Merge tag 'for-linus-xsa-6.1-rc9-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen fixes from Juergen Gross:
 "Two zero-day fixes for the xen-netback driver (XSA-423 and XSA-424)"

* tag 'for-linus-xsa-6.1-rc9-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/netback: don't call kfree_skb() with interrupts disabled
  xen/netback: Ensure protocol headers don't fall in the non-linear area

4 files changed, 133 insertions, 106 deletions

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 1545cbee77a46c..3dbfc8a6924ed3 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -386,7 +386,7 @@ int xenvif_dealloc_kthread(void *data);
 irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data);
 
 bool xenvif_have_rx_work(struct xenvif_queue *queue, bool test_kthread);
-void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb);
+bool xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb);
 
 void xenvif_carrier_on(struct xenvif *vif);
 
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 650fa180220fd6..f3f2c07423a6ac 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -254,14 +254,16 @@ xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
 		skb_clear_hash(skb);
 
-	xenvif_rx_queue_tail(queue, skb);
+	if (!xenvif_rx_queue_tail(queue, skb))
+		goto drop;
+
 	xenvif_kick_thread(queue);
 
 	return NETDEV_TX_OK;
 
  drop:
 	vif->dev->stats.tx_dropped++;
-	dev_kfree_skb(skb);
+	dev_kfree_skb_any(skb);
 	return NETDEV_TX_OK;
 }
 
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 3d2081bbbc8609..054ac0e897f6bb 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -332,10 +332,13 @@ static int xenvif_count_requests(struct xenvif_queue *queue,
 
 
 struct xenvif_tx_cb {
-	u16 pending_idx;
+	u16 copy_pending_idx[XEN_NETBK_LEGACY_SLOTS_MAX + 1];
+	u8 copy_count;
 };
 
 #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
+#define copy_pending_idx(skb, i) (XENVIF_TX_CB(skb)->copy_pending_idx[i])
+#define copy_count(skb) (XENVIF_TX_CB(skb)->copy_count)
 
 static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
 					   u16 pending_idx,
@@ -370,31 +373,93 @@ static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
 	return skb;
 }
 
-static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue,
-							struct sk_buff *skb,
-							struct xen_netif_tx_request *txp,
-							struct gnttab_map_grant_ref *gop,
-							unsigned int frag_overflow,
-							struct sk_buff *nskb)
+static void xenvif_get_requests(struct xenvif_queue *queue,
+				struct sk_buff *skb,
+				struct xen_netif_tx_request *first,
+				struct xen_netif_tx_request *txfrags,
+			        unsigned *copy_ops,
+			        unsigned *map_ops,
+				unsigned int frag_overflow,
+				struct sk_buff *nskb,
+				unsigned int extra_count,
+				unsigned int data_len)
 {
 	struct skb_shared_info *shinfo = skb_shinfo(skb);
 	skb_frag_t *frags = shinfo->frags;
-	u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
-	int start;
+	u16 pending_idx;
 	pending_ring_idx_t index;
 	unsigned int nr_slots;
+	struct gnttab_copy *cop = queue->tx_copy_ops + *copy_ops;
+	struct gnttab_map_grant_ref *gop = queue->tx_map_ops + *map_ops;
+	struct xen_netif_tx_request *txp = first;
+
+	nr_slots = shinfo->nr_frags + 1;
+
+	copy_count(skb) = 0;
+
+	/* Create copy ops for exactly data_len bytes into the skb head. */
+	__skb_put(skb, data_len);
+	while (data_len > 0) {
+		int amount = data_len > txp->size ? txp->size : data_len;
+
+		cop->source.u.ref = txp->gref;
+		cop->source.domid = queue->vif->domid;
+		cop->source.offset = txp->offset;
+
+		cop->dest.domid = DOMID_SELF;
+		cop->dest.offset = (offset_in_page(skb->data +
+						   skb_headlen(skb) -
+						   data_len)) & ~XEN_PAGE_MASK;
+		cop->dest.u.gmfn = virt_to_gfn(skb->data + skb_headlen(skb)
+				               - data_len);
+
+		cop->len = amount;
+		cop->flags = GNTCOPY_source_gref;
 
-	nr_slots = shinfo->nr_frags;
+		index = pending_index(queue->pending_cons);
+		pending_idx = queue->pending_ring[index];
+		callback_param(queue, pending_idx).ctx = NULL;
+		copy_pending_idx(skb, copy_count(skb)) = pending_idx;
+		copy_count(skb)++;
+
+		cop++;
+		data_len -= amount;
 
-	/* Skip first skb fragment if it is on same page as header fragment. */
-	start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
+		if (amount == txp->size) {
+			/* The copy op covered the full tx_request */
+
+			memcpy(&queue->pending_tx_info[pending_idx].req,
+			       txp, sizeof(*txp));
+			queue->pending_tx_info[pending_idx].extra_count =
+				(txp == first) ? extra_count : 0;
+
+			if (txp == first)
+				txp = txfrags;
+			else
+				txp++;
+			queue->pending_cons++;
+			nr_slots--;
+		} else {
+			/* The copy op partially covered the tx_request.
+			 * The remainder will be mapped.
+			 */
+			txp->offset += amount;
+			txp->size -= amount;
+		}
+	}
 
-	for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
-	     shinfo->nr_frags++, txp++, gop++) {
+	for (shinfo->nr_frags = 0; shinfo->nr_frags < nr_slots;
+	     shinfo->nr_frags++, gop++) {
 		index = pending_index(queue->pending_cons++);
 		pending_idx = queue->pending_ring[index];
-		xenvif_tx_create_map_op(queue, pending_idx, txp, 0, gop);
+		xenvif_tx_create_map_op(queue, pending_idx, txp,
+				        txp == first ? extra_count : 0, gop);
 		frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
+
+		if (txp == first)
+			txp = txfrags;
+		else
+			txp++;
 	}
 
 	if (frag_overflow) {
@@ -415,7 +480,8 @@ static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *que
 		skb_shinfo(skb)->frag_list = nskb;
 	}
 
-	return gop;
+	(*copy_ops) = cop - queue->tx_copy_ops;
+	(*map_ops) = gop - queue->tx_map_ops;
 }
 
 static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
@@ -451,7 +517,7 @@ static int xenvif_tx_check_gop(struct xenvif_queue *queue,
 			       struct gnttab_copy **gopp_copy)
 {
 	struct gnttab_map_grant_ref *gop_map = *gopp_map;
-	u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
+	u16 pending_idx;
 	/* This always points to the shinfo of the skb being checked, which
 	 * could be either the first or the one on the frag_list
 	 */
@@ -462,24 +528,37 @@ static int xenvif_tx_check_gop(struct xenvif_queue *queue,
 	struct skb_shared_info *first_shinfo = NULL;
 	int nr_frags = shinfo->nr_frags;
 	const bool sharedslot = nr_frags &&
-				frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
+				frag_get_pending_idx(&shinfo->frags[0]) ==
+				    copy_pending_idx(skb, copy_count(skb) - 1);
 	int i, err;
 
-	/* Check status of header. */
-	err = (*gopp_copy)->status;
-	if (unlikely(err)) {
-		if (net_ratelimit())
-			netdev_dbg(queue->vif->dev,
-				   "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
-				   (*gopp_copy)->status,
-				   pending_idx,
-				   (*gopp_copy)->source.u.ref);
-		/* The first frag might still have this slot mapped */
-		if (!sharedslot)
-			xenvif_idx_release(queue, pending_idx,
-					   XEN_NETIF_RSP_ERROR);
+	for (i = 0; i < copy_count(skb); i++) {
+		int newerr;
+
+		/* Check status of header. */
+		pending_idx = copy_pending_idx(skb, i);
+
+		newerr = (*gopp_copy)->status;
+		if (likely(!newerr)) {
+			/* The first frag might still have this slot mapped */
+			if (i < copy_count(skb) - 1 || !sharedslot)
+				xenvif_idx_release(queue, pending_idx,
+						   XEN_NETIF_RSP_OKAY);
+		} else {
+			err = newerr;
+			if (net_ratelimit())
+				netdev_dbg(queue->vif->dev,
+					   "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
+					   (*gopp_copy)->status,
+					   pending_idx,
+					   (*gopp_copy)->source.u.ref);
+			/* The first frag might still have this slot mapped */
+			if (i < copy_count(skb) - 1 || !sharedslot)
+				xenvif_idx_release(queue, pending_idx,
+						   XEN_NETIF_RSP_ERROR);
+		}
+		(*gopp_copy)++;
 	}
-	(*gopp_copy)++;
 
 check_frags:
 	for (i = 0; i < nr_frags; i++, gop_map++) {
@@ -526,14 +605,6 @@ check_frags:
 		if (err)
 			continue;
 
-		/* First error: if the header haven't shared a slot with the
-		 * first frag, release it as well.
-		 */
-		if (!sharedslot)
-			xenvif_idx_release(queue,
-					   XENVIF_TX_CB(skb)->pending_idx,
-					   XEN_NETIF_RSP_OKAY);
-
 		/* Invalidate preceding fragments of this skb. */
 		for (j = 0; j < i; j++) {
 			pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
@@ -803,7 +874,6 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 				     unsigned *copy_ops,
 				     unsigned *map_ops)
 {
-	struct gnttab_map_grant_ref *gop = queue->tx_map_ops;
 	struct sk_buff *skb, *nskb;
 	int ret;
 	unsigned int frag_overflow;
@@ -885,8 +955,12 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 			continue;
 		}
 
+		data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN) ?
+			XEN_NETBACK_TX_COPY_LEN : txreq.size;
+
 		ret = xenvif_count_requests(queue, &txreq, extra_count,
 					    txfrags, work_to_do);
+
 		if (unlikely(ret < 0))
 			break;
 
@@ -912,9 +986,8 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 		index = pending_index(queue->pending_cons);
 		pending_idx = queue->pending_ring[index];
 
-		data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN &&
-			    ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
-			XEN_NETBACK_TX_COPY_LEN : txreq.size;
+		if (ret >= XEN_NETBK_LEGACY_SLOTS_MAX - 1 && data_len < txreq.size)
+			data_len = txreq.size;
 
 		skb = xenvif_alloc_skb(data_len);
 		if (unlikely(skb == NULL)) {
@@ -925,8 +998,6 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 		}
 
 		skb_shinfo(skb)->nr_frags = ret;
-		if (data_len < txreq.size)
-			skb_shinfo(skb)->nr_frags++;
 		/* At this point shinfo->nr_frags is in fact the number of
 		 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
 		 */
@@ -988,54 +1059,19 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 					     type);
 		}
 
-		XENVIF_TX_CB(skb)->pending_idx = pending_idx;
-
-		__skb_put(skb, data_len);
-		queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
-		queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid;
-		queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
-
-		queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
-			virt_to_gfn(skb->data);
-		queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
-		queue->tx_copy_ops[*copy_ops].dest.offset =
-			offset_in_page(skb->data) & ~XEN_PAGE_MASK;
-
-		queue->tx_copy_ops[*copy_ops].len = data_len;
-		queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
-
-		(*copy_ops)++;
-
-		if (data_len < txreq.size) {
-			frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
-					     pending_idx);
-			xenvif_tx_create_map_op(queue, pending_idx, &txreq,
-						extra_count, gop);
-			gop++;
-		} else {
-			frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
-					     INVALID_PENDING_IDX);
-			memcpy(&queue->pending_tx_info[pending_idx].req,
-			       &txreq, sizeof(txreq));
-			queue->pending_tx_info[pending_idx].extra_count =
-				extra_count;
-		}
-
-		queue->pending_cons++;
-
-		gop = xenvif_get_requests(queue, skb, txfrags, gop,
-				          frag_overflow, nskb);
+		xenvif_get_requests(queue, skb, &txreq, txfrags, copy_ops,
+				    map_ops, frag_overflow, nskb, extra_count,
+				    data_len);
 
 		__skb_queue_tail(&queue->tx_queue, skb);
 
 		queue->tx.req_cons = idx;
 
-		if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) ||
+		if ((*map_ops >= ARRAY_SIZE(queue->tx_map_ops)) ||
 		    (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
 			break;
 	}
 
-	(*map_ops) = gop - queue->tx_map_ops;
 	return;
 }
 
@@ -1114,9 +1150,8 @@ static int xenvif_tx_submit(struct xenvif_queue *queue)
 	while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
 		struct xen_netif_tx_request *txp;
 		u16 pending_idx;
-		unsigned data_len;
 
-		pending_idx = XENVIF_TX_CB(skb)->pending_idx;
+		pending_idx = copy_pending_idx(skb, 0);
 		txp = &queue->pending_tx_info[pending_idx].req;
 
 		/* Check the remap error code. */
@@ -1135,18 +1170,6 @@ static int xenvif_tx_submit(struct xenvif_queue *queue)
 			continue;
 		}
 
-		data_len = skb->len;
-		callback_param(queue, pending_idx).ctx = NULL;
-		if (data_len < txp->size) {
-			/* Append the packet payload as a fragment. */
-			txp->offset += data_len;
-			txp->size -= data_len;
-		} else {
-			/* Schedule a response immediately. */
-			xenvif_idx_release(queue, pending_idx,
-					   XEN_NETIF_RSP_OKAY);
-		}
-
 		if (txp->flags & XEN_NETTXF_csum_blank)
 			skb->ip_summed = CHECKSUM_PARTIAL;
 		else if (txp->flags & XEN_NETTXF_data_validated)
@@ -1332,7 +1355,7 @@ static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
 /* Called after netfront has transmitted */
 int xenvif_tx_action(struct xenvif_queue *queue, int budget)
 {
-	unsigned nr_mops, nr_cops = 0;
+	unsigned nr_mops = 0, nr_cops = 0;
 	int work_done, ret;
 
 	if (unlikely(!tx_work_todo(queue)))
diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c
index 9327621771109a..0ba754ebc5baaf 100644
--- a/drivers/net/xen-netback/rx.c
+++ b/drivers/net/xen-netback/rx.c
@@ -82,9 +82,10 @@ static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue)
 	return false;
 }
 
-void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb)
+bool xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb)
 {
 	unsigned long flags;
+	bool ret = true;
 
 	spin_lock_irqsave(&queue->rx_queue.lock, flags);
 
@@ -92,8 +93,7 @@ void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb)
 		struct net_device *dev = queue->vif->dev;
 
 		netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
-		kfree_skb(skb);
-		queue->vif->dev->stats.rx_dropped++;
+		ret = false;
 	} else {
 		if (skb_queue_empty(&queue->rx_queue))
 			xenvif_update_needed_slots(queue, skb);
@@ -104,6 +104,8 @@ void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb)
 	}
 
 	spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
+
+	return ret;
 }
 
 static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue)