iommu/amd: Add amd_iommu_domain_direct_map function

This function can be used to switch a domain into
paging-mode 0. In this mode all devices can access physical
system memory directly without any remapping.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

Conflicts:

	drivers/iommu/amd_iommu.c

Change-Id: Iea5e664f34bb8fe8e2bb87bdc1cb44ca170a876f

2 files changed, 40 insertions, 3 deletions

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 61214b85e434..e12ea6a38907 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1702,9 +1702,12 @@ static bool dma_ops_domain(struct protection_domain *domain)
 
 static void set_dte_entry(u16 devid, struct protection_domain *domain, bool ats)
 {
-	u64 pte_root = virt_to_phys(domain->pt_root);
+	u64 pte_root = 0;
 	u64 flags = 0;
 
+	if (domain->mode != PAGE_MODE_NONE)
+		pte_root = virt_to_phys(domain->pt_root);
+
 	pte_root |= (domain->mode & DEV_ENTRY_MODE_MASK)
 		    << DEV_ENTRY_MODE_SHIFT;
 	pte_root |= IOMMU_PTE_IR | IOMMU_PTE_IW | IOMMU_PTE_P | IOMMU_PTE_TV;
@@ -2800,7 +2803,8 @@ static void amd_iommu_domain_destroy(struct iommu_domain *dom)
 
 	BUG_ON(domain->dev_cnt != 0);
 
-	free_pagetable(domain);
+	if (domain->mode != PAGE_MODE_NONE)
+		free_pagetable(domain);
 
 	protection_domain_free(domain);
 
@@ -2863,6 +2867,9 @@ static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova,
 	int prot = 0;
 	int ret;
 
+	if (domain->mode == PAGE_MODE_NONE)
+		return -EINVAL;
+
 	if (iommu_prot & IOMMU_READ)
 		prot |= IOMMU_PROT_IR;
 	if (iommu_prot & IOMMU_WRITE)
@@ -2881,6 +2888,9 @@ static size_t amd_iommu_unmap(struct iommu_domain *dom, unsigned long iova,
 	struct protection_domain *domain = dom->priv;
 	size_t unmap_size;
 
+	if (domain->mode == PAGE_MODE_NONE)
+		return -EINVAL;
+
 	mutex_lock(&domain->api_lock);
 	unmap_size = iommu_unmap_page(domain, iova, page_size);
 	mutex_unlock(&domain->api_lock);
@@ -2898,6 +2908,9 @@ static phys_addr_t amd_iommu_iova_to_phys(struct iommu_domain *dom,
 	phys_addr_t paddr;
 	u64 *pte, __pte;
 
+	if (domain->mode == PAGE_MODE_NONE)
+		return iova;
+
 	pte = fetch_pte(domain, iova);
 
 	if (!pte || !IOMMU_PTE_PRESENT(*pte))
@@ -2954,8 +2967,8 @@ static struct iommu_ops amd_iommu_ops = {
 	.unmap = amd_iommu_unmap,
 	.iova_to_phys = amd_iommu_iova_to_phys,
 	.domain_has_cap = amd_iommu_domain_has_cap,
-	.pgsize_bitmap	= AMD_IOMMU_PGSIZES,
 	.device_group = amd_iommu_device_group,
+	.pgsize_bitmap	= AMD_IOMMU_PGSIZES,
 };
 
 /*****************************************************************************
@@ -3013,3 +3026,24 @@ int amd_iommu_unregister_ppr_notifier(struct notifier_block *nb)
 	return atomic_notifier_chain_unregister(&ppr_notifier, nb);
 }
 EXPORT_SYMBOL(amd_iommu_unregister_ppr_notifier);
+
+void amd_iommu_domain_direct_map(struct iommu_domain *dom)
+{
+	struct protection_domain *domain = dom->priv;
+	unsigned long flags;
+
+	spin_lock_irqsave(&domain->lock, flags);
+
+	/* Update data structure */
+	domain->mode    = PAGE_MODE_NONE;
+	domain->updated = true;
+
+	/* Make changes visible to IOMMUs */
+	update_domain(domain);
+
+	/* Page-table is not visible to IOMMU anymore, so free it */
+	free_pagetable(domain);
+
+	spin_unlock_irqrestore(&domain->lock, flags);
+}
+EXPORT_SYMBOL(amd_iommu_domain_direct_map);
diff --git a/drivers/iommu/amd_iommu_proto.h b/drivers/iommu/amd_iommu_proto.h
index cfe2dfc64523..2c4554e963c7 100644
--- a/drivers/iommu/amd_iommu_proto.h
+++ b/drivers/iommu/amd_iommu_proto.h
@@ -33,9 +33,12 @@ extern void amd_iommu_init_notifier(void);
 extern void amd_iommu_init_api(void);
 
 /* IOMMUv2 specific functions */
+struct iommu_domain;
+
 extern bool amd_iommu_v2_supported(void);
 extern int amd_iommu_register_ppr_notifier(struct notifier_block *nb);
 extern int amd_iommu_unregister_ppr_notifier(struct notifier_block *nb);
+extern void amd_iommu_domain_direct_map(struct iommu_domain *dom);
 
 #ifndef CONFIG_AMD_IOMMU_STATS