_FLAG_MANAGED_EXTERNALLY;
 
-	if (type != IOMMU_DOMAIN_UNMANAGED)
-		return NULL;
+	switch (type) {
+	case IOMMU_DOMAIN_UNMANAGED:
+		flags |= DOMAIN_FLAG_VIRTUAL_MACHINE;
+		/* fall through */
+	case IOMMU_DOMAIN_DMA:
+		dmar_domain = alloc_domain(flags);
+		if (!dmar_domain)
+			return NULL;
 
-	dmar_domain = alloc_domain(DOMAIN_FLAG_VIRTUAL_MACHINE);
-	if (!dmar_domain) {
-		pr_err("Can't allocate dmar_domain\n");
-		return NULL;
-	}
-	if (md_domain_init(dmar_domain, DEFAULT_DOMAIN_ADDRESS_WIDTH)) {
-		pr_err("Domain initialization failed\n");
-		domain_exit(dmar_domain);
+		if (md_domain_init(dmar_domain, DEFAULT_DOMAIN_ADDRESS_WIDTH)) {
+			pr_err("Domain initialization failed\n");
+			domain_exit(dmar_domain);
+			return NULL;
+		}
+
+		if (type == IOMMU_DOMAIN_DMA &&
+		    init_iova_flush_queue(&dmar_domain->iovad,
+					  iommu_flush_iova, iova_entry_free)) {
+			pr_warn("iova flush queue initialization failed\n");
+			intel_iommu_strict = 1;
+		}
+
+		domain_update_iommu_cap(dmar_domain);
+		domain = &dmar_domain->domain;
+		domain->geometry.aperture_start = 0;
+		domain->geometry.aperture_end =
+			__DOMAIN_MAX_ADDR(dmar_domain->gaw);
+		domain->geometry.force_aperture = true;
+		break;
+	case IOMMU_DOMAIN_IDENTITY:
+		return &si_domain->domain;
+	default:
 		return NULL;
 	}
-	domain_update_iommu_cap(dmar_domain);
-
-	domain = &dmar_domain->domain;
-	domain->geometry.aperture_start = 0;
-	domain->geometry.aperture_end   = __DOMAIN_MAX_ADDR(dmar_domain->gaw);
-	domain->geometry.force_aperture = true;
 
-	return domain;
+	return &dmar_domain->domain;
 }
 
 static void intel_iommu_domain_free(struct iommu_domain *domain)
 {
-	domain_exit(to_dmar_domain(domain));
+	struct dmar_domain *dmar_domain = to_dmar_domain(domain);
+
+	if (domain_managed_externally(dmar_domain))
+		domain_exit(dmar_domain);
 }
 
 /*
@@ -5240,13 +5272,33 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
 {
 	int ret;
 
-	if (device_is_rmrr_locked(dev)) {
-		dev_warn(dev, "Device is ineligible for IOMMU domain attach due to platform RMRR requirement.  Contact your platform vendor.\n");
-		return -EPERM;
-	}
+	switch (domain->type) {
+	case IOMMU_DOMAIN_UNMANAGED:
+		if (device_is_rmrr_locked(dev)) {
+			dev_warn(dev, "Device is ineligible for IOMMU domain attach due to platform RMRR requirement. Contact your platform vendor.\n");
+			return -EPERM;
+		}
 
-	if (is_aux_domain(dev, domain))
-		return -EPERM;
+		if (is_aux_domain(dev, domain))
+			return -EPERM;
+
+		break;
+	case IOMMU_DOMAIN_DMA:
+		if (intel_iommu_def_domain_type(dev) == IOMMU_DOMAIN_IDENTITY) {
+			dev_warn(dev, "Device requires identity domain\n");
+			return -EINVAL;
+		}
+		break;
+	case IOMMU_DOMAIN_IDENTITY:
+		if (intel_iommu_def_domain_type(dev) == IOMMU_DOMAIN_DMA) {
+			dev_warn(dev, "Device requires non-identity domain\n");
+			return -EINVAL;
+		}
+		break;
+	default:
+		dev_warn(dev, "Invalid domain type %u\n", domain->type);
+		return -EINVAL;
+	}
 
 	/* normally dev is not mapped */
 	if (unlikely(domain_context_mapped(dev))) {
@@ -5258,7 +5310,7 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
 			dmar_remove_one_dev_info(dev);
 			rcu_read_unlock();
 
-			if (!domain_type_is_vm_or_si(old_domain) &&
+			if (!domain_managed_externally(old_domain) &&
 			    list_empty(&old_domain->devices))
 				domain_exit(old_domain);
 		}
@@ -5307,6 +5359,10 @@ static int intel_iommu_map(struct iommu_domain *domain,
 	int prot = 0;
 	int ret;
 
+	/* Don't bother if hardware passthrough used. */
+	if (dmar_domain == si_domain && hw_pass_through)
+		return 0;
+
 	if (iommu_prot & IOMMU_READ)
 		prot |= DMA_PTE_READ;
 	if (iommu_prot & IOMMU_WRITE)
-- 
2.17.1