1 files changed, 48 insertions, 25 deletions

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index f51c1e1b3f70..547f12dc4d54 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -1466,6 +1466,16 @@ static void vgic_mmio_write_its_ctlr(struct kvm *kvm, struct vgic_its *its,
 {
 	mutex_lock(&its->cmd_lock);
 
+	/*
+	 * It is UNPREDICTABLE to enable the ITS if any of the CBASER or
+	 * device/collection BASER are invalid
+	 */
+	if (!its->enabled && (val & GITS_CTLR_ENABLE) &&
+		(!(its->baser_device_table & GITS_BASER_VALID) ||
+		 !(its->baser_coll_table & GITS_BASER_VALID) ||
+		 !(its->cbaser & GITS_CBASER_VALID)))
+		goto out;
+
 	its->enabled = !!(val & GITS_CTLR_ENABLE);
 
 	/*
@@ -1474,6 +1484,7 @@ static void vgic_mmio_write_its_ctlr(struct kvm *kvm, struct vgic_its *its,
 	 */
 	vgic_its_process_commands(kvm, its);
 
+out:
 	mutex_unlock(&its->cmd_lock);
 }
 
@@ -1801,37 +1812,33 @@ typedef int (*entry_fn_t)(struct vgic_its *its, u32 id, void *entry,
 static int scan_its_table(struct vgic_its *its, gpa_t base, int size, int esz,
 			  int start_id, entry_fn_t fn, void *opaque)
 {
-	void *entry = kzalloc(esz, GFP_KERNEL);
 	struct kvm *kvm = its->dev->kvm;
 	unsigned long len = size;
 	int id = start_id;
 	gpa_t gpa = base;
+	char entry[esz];
 	int ret;
 
+	memset(entry, 0, esz);
+
 	while (len > 0) {
 		int next_offset;
 		size_t byte_offset;
 
 		ret = kvm_read_guest(kvm, gpa, entry, esz);
 		if (ret)
-			goto out;
+			return ret;
 
 		next_offset = fn(its, id, entry, opaque);
-		if (next_offset <= 0) {
-			ret = next_offset;
-			goto out;
-		}
+		if (next_offset <= 0)
+			return next_offset;
 
 		byte_offset = next_offset * esz;
 		id += next_offset;
 		gpa += byte_offset;
 		len -= byte_offset;
 	}
-	ret =  1;
-
-out:
-	kfree(entry);
-	return ret;
+	return 1;
 }
 
 /**
@@ -1940,6 +1947,14 @@ static int vgic_its_save_itt(struct vgic_its *its, struct its_device *device)
 	return 0;
 }
 
+/**
+ * vgic_its_restore_itt - restore the ITT of a device
+ *
+ * @its: its handle
+ * @dev: device handle
+ *
+ * Return 0 on success, < 0 on error
+ */
 static int vgic_its_restore_itt(struct vgic_its *its, struct its_device *dev)
 {
 	const struct vgic_its_abi *abi = vgic_its_get_abi(its);
@@ -1951,6 +1966,10 @@ static int vgic_its_restore_itt(struct vgic_its *its, struct its_device *dev)
 	ret = scan_its_table(its, base, max_size, ite_esz, 0,
 			     vgic_its_restore_ite, dev);
 
+	/* scan_its_table returns +1 if all ITEs are invalid */
+	if (ret > 0)
+		ret = 0;
+
 	return ret;
 }
 
@@ -2048,11 +2067,12 @@ static int vgic_its_device_cmp(void *priv, struct list_head *a,
 static int vgic_its_save_device_tables(struct vgic_its *its)
 {
 	const struct vgic_its_abi *abi = vgic_its_get_abi(its);
+	u64 baser = its->baser_device_table;
 	struct its_device *dev;
 	int dte_esz = abi->dte_esz;
-	u64 baser;
 
-	baser = its->baser_device_table;
+	if (!(baser & GITS_BASER_VALID))
+		return 0;
 
 	list_sort(NULL, &its->device_list, vgic_its_device_cmp);
 
@@ -2107,10 +2127,7 @@ static int handle_l1_dte(struct vgic_its *its, u32 id, void *addr,
 	ret = scan_its_table(its, gpa, SZ_64K, dte_esz,
 			     l2_start_id, vgic_its_restore_dte, NULL);
 
-	if (ret <= 0)
-		return ret;
-
-	return 1;
+	return ret;
 }
 
 /**
@@ -2140,8 +2157,9 @@ static int vgic_its_restore_device_tables(struct vgic_its *its)
 				     vgic_its_restore_dte, NULL);
 	}
 
+	/* scan_its_table returns +1 if all entries are invalid */
 	if (ret > 0)
-		ret = -EINVAL;
+		ret = 0;
 
 	return ret;
 }
@@ -2198,17 +2216,17 @@ static int vgic_its_restore_cte(struct vgic_its *its, gpa_t gpa, int esz)
 static int vgic_its_save_collection_table(struct vgic_its *its)
 {
 	const struct vgic_its_abi *abi = vgic_its_get_abi(its);
+	u64 baser = its->baser_coll_table;
+	gpa_t gpa = BASER_ADDRESS(baser);
 	struct its_collection *collection;
 	u64 val;
-	gpa_t gpa;
 	size_t max_size, filled = 0;
 	int ret, cte_esz = abi->cte_esz;
 
-	gpa = BASER_ADDRESS(its->baser_coll_table);
-	if (!gpa)
+	if (!(baser & GITS_BASER_VALID))
 		return 0;
 
-	max_size = GITS_BASER_NR_PAGES(its->baser_coll_table) * SZ_64K;
+	max_size = GITS_BASER_NR_PAGES(baser) * SZ_64K;
 
 	list_for_each_entry(collection, &its->collection_list, coll_list) {
 		ret = vgic_its_save_cte(its, collection, gpa, cte_esz);
@@ -2239,17 +2257,18 @@ static int vgic_its_save_collection_table(struct vgic_its *its)
 static int vgic_its_restore_collection_table(struct vgic_its *its)
 {
 	const struct vgic_its_abi *abi = vgic_its_get_abi(its);
+	u64 baser = its->baser_coll_table;
 	int cte_esz = abi->cte_esz;
 	size_t max_size, read = 0;
 	gpa_t gpa;
 	int ret;
 
-	if (!(its->baser_coll_table & GITS_BASER_VALID))
+	if (!(baser & GITS_BASER_VALID))
 		return 0;
 
-	gpa = BASER_ADDRESS(its->baser_coll_table);
+	gpa = BASER_ADDRESS(baser);
 
-	max_size = GITS_BASER_NR_PAGES(its->baser_coll_table) * SZ_64K;
+	max_size = GITS_BASER_NR_PAGES(baser) * SZ_64K;
 
 	while (read < max_size) {
 		ret = vgic_its_restore_cte(its, gpa, cte_esz);
@@ -2258,6 +2277,10 @@ static int vgic_its_restore_collection_table(struct vgic_its *its)
 		gpa += cte_esz;
 		read += cte_esz;
 	}
+
+	if (ret > 0)
+		return 0;
+
 	return ret;
 }