Merge branch 'Introduce-XDP-to-ena'

Sameeh Jubran says:

====================
Introduce XDP to ena

This patchset includes 3 patches:
* XDP_DROP implementation
* XDP_TX implementation
* A fix for an issue which might occur due to the XDP_TX patch. I see fit
  to place it as a standalone patch for clarity.

Difference from v2:
* Fixed the usage of rx headroom (XDP_PACKET_HEADROOM)
* Aligned the page_offset of the packet when passing it to the stack
* Switched to using xdp_frame in xdp xmit queue
* Dropped the print for unsupported commands
* Cosmetic changes

Difference from RFC v1 (XDP_DROP patch):
* Initialized xdp.rxq pointer
* Updated max_mtu on attachment of xdp and removed the check from
  ena_change_mtu()
* Moved the xdp execution from ena_rx_skb() to ena_clean_rx_irq()
* Moved xdp buff (struct xdp_buff) from rx_ring to the local stack
* Started using netlink's extack mechanism to deliver error messages to
  the user
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/amazon/ena/ena_ethtool.c

@@ -744,7 +744,9 @@ static int ena_set_channels(struct net_device *netdev,
 	struct ena_adapter *adapter = netdev_priv(netdev);
 	u32 count = channels->combined_count;
 	/* The check for max value is already done in ethtool */
-	if (count < ENA_MIN_NUM_IO_QUEUES)
+	if (count < ENA_MIN_NUM_IO_QUEUES ||
+	    (ena_xdp_present(adapter) &&
+	    !ena_xdp_legal_queue_count(adapter, channels->combined_count)))
 		return -EINVAL;
 
 	return ena_update_queue_count(adapter, count);

drivers/net/ethernet/amazon/ena/ena_netdev.h

@@ -36,6 +36,7 @@
 #include <linux/bitops.h>
 #include <linux/dim.h>
 #include <linux/etherdevice.h>
+#include <linux/if_vlan.h>
 #include <linux/inetdevice.h>
 #include <linux/interrupt.h>
 #include <linux/netdevice.h>
@@ -142,6 +143,18 @@
 
 #define ENA_MMIO_DISABLE_REG_READ	BIT(0)
 
+/* The max MTU size is configured to be the ethernet frame size without
+ * the overhead of the ethernet header, which can have a VLAN header, and
+ * a frame check sequence (FCS).
+ * The buffer size we share with the device is defined to be ENA_PAGE_SIZE
+ */
+
+#define ENA_XDP_MAX_MTU (ENA_PAGE_SIZE - ETH_HLEN - ETH_FCS_LEN - \
+				VLAN_HLEN - XDP_PACKET_HEADROOM)
+
+#define ENA_IS_XDP_INDEX(adapter, index) (((index) >= (adapter)->xdp_first_ring) && \
+	((index) < (adapter)->xdp_first_ring + (adapter)->xdp_num_queues))
+
 struct ena_irq {
 	irq_handler_t handler;
 	void *data;
@@ -155,6 +168,8 @@ struct ena_napi {
 	struct napi_struct napi ____cacheline_aligned;
 	struct ena_ring *tx_ring;
 	struct ena_ring *rx_ring;
+	struct ena_ring *xdp_ring;
+	bool first_interrupt;
 	u32 qid;
 	struct dim dim;
 };
@@ -180,6 +195,17 @@ struct ena_tx_buffer {
 	/* num of buffers used by this skb */
 	u32 num_of_bufs;
 
+	/* XDP buffer structure which is used for sending packets in
+	 * the xdp queues
+	 */
+	struct xdp_frame *xdpf;
+	/* The rx page for the rx buffer that was received in rx and
+	 * re transmitted on xdp tx queues as a result of XDP_TX action.
+	 * We need to free the page once we finished cleaning the buffer in
+	 * clean_xdp_irq()
+	 */
+	struct page *xdp_rx_page;
+
 	/* Indicate if bufs[0] map the linear data of the skb. */
 	u8 map_linear_data;
 
@@ -258,10 +284,13 @@ struct ena_ring {
 	struct ena_adapter *adapter;
 	struct ena_com_io_cq *ena_com_io_cq;
 	struct ena_com_io_sq *ena_com_io_sq;
+	struct bpf_prog *xdp_bpf_prog;
+	struct xdp_rxq_info xdp_rxq;
 
 	u16 next_to_use;
 	u16 next_to_clean;
 	u16 rx_copybreak;
+	u16 rx_headroom;
 	u16 qid;
 	u16 mtu;
 	u16 sgl_size;
@@ -379,6 +408,10 @@ struct ena_adapter {
 	u32 last_monitored_tx_qid;
 
 	enum ena_regs_reset_reason_types reset_reason;
+
+	struct bpf_prog *xdp_bpf_prog;
+	u32 xdp_first_ring;
+	u32 xdp_num_queues;
 };
 
 void ena_set_ethtool_ops(struct net_device *netdev);
@@ -390,8 +423,48 @@ void ena_dump_stats_to_buf(struct ena_adapter *adapter, u8 *buf);
 int ena_update_queue_sizes(struct ena_adapter *adapter,
 			   u32 new_tx_size,
 			   u32 new_rx_size);
+
 int ena_update_queue_count(struct ena_adapter *adapter, u32 new_channel_count);
 
 int ena_get_sset_count(struct net_device *netdev, int sset);
 
+enum ena_xdp_errors_t {
+	ENA_XDP_ALLOWED = 0,
+	ENA_XDP_CURRENT_MTU_TOO_LARGE,
+	ENA_XDP_NO_ENOUGH_QUEUES,
+};
+
+static inline bool ena_xdp_queues_present(struct ena_adapter *adapter)
+{
+	return adapter->xdp_first_ring != 0;
+}
+
+static inline bool ena_xdp_present(struct ena_adapter *adapter)
+{
+	return !!adapter->xdp_bpf_prog;
+}
+
+static inline bool ena_xdp_present_ring(struct ena_ring *ring)
+{
+	return !!ring->xdp_bpf_prog;
+}
+
+static inline int ena_xdp_legal_queue_count(struct ena_adapter *adapter,
+					    u32 queues)
+{
+	return 2 * queues <= adapter->max_num_io_queues;
+}
+
+static inline enum ena_xdp_errors_t ena_xdp_allowed(struct ena_adapter *adapter)
+{
+	enum ena_xdp_errors_t rc = ENA_XDP_ALLOWED;
+
+	if (adapter->netdev->mtu > ENA_XDP_MAX_MTU)
+		rc = ENA_XDP_CURRENT_MTU_TOO_LARGE;
+	else if (!ena_xdp_legal_queue_count(adapter, adapter->num_io_queues))
+		rc = ENA_XDP_NO_ENOUGH_QUEUES;
+
+	return rc;
+}
+
 #endif /* !(ENA_H) */