i40e: Fix DMA mappings leak

During reallocation of RX buffers, new DMA mappings are created for
those buffers.

steps for reproduction:
while :
do
for ((i=0; i<=8160; i=i+32))
do
ethtool -G enp130s0f0 rx $i tx $i
sleep 0.5
ethtool -g enp130s0f0
done
done

This resulted in crash:
i40e 0000:01:00.1: Unable to allocate memory for the Rx descriptor ring, size=65536
Driver BUG
WARNING: CPU: 0 PID: 4300 at net/core/xdp.c:141 xdp_rxq_info_unreg+0x43/0x50
Call Trace:
i40e_free_rx_resources+0x70/0x80 [i40e]
i40e_set_ringparam+0x27c/0x800 [i40e]
ethnl_set_rings+0x1b2/0x290
genl_family_rcv_msg_doit.isra.15+0x10f/0x150
genl_family_rcv_msg+0xb3/0x160
? rings_fill_reply+0x1a0/0x1a0
genl_rcv_msg+0x47/0x90
? genl_family_rcv_msg+0x160/0x160
netlink_rcv_skb+0x4c/0x120
genl_rcv+0x24/0x40
netlink_unicast+0x196/0x230
netlink_sendmsg+0x204/0x3d0
sock_sendmsg+0x4c/0x50
__sys_sendto+0xee/0x160
? handle_mm_fault+0xbe/0x1e0
? syscall_trace_enter+0x1d3/0x2c0
__x64_sys_sendto+0x24/0x30
do_syscall_64+0x5b/0x1a0
entry_SYSCALL_64_after_hwframe+0x65/0xca
RIP: 0033:0x7f5eac8b035b
Missing register, driver bug
WARNING: CPU: 0 PID: 4300 at net/core/xdp.c:119 xdp_rxq_info_unreg_mem_model+0x69/0x140
Call Trace:
xdp_rxq_info_unreg+0x1e/0x50
i40e_free_rx_resources+0x70/0x80 [i40e]
i40e_set_ringparam+0x27c/0x800 [i40e]
ethnl_set_rings+0x1b2/0x290
genl_family_rcv_msg_doit.isra.15+0x10f/0x150
genl_family_rcv_msg+0xb3/0x160
? rings_fill_reply+0x1a0/0x1a0
genl_rcv_msg+0x47/0x90
? genl_family_rcv_msg+0x160/0x160
netlink_rcv_skb+0x4c/0x120
genl_rcv+0x24/0x40
netlink_unicast+0x196/0x230
netlink_sendmsg+0x204/0x3d0
sock_sendmsg+0x4c/0x50
__sys_sendto+0xee/0x160
? handle_mm_fault+0xbe/0x1e0
? syscall_trace_enter+0x1d3/0x2c0
__x64_sys_sendto+0x24/0x30
do_syscall_64+0x5b/0x1a0
entry_SYSCALL_64_after_hwframe+0x65/0xca
RIP: 0033:0x7f5eac8b035b

This was caused because of new buffers with different RX ring count should
substitute older ones, but those buffers were freed in
i40e_configure_rx_ring and reallocated again with i40e_alloc_rx_bi,
thus kfree on rx_bi caused leak of already mapped DMA.

Fix this by reallocating ZC with rx_bi_zc struct when BPF program loads. Additionally
reallocate back to rx_bi when BPF program unloads.

If BPF program is loaded/unloaded and XSK pools are created, reallocate
RX queues accordingly in XSP_SETUP_XSK_POOL handler.

Fixes: be1222b ("i40e: Separate kernel allocated rx_bi rings from AF_XDP rings")
Signed-off-by: Jan Sokolowski <[email protected]>
Signed-off-by: Mateusz Palczewski <[email protected]>
Signed-off-by: Jacob Keller <[email protected]>
Tested-by: Chandan <[email protected]> (A Contingent Worker at Intel)
Tested-by: Gurucharan <[email protected]> (A Contingent worker at Intel)
Signed-off-by: David S. Miller <[email protected]>

Author: JanJSokolowski

drivers/net/ethernet/intel/i40e/i40e_ethtool.c

@@ -2181,9 +2181,6 @@ static int i40e_set_ringparam(struct net_device *netdev,
 			 */
 			rx_rings[i].tail = hw->hw_addr + I40E_PRTGEN_STATUS;
 			err = i40e_setup_rx_descriptors(&rx_rings[i]);
-			if (err)
-				goto rx_unwind;
-			err = i40e_alloc_rx_bi(&rx_rings[i]);
 			if (err)
 				goto rx_unwind;
 

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -3566,12 +3566,8 @@ static int i40e_configure_rx_ring(struct i40e_ring *ring)
 	if (ring->vsi->type == I40E_VSI_MAIN)
 		xdp_rxq_info_unreg_mem_model(&ring->xdp_rxq);
 
-	kfree(ring->rx_bi);
 	ring->xsk_pool = i40e_xsk_pool(ring);
 	if (ring->xsk_pool) {
-		ret = i40e_alloc_rx_bi_zc(ring);
-		if (ret)
-			return ret;
 		ring->rx_buf_len =
 		  xsk_pool_get_rx_frame_size(ring->xsk_pool);
 		/* For AF_XDP ZC, we disallow packets to span on
@@ -3589,9 +3585,6 @@ static int i40e_configure_rx_ring(struct i40e_ring *ring)
 			 ring->queue_index);
 
 	} else {
-		ret = i40e_alloc_rx_bi(ring);
-		if (ret)
-			return ret;
 		ring->rx_buf_len = vsi->rx_buf_len;
 		if (ring->vsi->type == I40E_VSI_MAIN) {
 			ret = xdp_rxq_info_reg_mem_model(&ring->xdp_rxq,
@@ -13296,6 +13289,14 @@ static int i40e_xdp_setup(struct i40e_vsi *vsi, struct bpf_prog *prog,
 		i40e_reset_and_rebuild(pf, true, true);
 	}
 
+	if (!i40e_enabled_xdp_vsi(vsi) && prog) {
+		if (i40e_realloc_rx_bi_zc(vsi, true))
+			return -ENOMEM;
+	} else if (i40e_enabled_xdp_vsi(vsi) && !prog) {
+		if (i40e_realloc_rx_bi_zc(vsi, false))
+			return -ENOMEM;
+	}
+
 	for (i = 0; i < vsi->num_queue_pairs; i++)
 		WRITE_ONCE(vsi->rx_rings[i]->xdp_prog, vsi->xdp_prog);
 
@@ -13528,6 +13529,7 @@ int i40e_queue_pair_disable(struct i40e_vsi *vsi, int queue_pair)
 
 	i40e_queue_pair_disable_irq(vsi, queue_pair);
 	err = i40e_queue_pair_toggle_rings(vsi, queue_pair, false /* off */);
+	i40e_clean_rx_ring(vsi->rx_rings[queue_pair]);
 	i40e_queue_pair_toggle_napi(vsi, queue_pair, false /* off */);
 	i40e_queue_pair_clean_rings(vsi, queue_pair);
 	i40e_queue_pair_reset_stats(vsi, queue_pair);

drivers/net/ethernet/intel/i40e/i40e_txrx.c

@@ -1457,14 +1457,6 @@ int i40e_setup_tx_descriptors(struct i40e_ring *tx_ring)
 	return -ENOMEM;
 }
 
-int i40e_alloc_rx_bi(struct i40e_ring *rx_ring)
-{
-	unsigned long sz = sizeof(*rx_ring->rx_bi) * rx_ring->count;
-
-	rx_ring->rx_bi = kzalloc(sz, GFP_KERNEL);
-	return rx_ring->rx_bi ? 0 : -ENOMEM;
-}
-
 static void i40e_clear_rx_bi(struct i40e_ring *rx_ring)
 {
 	memset(rx_ring->rx_bi, 0, sizeof(*rx_ring->rx_bi) * rx_ring->count);
@@ -1593,6 +1585,11 @@ int i40e_setup_rx_descriptors(struct i40e_ring *rx_ring)
 
 	rx_ring->xdp_prog = rx_ring->vsi->xdp_prog;
 
+	rx_ring->rx_bi =
+		kcalloc(rx_ring->count, sizeof(*rx_ring->rx_bi), GFP_KERNEL);
+	if (!rx_ring->rx_bi)
+		return -ENOMEM;
+
 	return 0;
 }
 

drivers/net/ethernet/intel/i40e/i40e_txrx.h

@@ -469,7 +469,6 @@ int __i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size);
 bool __i40e_chk_linearize(struct sk_buff *skb);
 int i40e_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frames,
 		  u32 flags);
-int i40e_alloc_rx_bi(struct i40e_ring *rx_ring);
 
 /**
  * i40e_get_head - Retrieve head from head writeback

drivers/net/ethernet/intel/i40e/i40e_xsk.c

@@ -10,14 +10,6 @@
 #include "i40e_txrx_common.h"
 #include "i40e_xsk.h"
 
-int i40e_alloc_rx_bi_zc(struct i40e_ring *rx_ring)
-{
-	unsigned long sz = sizeof(*rx_ring->rx_bi_zc) * rx_ring->count;
-
-	rx_ring->rx_bi_zc = kzalloc(sz, GFP_KERNEL);
-	return rx_ring->rx_bi_zc ? 0 : -ENOMEM;
-}
-
 void i40e_clear_rx_bi_zc(struct i40e_ring *rx_ring)
 {
 	memset(rx_ring->rx_bi_zc, 0,
@@ -29,6 +21,58 @@ static struct xdp_buff **i40e_rx_bi(struct i40e_ring *rx_ring, u32 idx)
 	return &rx_ring->rx_bi_zc[idx];
 }
 
+/**
+ * i40e_realloc_rx_xdp_bi - reallocate SW ring for either XSK or normal buffer
+ * @rx_ring: Current rx ring
+ * @pool_present: is pool for XSK present
+ *
+ * Try allocating memory and return ENOMEM, if failed to allocate.
+ * If allocation was successful, substitute buffer with allocated one.
+ * Returns 0 on success, negative on failure
+ */
+static int i40e_realloc_rx_xdp_bi(struct i40e_ring *rx_ring, bool pool_present)
+{
+	size_t elem_size = pool_present ? sizeof(*rx_ring->rx_bi_zc) :
+					  sizeof(*rx_ring->rx_bi);
+	void *sw_ring = kcalloc(rx_ring->count, elem_size, GFP_KERNEL);
+
+	if (!sw_ring)
+		return -ENOMEM;
+
+	if (pool_present) {
+		kfree(rx_ring->rx_bi);
+		rx_ring->rx_bi = NULL;
+		rx_ring->rx_bi_zc = sw_ring;
+	} else {
+		kfree(rx_ring->rx_bi_zc);
+		rx_ring->rx_bi_zc = NULL;
+		rx_ring->rx_bi = sw_ring;
+	}
+	return 0;
+}
+
+/**
+ * i40e_realloc_rx_bi_zc - reallocate rx SW rings
+ * @vsi: Current VSI
+ * @zc: is zero copy set
+ *
+ * Reallocate buffer for rx_rings that might be used by XSK.
+ * XDP requires more memory, than rx_buf provides.
+ * Returns 0 on success, negative on failure
+ */
+int i40e_realloc_rx_bi_zc(struct i40e_vsi *vsi, bool zc)
+{
+	struct i40e_ring *rx_ring;
+	unsigned long q;
+
+	for_each_set_bit(q, vsi->af_xdp_zc_qps, vsi->alloc_queue_pairs) {
+		rx_ring = vsi->rx_rings[q];
+		if (i40e_realloc_rx_xdp_bi(rx_ring, zc))
+			return -ENOMEM;
+	}
+	return 0;
+}
+
 /**
  * i40e_xsk_pool_enable - Enable/associate an AF_XDP buffer pool to a
  * certain ring/qid
@@ -69,6 +113,10 @@ static int i40e_xsk_pool_enable(struct i40e_vsi *vsi,
 		if (err)
 			return err;
 
+		err = i40e_realloc_rx_xdp_bi(vsi->rx_rings[qid], true);
+		if (err)
+			return err;
+
 		err = i40e_queue_pair_enable(vsi, qid);
 		if (err)
 			return err;
@@ -113,6 +161,9 @@ static int i40e_xsk_pool_disable(struct i40e_vsi *vsi, u16 qid)
 	xsk_pool_dma_unmap(pool, I40E_RX_DMA_ATTR);
 
 	if (if_running) {
+		err = i40e_realloc_rx_xdp_bi(vsi->rx_rings[qid], false);
+		if (err)
+			return err;
 		err = i40e_queue_pair_enable(vsi, qid);
 		if (err)
 			return err;

drivers/net/ethernet/intel/i40e/i40e_xsk.h

@@ -32,7 +32,7 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget);
 
 bool i40e_clean_xdp_tx_irq(struct i40e_vsi *vsi, struct i40e_ring *tx_ring);
 int i40e_xsk_wakeup(struct net_device *dev, u32 queue_id, u32 flags);
-int i40e_alloc_rx_bi_zc(struct i40e_ring *rx_ring);
+int i40e_realloc_rx_bi_zc(struct i40e_vsi *vsi, bool zc);
 void i40e_clear_rx_bi_zc(struct i40e_ring *rx_ring);
 
 #endif /* _I40E_XSK_H_ */