iommu/vt-d: Per PCI device pasid table interfaces

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

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Liu Yi L <yi.l.liu@intel.com>
Suggested-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 179 insertions, 0 deletions

diff --git a/drivers/iommu/intel-pasid.c b/drivers/iommu/intel-pasid.c
index e918fe01ce7f..fe95c9bd4d33 100644
--- a/drivers/iommu/intel-pasid.c
+++ b/drivers/iommu/intel-pasid.c
@@ -13,6 +13,8 @@
 #include <linux/intel-iommu.h>
 #include <linux/iommu.h>
 #include <linux/memory.h>
+#include <linux/pci.h>
+#include <linux/pci-ats.h>
 #include <linux/spinlock.h>
 
 #include "intel-pasid.h"
@@ -58,3 +60,180 @@ void *intel_pasid_lookup_id(int pasid)
 
 	return p;
 }
+
+/*
+ * Per device pasid table management:
+ */
+static inline void
+device_attach_pasid_table(struct device_domain_info *info,
+			  struct pasid_table *pasid_table)
+{
+	info->pasid_table = pasid_table;
+	list_add(&info->table, &pasid_table->dev);
+}
+
+static inline void
+device_detach_pasid_table(struct device_domain_info *info,
+			  struct pasid_table *pasid_table)
+{
+	info->pasid_table = NULL;
+	list_del(&info->table);
+}
+
+struct pasid_table_opaque {
+	struct pasid_table	**pasid_table;
+	int			segment;
+	int			bus;
+	int			devfn;
+};
+
+static int search_pasid_table(struct device_domain_info *info, void *opaque)
+{
+	struct pasid_table_opaque *data = opaque;
+
+	if (info->iommu->segment == data->segment &&
+	    info->bus == data->bus &&
+	    info->devfn == data->devfn &&
+	    info->pasid_table) {
+		*data->pasid_table = info->pasid_table;
+		return 1;
+	}
+
+	return 0;
+}
+
+static int get_alias_pasid_table(struct pci_dev *pdev, u16 alias, void *opaque)
+{
+	struct pasid_table_opaque *data = opaque;
+
+	data->segment = pci_domain_nr(pdev->bus);
+	data->bus = PCI_BUS_NUM(alias);
+	data->devfn = alias & 0xff;
+
+	return for_each_device_domain(&search_pasid_table, data);
+}
+
+/*
+ * Allocate a pasid table for @dev. It should be called in a
+ * single-thread context.
+ */
+int intel_pasid_alloc_table(struct device *dev)
+{
+	struct device_domain_info *info;
+	struct pasid_table *pasid_table;
+	struct pasid_table_opaque data;
+	struct page *pages;
+	size_t size, count;
+	int ret, order;
+
+	info = dev->archdata.iommu;
+	if (WARN_ON(!info || !dev_is_pci(dev) ||
+		    !info->pasid_supported || info->pasid_table))
+		return -EINVAL;
+
+	/* DMA alias device already has a pasid table, use it: */
+	data.pasid_table = &pasid_table;
+	ret = pci_for_each_dma_alias(to_pci_dev(dev),
+				     &get_alias_pasid_table, &data);
+	if (ret)
+		goto attach_out;
+
+	pasid_table = kzalloc(sizeof(*pasid_table), GFP_ATOMIC);
+	if (!pasid_table)
+		return -ENOMEM;
+	INIT_LIST_HEAD(&pasid_table->dev);
+
+	size = sizeof(struct pasid_entry);
+	count = min_t(int, pci_max_pasids(to_pci_dev(dev)), intel_pasid_max_id);
+	order = get_order(size * count);
+	pages = alloc_pages_node(info->iommu->node,
+				 GFP_ATOMIC | __GFP_ZERO,
+				 order);
+	if (!pages)
+		return -ENOMEM;
+
+	pasid_table->table = page_address(pages);
+	pasid_table->order = order;
+	pasid_table->max_pasid = count;
+
+attach_out:
+	device_attach_pasid_table(info, pasid_table);
+
+	return 0;
+}
+
+void intel_pasid_free_table(struct device *dev)
+{
+	struct device_domain_info *info;
+	struct pasid_table *pasid_table;
+
+	info = dev->archdata.iommu;
+	if (!info || !dev_is_pci(dev) ||
+	    !info->pasid_supported || !info->pasid_table)
+		return;
+
+	pasid_table = info->pasid_table;
+	device_detach_pasid_table(info, pasid_table);
+
+	if (!list_empty(&pasid_table->dev))
+		return;
+
+	free_pages((unsigned long)pasid_table->table, pasid_table->order);
+	kfree(pasid_table);
+}
+
+struct pasid_table *intel_pasid_get_table(struct device *dev)
+{
+	struct device_domain_info *info;
+
+	info = dev->archdata.iommu;
+	if (!info)
+		return NULL;
+
+	return info->pasid_table;
+}
+
+int intel_pasid_get_dev_max_id(struct device *dev)
+{
+	struct device_domain_info *info;
+
+	info = dev->archdata.iommu;
+	if (!info || !info->pasid_table)
+		return 0;
+
+	return info->pasid_table->max_pasid;
+}
+
+struct pasid_entry *intel_pasid_get_entry(struct device *dev, int pasid)
+{
+	struct pasid_table *pasid_table;
+	struct pasid_entry *entries;
+
+	pasid_table = intel_pasid_get_table(dev);
+	if (WARN_ON(!pasid_table || pasid < 0 ||
+		    pasid >= intel_pasid_get_dev_max_id(dev)))
+		return NULL;
+
+	entries = pasid_table->table;
+
+	return &entries[pasid];
+}
+
+/*
+ * Interfaces for PASID table entry manipulation:
+ */
+static inline void pasid_clear_entry(struct pasid_entry *pe)
+{
+	WRITE_ONCE(pe->val, 0);
+}
+
+void intel_pasid_clear_entry(struct device *dev, int pasid)
+{
+	struct pasid_entry *pe;
+
+	pe = intel_pasid_get_entry(dev, pasid);
+	if (WARN_ON(!pe))
+		return;
+
+	pasid_clear_entry(pe);
+}