[PATCH v2 5/9] iommu/vt-d: Per domain pasid table interfaces

[Lu Baolu]

This patch adds the interfaces for per domain pasid table
management. Currently we allocate one pasid table for all
devices under the scope of an IOMMU. It's insecure in the
cases where multiple devices under one single IOMMU unit
support PASID feature. With per domain pasid table, we can
achieve finer protection and isolation granularity.

Cc: Ashok Raj <ashok.raj@xxxxxxxxx>
Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
Cc: Liu Yi L <yi.l.liu@xxxxxxxxx>
Suggested-by: Ashok Raj <ashok.raj@xxxxxxxxx>
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Reviewed-by: Liu Yi L <yi.l.liu@xxxxxxxxx>
---
 drivers/iommu/intel-pasid.c | 75 +++++++++++++++++++++++++++++++++++++++++++++
 drivers/iommu/intel-pasid.h |  4 +++
 include/linux/intel-iommu.h |  5 +++
 3 files changed, 84 insertions(+)

diff --git a/drivers/iommu/intel-pasid.c b/drivers/iommu/intel-pasid.c
index 0690f39..b8691a6 100644
--- a/drivers/iommu/intel-pasid.c
+++ b/drivers/iommu/intel-pasid.c
@@ -13,6 +13,7 @@
 #include <linux/intel-iommu.h>
 #include <linux/iommu.h>
 #include <linux/memory.h>
+#include <linux/pci.h>
 #include <linux/spinlock.h>
 
 #include "intel-pasid.h"
@@ -58,3 +59,77 @@ void *intel_pasid_lookup_id(int pasid)
 
 	return p;
 }
+
+/*
+ * Interfaces for per domain pasid table management:
+ */
+int intel_pasid_alloc_table(struct device *dev, size_t entry_size,
+			    size_t entry_count)
+{
+	struct device_domain_info *info;
+	struct dmar_domain *domain;
+	struct page *pages;
+	int order;
+
+	info = dev->archdata.iommu;
+	if (WARN_ON(!info || !dev_is_pci(dev) ||
+		    !info->pasid_supported ||
+		    !info->domain))
+		return -EINVAL;
+
+	domain = info->domain;
+
+	if (entry_count > intel_pasid_max_id)
+		entry_count = intel_pasid_max_id;
+
+	order = get_order(entry_size * entry_count);
+	pages = alloc_pages_node(domain->nid, GFP_KERNEL | __GFP_ZERO, order);
+	if (!pages)
+		return -ENOMEM;
+
+	spin_lock(&pasid_lock);
+	if (domain->pasid_table) {
+		__free_pages(pages, order);
+	} else {
+		domain->pasid_table	= page_address(pages);
+		domain->order		= order;
+		domain->max_pasid	= entry_count;
+	}
+	domain->pasid_users++;
+	spin_unlock(&pasid_lock);
+
+	return 0;
+}
+
+void intel_pasid_free_table(struct device *dev)
+{
+	struct dmar_domain *domain;
+
+	domain = get_valid_domain_for_dev(dev);
+	if (!domain || !dev_is_pci(dev))
+		return;
+
+	spin_lock(&pasid_lock);
+	if (domain->pasid_table) {
+		domain->pasid_users--;
+		if (!domain->pasid_users) {
+			free_pages((unsigned long)domain->pasid_table,
+				   domain->order);
+			domain->pasid_table	= NULL;
+			domain->order		= 0;
+			domain->max_pasid	= 0;
+		}
+	}
+	spin_unlock(&pasid_lock);
+}
+
+void *intel_pasid_get_table(struct device *dev)
+{
+	struct dmar_domain *domain;
+
+	domain = get_valid_domain_for_dev(dev);
+	if (!domain)
+		return NULL;
+
+	return domain->pasid_table;
+}
diff --git a/drivers/iommu/intel-pasid.h b/drivers/iommu/intel-pasid.h
index 0c36af0..a90c60b 100644
--- a/drivers/iommu/intel-pasid.h
+++ b/drivers/iommu/intel-pasid.h
@@ -26,5 +26,9 @@ extern u32 intel_pasid_max_id;
 int intel_pasid_alloc_id(void *ptr, int start, int end, gfp_t gfp);
 void intel_pasid_free_id(int pasid);
 void *intel_pasid_lookup_id(int pasid);
+int intel_pasid_alloc_table(struct device *dev, size_t entry_size,
+			    size_t entry_count);
+void intel_pasid_free_table(struct device *dev);
+void *intel_pasid_get_table(struct device *dev);
 
 #endif /* __INTEL_PASID_H */
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index a4463f0..bee7a3f 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -424,6 +424,11 @@ struct dmar_domain {
 					 */
 	u64		max_addr;	/* maximum mapped address */
 
+	void		*pasid_table;	/* pointer of pasid table */
+	unsigned int	pasid_users;	/* User number of pasid table */
+	int		order;		/* the page order of tables */
+	int		max_pasid;	/* max pasid */
+
 	struct iommu_domain domain;	/*
 					 * generic domain data structure for
 					 * iommu core
-- 
2.7.4