[PATCH v2 11/16] iommu/vt-d: preserve PASID table of preserved device

[Samiullah Khawaja <skhawaja@google.com>]

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@google.com>
---
 drivers/iommu/intel/iommu.c      |   5 +-
 drivers/iommu/intel/iommu.h      |  12 +++
 drivers/iommu/intel/liveupdate.c | 141 +++++++++++++++++++++++++++++++
 drivers/iommu/intel/pasid.c      |   7 +-
 drivers/iommu/intel/pasid.h      |   9 ++
 include/linux/kho/abi/iommu.h    |  13 +++
 6 files changed, 184 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index b90757164cd8..6d42051dcf7c 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -2951,8 +2951,10 @@ static int clear_unpreserve_context_entry_fn(struct device *dev,
 	if (!info)
 		return 0;
 
-	if (dev_is_pci(dev) && dev_iommu_preserved_state(dev))
+	if (dev_is_pci(dev) && dev_iommu_preserved_state(dev)) {
+		pasid_cleanup_preserved_table(dev);
 		return 0;
+	}
 
 	domain_context_clear(info);
 	return 0;
@@ -4013,6 +4015,7 @@ const struct iommu_ops intel_iommu_ops = {
 	.page_response		= intel_iommu_page_response,
 #ifdef CONFIG_IOMMU_LIVEUPDATE
 	.preserve_device	= intel_iommu_preserve_device,
+	.unpreserve_device	= intel_iommu_unpreserve_device,
 	.preserve		= intel_iommu_preserve,
 	.unpreserve		= intel_iommu_unpreserve,
 #endif
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index 8e37acf7de12..62076a1a0b4d 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -1290,12 +1290,15 @@ static inline int iopf_for_domain_replace(struct iommu_domain *new,
 #ifdef CONFIG_IOMMU_LIVEUPDATE
 int intel_iommu_preserve_device(struct device *dev,
 				struct iommu_device_ser *device_ser);
+void intel_iommu_unpreserve_device(struct device *dev,
+				   struct iommu_device_ser *device_ser);
 int intel_iommu_preserve(struct iommu_device *iommu,
 			 struct iommu_hw_ser *iommu_ser);
 void intel_iommu_unpreserve(struct iommu_device *iommu,
 			    struct iommu_hw_ser *iommu_ser);
 void intel_iommu_liveupdate_restore_root_table(struct intel_iommu *iommu,
 					       struct iommu_hw_ser *iommu_ser);
+void pasid_cleanup_preserved_table(struct device *dev);
 #else
 static inline int intel_iommu_preserve_device(struct device *dev,
 					      struct iommu_device_ser *device_ser)
@@ -1303,6 +1306,11 @@ static inline int intel_iommu_preserve_device(struct device *dev,
 	return -EOPNOTSUPP;
 }
 
+static inline void intel_iommu_unpreserve_device(struct device *dev,
+						 struct iommu_device_ser *device_ser)
+{
+}
+
 static inline int intel_iommu_preserve(struct iommu_device *iommu,
 				       struct iommu_hw_ser *iommu_ser)
 {
@@ -1318,6 +1326,10 @@ static inline void intel_iommu_liveupdate_restore_root_table(struct intel_iommu
 							     struct iommu_hw_ser *iommu_ser)
 {
 }
+
+static inline void pasid_cleanup_preserved_table(struct device *dev)
+{
+}
 #endif
 
 #ifdef CONFIG_INTEL_IOMMU_SVM
diff --git a/drivers/iommu/intel/liveupdate.c b/drivers/iommu/intel/liveupdate.c
index 50a63812533f..404b485e97b9 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"
 
 static void unpreserve_iommu_context_table(struct intel_iommu *iommu, int end)
@@ -140,10 +141,96 @@ void intel_iommu_liveupdate_restore_root_table(struct intel_iommu *iommu,
 	iommu_for_each_preserved_device(_restore_used_domain_ids, iommu);
 }
 
+enum pasid_lu_op {
+	PASID_LU_OP_PRESERVE = 1,
+	PASID_LU_OP_UNPRESERVE,
+	PASID_LU_OP_RESTORE,
+	PASID_LU_OP_FREE,
+};
+
+static int pasid_lu_do_op(void *table, enum pasid_lu_op op)
+{
+	int ret = 0;
+
+	switch (op) {
+	case PASID_LU_OP_PRESERVE:
+		ret = iommu_preserve_page(table);
+		break;
+	case PASID_LU_OP_UNPRESERVE:
+		iommu_unpreserve_page(table);
+		break;
+	case PASID_LU_OP_RESTORE:
+		iommu_restore_page(virt_to_phys(table));
+		break;
+	case PASID_LU_OP_FREE:
+		iommu_free_pages(table);
+		break;
+	}
+
+	return ret;
+}
+
+static int pasid_lu_handle_pd(struct pasid_dir_entry *dir, enum pasid_lu_op op)
+{
+	struct pasid_entry *table;
+	int ret;
+
+	/* Only preserve first table for NO_PASID. */
+	table = get_pasid_table_from_pde(&dir[0]);
+	if (!table)
+		return -EINVAL;
+
+	ret = pasid_lu_do_op(table, op);
+	if (ret)
+		return ret;
+
+	ret = pasid_lu_do_op(dir, op);
+	if (ret)
+		goto err;
+
+	return 0;
+err:
+	if (op == PASID_LU_OP_PRESERVE)
+		pasid_lu_do_op(table, PASID_LU_OP_UNPRESERVE);
+
+	return ret;
+}
+
+void pasid_cleanup_preserved_table(struct device *dev)
+{
+	struct pasid_table *pasid_table;
+	struct pasid_dir_entry *dir;
+	struct pasid_entry *table;
+	size_t dir_size;
+
+	pasid_table = intel_pasid_get_table(dev);
+	if (!pasid_table)
+		return;
+
+	dir = pasid_table->table;
+	table = get_pasid_table_from_pde(&dir[0]);
+	if (!table)
+		return;
+
+	/* Clear everything except the first entry in table. */
+	memset(&table[1], 0, SZ_4K - sizeof(*table));
+
+	/* Use the folio order to calculate the size of Pasid Directory */
+	dir_size = (1 << (folio_order(virt_to_folio(dir)) + PAGE_SHIFT));
+
+	/* Clear everything except the first entry in directory */
+	memset(&dir[1], 0, dir_size - sizeof(struct pasid_dir_entry));
+
+	clflush_cache_range(&table[0], SZ_4K);
+	clflush_cache_range(&dir[0], dir_size);
+}
+
 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)) {
 		dev_err(dev, "Cannot preserve non-PCI device\n");
@@ -155,9 +242,45 @@ 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_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_LU_OP_UNPRESERVE);
+}
+
 int intel_iommu_preserve(struct iommu_device *iommu_dev,
 			 struct iommu_hw_ser *ser)
 {
@@ -194,3 +317,21 @@ void intel_iommu_unpreserve(struct iommu_device *iommu_dev,
 	unpreserve_iommu_context_table(iommu, ROOT_ENTRY_NR);
 	iommu_unpreserve_page(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)
+		return NULL;
+
+	BUG_ON(pasid_lu_handle_pd(phys_to_virt(ser->intel.pasid_table),
+				  PASID_LU_OP_RESTORE));
+	if (WARN_ON_ONCE(ser->intel.max_pasid != max_pasid)) {
+		pasid_lu_handle_pd(phys_to_virt(ser->intel.pasid_table),
+				   PASID_LU_OP_FREE);
+		return NULL;
+	}
+
+	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 5ffedf0dbd5a..5eeb1e0c9bce 100644
--- a/include/linux/kho/abi/iommu.h
+++ b/include/linux/kho/abi/iommu.h
@@ -119,6 +119,16 @@ 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
@@ -131,6 +141,9 @@ 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;
 
 /**
-- 
2.54.0.545.g6539524ca2-goog