Merge branch 'add-XDP-support-to-xen-netfront'

Denis Kirjanov says:

====================
xen networking: add XDP support to xen-netfront

The first patch adds a new extra type to enable proper synchronization
between an RX request/response pair.
The second patch implements BFP interface for xen-netfront.
The third patch enables extra space for XDP processing.

v14:
- fixed compilation warnings

v13:
- fixed compilation due to previous rename

v12:
- xen-netback: rename netfront_xdp_headroom to xdp_headroom

v11:
- add the new headroom constant to netif.h
- xenbus_scanf check
- lock a bulk of puckets in xennet_xdp_xmit()

v10:
- add a new xen_netif_extra_info type to enable proper synchronization
 between an RX request/response pair.
- order local variable declarations

v9:
- assign an xdp program before switching to Reconfiguring
- minor cleanups
- address checkpatch issues

v8:
- add PAGE_POOL config dependency
- keep the state of XDP processing in netfront_xdp_enabled
- fixed allocator type in xdp_rxq_info_reg_mem_model()
- minor cleanups in xen-netback

v7:
- use page_pool_dev_alloc_pages() on page allocation
- remove the leftover break statement from netback_changed

v6:
- added the missing SOB line
- fixed subject

v5:
- split netfront/netback changes
- added a sync point between backend/frontend on switching to XDP
- added pagepool API

v4:
- added verbose patch descriprion
- don't expose the XDP headroom offset to the domU guest
- add a modparam to netback to toggle XDP offset
- don't process jumbo frames for now

v3:
- added XDP_TX support (tested with xdping echoserver)
- added XDP_REDIRECT support (tested with modified xdp_redirect_kern)
- moved xdp negotiation to xen-netback

v2:
- avoid data copying while passing to XDP
- tell xen-netback that we need the headroom space
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 1 deletions

diff --git a/include/xen/interface/io/netif.h b/include/xen/interface/io/netif.h
index 4f20dbc42910..2194322c3c7f 100644
--- a/include/xen/interface/io/netif.h
+++ b/include/xen/interface/io/netif.h
@@ -161,6 +161,19 @@
  */
 
 /*
+ * "xdp-headroom" is used to request that extra space is added
+ * for XDP processing.  The value is measured in bytes and passed by
+ * the frontend to be consistent between both ends.
+ * If the value is greater than zero that means that
+ * an RX response is going to be passed to an XDP program for processing.
+ * XEN_NETIF_MAX_XDP_HEADROOM defines the maximum headroom offset in bytes
+ *
+ * "feature-xdp-headroom" is set to "1" by the netback side like other features
+ * so a guest can check if an XDP program can be processed.
+ */
+#define XEN_NETIF_MAX_XDP_HEADROOM 0x7FFF
+
+/*
  * Control ring
  * ============
  *
@@ -846,7 +859,8 @@ struct xen_netif_tx_request {
 #define XEN_NETIF_EXTRA_TYPE_MCAST_ADD (2)	/* u.mcast */
 #define XEN_NETIF_EXTRA_TYPE_MCAST_DEL (3)	/* u.mcast */
 #define XEN_NETIF_EXTRA_TYPE_HASH      (4)	/* u.hash */
-#define XEN_NETIF_EXTRA_TYPE_MAX       (5)
+#define XEN_NETIF_EXTRA_TYPE_XDP       (5)	/* u.xdp */
+#define XEN_NETIF_EXTRA_TYPE_MAX       (6)
 
 /* xen_netif_extra_info_t flags. */
 #define _XEN_NETIF_EXTRA_FLAG_MORE (0)
@@ -879,6 +893,10 @@ struct xen_netif_extra_info {
 			uint8_t algorithm;
 			uint8_t value[4];
 		} hash;
+		struct {
+			uint16_t headroom;
+			uint16_t pad[2];
+		} xdp;
 		uint16_t pad[3];
 	} u;
 };