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net: Disable netmap backend when not supported

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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>
This commit is contained in:
Vincenzo Maffione 2014-02-20 15:40:43 +01:00 committed by Stefan Hajnoczi
parent f6c65bfb93
commit 0a985b3727
2 changed files with 22 additions and 43 deletions
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10
configure vendored
View File

@ -2215,13 +2215,21 @@ EOF
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

55
net/netmap.c
View File

@ -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 @@ typedef struct NetmapState {
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 @@ static ssize_t netmap_receive(NetClientState *nc,
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 @@ static ssize_t netmap_receive(NetClientState *nc,
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 @@ static ssize_t netmap_receive_iov(NetClientState *nc,
uint8_t *dst;
int j;
uint32_t i;
uint32_t avail;
if (unlikely(!ring)) {
/* Drop the packet. */
@ -277,9 +252,8 @@ static ssize_t netmap_receive_iov(NetClientState *nc,
}
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 @@ static ssize_t netmap_receive_iov(NetClientState *nc,
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 @@ static ssize_t netmap_receive_iov(NetClientState *nc,
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 @@ static ssize_t netmap_receive_iov(NetClientState *nc,
/* 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 @@ static void netmap_send(void *opaque)
/* 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 @@ static void netmap_send(void *opaque)
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");
}