[PATCH v3 13/24] powerpc/pseries/lpar: Enable VFIO

@@ -137,14 +137,25 @@ static void tce_freemulti_pSeriesLP(struct iommu_table*, long, long);
 
 static int tce_build_pSeriesLP(struct iommu_table *tbl, long tcenum,
 				long npages, unsigned long uaddr,
+				unsigned long *old_tces,
 				enum dma_data_direction direction,
 				struct dma_attrs *attrs)
 {
 	u64 rc = 0;
 	u64 proto_tce, tce;
 	u64 rpn;
-	int ret = 0;
+	int ret = 0, i = 0;
 	long tcenum_start = tcenum, npages_start = npages;
+	static spinlock_t get_tces_lock;
+	static bool get_tces_lock_initialized;
+
+	if (old_tces) {
+		if (!get_tces_lock_initialized) {
+			spin_lock_init(&get_tces_lock);
+			get_tces_lock_initialized = true;
+		}
+		spin_lock(&get_tces_lock);
+	}
 
 	rpn = __pa(uaddr) >> TCE_SHIFT;
 	proto_tce = TCE_PCI_READ;

@@ -153,6 +164,14 @@ static int tce_build_pSeriesLP(struct iommu_table *tbl, long tcenum,
 
 	while (npages--) {
 		tce = proto_tce | (rpn & TCE_RPN_MASK) << TCE_RPN_SHIFT;
+		if (old_tces) {
+			unsigned long oldtce = 0;
+
+			plpar_tce_get((u64)tbl->it_index, (u64)tcenum << 12,
+					&oldtce);
+			old_tces[i] = be64_to_cpu(oldtce);
+			i++;
+		}
 		rc = plpar_tce_put((u64)tbl->it_index, (u64)tcenum << 12, tce);
 
 		if (unlikely(rc == H_NOT_ENOUGH_RESOURCES)) {

@@ -173,13 +192,18 @@ static int tce_build_pSeriesLP(struct iommu_table *tbl, long tcenum,
 		tcenum++;
 		rpn++;
 	}
+
+	if (old_tces)
+		spin_unlock(&get_tces_lock);
+
 	return ret;
 }
 
 static DEFINE_PER_CPU(__be64 *, tce_page);
 
-static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
+static int tce_xchg_pSeriesLP(struct iommu_table *tbl, long tcenum,
 				     long npages, unsigned long uaddr,
+				     unsigned long *old_tces,
 				     enum dma_data_direction direction,
 				     struct dma_attrs *attrs)
 {

@@ -194,6 +218,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
 
 	if ((npages == 1) || !firmware_has_feature(FW_FEATURE_MULTITCE)) {
 		return tce_build_pSeriesLP(tbl, tcenum, npages, uaddr,
+					   old_tces,
 		                           direction, attrs);
 	}
 

@@ -210,6 +235,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
 		if (!tcep) {
 			local_irq_restore(flags);
 			return tce_build_pSeriesLP(tbl, tcenum, npages, uaddr,
+					    old_tces,
 					    direction, attrs);
 		}
 		__this_cpu_write(tce_page, tcep);

@@ -231,6 +257,10 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
 		for (l = 0; l < limit; l++) {
 			tcep[l] = cpu_to_be64(proto_tce | (rpn & TCE_RPN_MASK) << TCE_RPN_SHIFT);
 			rpn++;
+			if (old_tces)
+				plpar_tce_get((u64)tbl->it_index,
+						(u64)(tcenum + l) << 12,
+						&old_tces[tcenum + l]);
 		}
 
 		rc = plpar_tce_put_indirect((u64)tbl->it_index,

@@ -261,6 +291,15 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
 	return ret;
 }
 
+static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
+				     long npages, unsigned long uaddr,
+				     enum dma_data_direction direction,
+				     struct dma_attrs *attrs)
+{
+	return tce_xchg_pSeriesLP(tbl, tcenum, npages, uaddr, NULL,
+			direction, attrs);
+}
+
 static void tce_free_pSeriesLP(struct iommu_table *tbl, long tcenum, long npages)
 {
 	u64 rc;

@@ -634,6 +673,7 @@ static void pci_dma_bus_setup_pSeries(struct pci_bus *bus)
 
 struct iommu_table_ops iommu_table_lpar_multi_ops = {
 	.set = tce_buildmulti_pSeriesLP,
+	.exchange = tce_xchg_pSeriesLP,
 	.clear = tce_freemulti_pSeriesLP,
 	.get = tce_get_pSeriesLP
 };