[PATCH v3 13/18] iommu/vt-d: preserve PASID table of preserved device

[Samiullah Khawaja]

In scalable mode the PASID table is used to fetch the io page tables.
Preserve and restore the PASID table of the preserved devices.

Signed-off-by: Samiullah Khawaja <skhawaja@xxxxxxxxxx>
---
 drivers/iommu/intel/liveupdate.c | 57 ++++++++++++++++++++++++++++++++
 drivers/iommu/intel/pasid.c      |  7 ++--
 drivers/iommu/intel/pasid.h      |  9 +++++
 include/linux/kho/abi/iommu.h    | 13 ++++++++
 4 files changed, 84 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/intel/liveupdate.c b/drivers/iommu/intel/liveupdate.c
index 61d864a2e27c..25c940f12955 100644
--- a/drivers/iommu/intel/liveupdate.c
+++ b/drivers/iommu/intel/liveupdate.c
@@ -14,6 +14,7 @@
 #include <linux/pci.h>
 
 #include "iommu.h"
+#include "pasid.h"
 #include "../iommu-pages.h"
 
 /* 2 tables per bus in scalable mode with upper table at odd bit */
@@ -369,6 +370,7 @@ int intel_iommu_preserve_device(struct device *dev,
 				struct iommu_device_ser *device_ser)
 {
 	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct pasid_table *pasid_table;
 	int ret;
 
 	if (!dev_is_pci(dev)) {
@@ -385,9 +387,49 @@ int intel_iommu_preserve_device(struct device *dev,
 
 	device_ser->domain_iommu_ser.attachment_id = domain_id_iommu(info->domain,
 								     info->iommu);
+
+	if (!sm_supported(info->iommu))
+		return 0;
+
+	pasid_table = intel_pasid_get_table(dev);
+	if (!pasid_table)
+		return -EINVAL;
+
+	ret = pasid_lu_handle_pd(pasid_table->table,
+				 pasid_table->max_pasid,
+				 PASID_LU_OP_PRESERVE);
+	if (ret)
+		return ret;
+
+	device_ser->intel.pasid_table = virt_to_phys(pasid_table->table);
+	device_ser->intel.max_pasid = pasid_table->max_pasid;
 	return 0;
 }
 
+void intel_iommu_unpreserve_device(struct device *dev,
+				   struct iommu_device_ser *device_ser)
+{
+	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct pasid_table *pasid_table;
+
+	if (!dev_is_pci(dev))
+		return;
+
+	if (!info)
+		return;
+
+	if (!sm_supported(info->iommu))
+		return;
+
+	pasid_table = intel_pasid_get_table(dev);
+	if (!pasid_table)
+		return;
+
+	pasid_lu_handle_pd(pasid_table->table,
+			   pasid_table->max_pasid,
+			   PASID_LU_OP_UNPRESERVE);
+}
+
 int intel_iommu_preserve(struct iommu_device *iommu_dev,
 			 struct iommu_hw_ser *ser)
 {
@@ -418,3 +460,18 @@ void intel_iommu_unpreserve(struct iommu_device *iommu_dev,
 	unpreserve_iommu_context_tables(iommu, ser);
 	iommu_unpreserve_pages(iommu->root_entry);
 }
+
+void *intel_pasid_try_restore_table(struct device *dev, u64 max_pasid)
+{
+	struct iommu_device_ser *ser = dev_iommu_restored_state(dev);
+
+	if (!ser || !ser->intel.pasid_table)
+		return NULL;
+
+	BUG_ON(pasid_lu_handle_pd(phys_to_virt(ser->intel.pasid_table),
+				  ser->intel.max_pasid,
+				  PASID_LU_OP_RESTORE));
+	BUG_ON(ser->intel.max_pasid < max_pasid);
+
+	return phys_to_virt(ser->intel.pasid_table);
+}
diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index 89541b74ab8c..5cac8e95f73b 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -60,8 +60,11 @@ int intel_pasid_alloc_table(struct device *dev)
 
 	size = max_pasid >> (PASID_PDE_SHIFT - 3);
 	order = size ? get_order(size) : 0;
-	dir = iommu_alloc_pages_node_sz(info->iommu->node, GFP_KERNEL,
-					1 << (order + PAGE_SHIFT));
+
+	dir = intel_pasid_try_restore_table(dev, 1 << (order + PAGE_SHIFT + 3));
+	if (!dir)
+		dir = iommu_alloc_pages_node_sz(info->iommu->node, GFP_KERNEL,
+						1 << (order + PAGE_SHIFT));
 	if (!dir) {
 		kfree(pasid_table);
 		return -ENOMEM;
diff --git a/drivers/iommu/intel/pasid.h b/drivers/iommu/intel/pasid.h
index 48d3bb6b68de..44e673a4ad8f 100644
--- a/drivers/iommu/intel/pasid.h
+++ b/drivers/iommu/intel/pasid.h
@@ -301,6 +301,15 @@ static inline void pasid_set_eafe(struct pasid_entry *pe)
 
 extern unsigned int intel_pasid_max_id;
 int intel_pasid_alloc_table(struct device *dev);
+#ifdef CONFIG_IOMMU_LIVEUPDATE
+void *intel_pasid_try_restore_table(struct device *dev, u64 max_pasid);
+#else
+static inline void *intel_pasid_try_restore_table(struct device *dev,
+						  u64 max_pasid)
+{
+	return NULL;
+}
+#endif
 void intel_pasid_free_table(struct device *dev);
 struct pasid_table *intel_pasid_get_table(struct device *dev);
 int intel_pasid_setup_first_level(struct intel_iommu *iommu, struct device *dev,
diff --git a/include/linux/kho/abi/iommu.h b/include/linux/kho/abi/iommu.h
index ad760c497e13..27d1fcd7f7e2 100644
--- a/include/linux/kho/abi/iommu.h
+++ b/include/linux/kho/abi/iommu.h
@@ -127,6 +127,16 @@ struct iommu_dev_map_ser {
 	u64 iommu_phys;
 } __packed;
 
+/**
+ * struct iommu_device_intel_ser - Intel specific state of serialized device
+ * @pasid_table: Physical address of pasid table
+ * @max_pasid: Maximum supported pasid
+ */
+struct iommu_device_intel_ser {
+	u64 pasid_table;
+	u64 max_pasid;
+} __packed;
+
 /**
  * struct iommu_device_ser - Serialized state of a device
  * @hdr: Common object header
@@ -139,6 +149,9 @@ struct iommu_device_ser {
 	u32 devid;
 	u32 pci_domain_nr;
 	struct iommu_dev_map_ser domain_iommu_ser;
+	union {
+		struct iommu_device_intel_ser intel;
+	};
 } __packed;
 
 /**
-- 
2.54.0.1136.gdb2ca164c4-goog