net: Disable netmap backend when not supported
This patch fixes configure so that the netmap backend is not compiled in if the
host doesn't support an API version >= 11. A version upper bound (15) has been
added so that the netmap API can be extended with some minor features without
requiring QEMU code modifications.
Moreover, some changes have been done to net/netmap.c in order to reflect the
current netmap API/ABI (11).
The NETMAP_WITH_LIBS macro makes possible to include some utilities (e.g.
netmap ring macros, D(), RD() and other high level functions) through the netmap
headers. In this way we get rid of the D and RD macro definitions in the QEMU
code, and we open the way for further code simplifications that will be
introduced by future patches.
Signed-off-by: Vincenzo Maffione <v.maffione@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/configure b/configure
index 00f9070..9ad3ff3 100755
--- a/configure
+++ b/configure
@@ -2215,13 +2215,21 @@
fi
##########################################
-# netmap headers probe
+# netmap support probe
+# Apart from looking for netmap headers, we make sure that the host API version
+# supports the netmap backend (>=11). The upper bound (15) is meant to simulate
+# a minor/major version number. Minor new features will be marked with values up
+# to 15, and if something happens that requires a change to the backend we will
+# move above 15, submit the backend fixes and modify this two bounds.
if test "$netmap" != "no" ; then
cat > $TMPC << EOF
#include <inttypes.h>
#include <net/if.h>
#include <net/netmap.h>
#include <net/netmap_user.h>
+#if (NETMAP_API < 11) || (NETMAP_API > 15)
+#error
+#endif
int main(void) { return 0; }
EOF
if compile_prog "" "" ; then
diff --git a/net/netmap.c b/net/netmap.c
index 73f6d7a..8213304 100644
--- a/net/netmap.c
+++ b/net/netmap.c
@@ -27,6 +27,8 @@
#include <net/if.h>
#include <sys/mman.h>
#include <stdint.h>
+#include <stdio.h>
+#define NETMAP_WITH_LIBS
#include <net/netmap.h>
#include <net/netmap_user.h>
@@ -58,31 +60,6 @@
int vnet_hdr_len; /* Current virtio-net header length. */
} NetmapState;
-#define D(format, ...) \
- do { \
- struct timeval __xxts; \
- gettimeofday(&__xxts, NULL); \
- printf("%03d.%06d %s [%d] " format "\n", \
- (int)__xxts.tv_sec % 1000, (int)__xxts.tv_usec, \
- __func__, __LINE__, ##__VA_ARGS__); \
- } while (0)
-
-/* Rate limited version of "D", lps indicates how many per second */
-#define RD(lps, format, ...) \
- do { \
- static int t0, __cnt; \
- struct timeval __xxts; \
- gettimeofday(&__xxts, NULL); \
- if (t0 != __xxts.tv_sec) { \
- t0 = __xxts.tv_sec; \
- __cnt = 0; \
- } \
- if (__cnt++ < lps) { \
- D(format, ##__VA_ARGS__); \
- } \
- } while (0)
-
-
#ifndef __FreeBSD__
#define pkt_copy bcopy
#else
@@ -239,7 +216,7 @@
return size;
}
- if (ring->avail == 0) {
+ if (nm_ring_empty(ring)) {
/* No available slots in the netmap TX ring. */
netmap_write_poll(s, true);
return 0;
@@ -252,8 +229,7 @@
ring->slot[i].len = size;
ring->slot[i].flags = 0;
pkt_copy(buf, dst, size);
- ring->cur = NETMAP_RING_NEXT(ring, i);
- ring->avail--;
+ ring->cur = ring->head = nm_ring_next(ring, i);
ioctl(s->me.fd, NIOCTXSYNC, NULL);
return size;
@@ -269,7 +245,6 @@
uint8_t *dst;
int j;
uint32_t i;
- uint32_t avail;
if (unlikely(!ring)) {
/* Drop the packet. */
@@ -277,9 +252,8 @@
}
last = i = ring->cur;
- avail = ring->avail;
- if (avail < iovcnt) {
+ if (nm_ring_space(ring) < iovcnt) {
/* Not enough netmap slots. */
netmap_write_poll(s, true);
return 0;
@@ -295,7 +269,7 @@
while (iov_frag_size) {
nm_frag_size = MIN(iov_frag_size, ring->nr_buf_size);
- if (unlikely(avail == 0)) {
+ if (unlikely(nm_ring_empty(ring))) {
/* We run out of netmap slots while splitting the
iovec fragments. */
netmap_write_poll(s, true);
@@ -310,8 +284,7 @@
pkt_copy(iov[j].iov_base + offset, dst, nm_frag_size);
last = i;
- i = NETMAP_RING_NEXT(ring, i);
- avail--;
+ i = nm_ring_next(ring, i);
offset += nm_frag_size;
iov_frag_size -= nm_frag_size;
@@ -320,9 +293,8 @@
/* The last slot must not have NS_MOREFRAG set. */
ring->slot[last].flags &= ~NS_MOREFRAG;
- /* Now update ring->cur and ring->avail. */
- ring->cur = i;
- ring->avail = avail;
+ /* Now update ring->cur and ring->head. */
+ ring->cur = ring->head = i;
ioctl(s->me.fd, NIOCTXSYNC, NULL);
@@ -345,7 +317,7 @@
/* Keep sending while there are available packets into the netmap
RX ring and the forwarding path towards the peer is open. */
- while (ring->avail > 0 && qemu_can_send_packet(&s->nc)) {
+ while (!nm_ring_empty(ring) && qemu_can_send_packet(&s->nc)) {
uint32_t i;
uint32_t idx;
bool morefrag;
@@ -360,11 +332,10 @@
s->iov[iovcnt].iov_len = ring->slot[i].len;
iovcnt++;
- ring->cur = NETMAP_RING_NEXT(ring, i);
- ring->avail--;
- } while (ring->avail && morefrag);
+ ring->cur = ring->head = nm_ring_next(ring, i);
+ } while (!nm_ring_empty(ring) && morefrag);
- if (unlikely(!ring->avail && morefrag)) {
+ if (unlikely(nm_ring_empty(ring) && morefrag)) {
RD(5, "[netmap_send] ran out of slots, with a pending"
"incomplete packet\n");
}
