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tap: multiqueue support 

Recently, linux support multiqueue tap which could let userspace call TUNSETIFF
for a signle device many times to create multiple file descriptors as
independent queues. User could also enable/disabe a specific queue through
TUNSETQUEUE.

The patch adds the generic infrastructure to create multiqueue taps. To achieve
this a new parameter "queues" were introduced to specify how many queues were
expected to be created for tap by qemu itself. Alternatively, management could
also pass multiple pre-created tap file descriptors separated with ':' through a
new parameter fds like -netdev tap,id=hn0,fds="X:Y:..:Z". Multiple vhost file
descriptors could also be passed in this way.

Each TAPState were still associated to a tap fd, which mean multiple TAPStates
were created when user needs multiqueue taps. Since each TAPState contains one
NetClientState, with the multiqueue nic support, an N peers of NetClientState
were built up.

A new parameter, mq_required were introduce in tap_open() to create multiqueue
tap fds.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Jason Wang 2013-01-30 19:12:34 +08:00 committed by Anthony Liguori
parent e5dc0b402e
commit 264986e2c8
9 changed files with 139 additions and 44 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/net/tap.h
View File

@ -37,7 +37,6 @@ void tap_set_offload(NetClientState *nc, int csum, int tso4, int tso6, int ecn,
void tap_set_vnet_hdr_len(NetClientState *nc, int len);
int tap_enable(NetClientState *nc);
int tap_disable(NetClientState *nc);
int tap_get_ifname(NetClientState *nc, char *ifname);
int tap_get_fd(NetClientState *nc);

3
net/tap-aix.c
View File

@ -25,7 +25,8 @@
#include "tap_int.h"
#include <stdio.h>
int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required)
int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
int vnet_hdr_required, int mq_required)
{
fprintf(stderr, "no tap on AIX\n");
return -1;

3
net/tap-bsd.c
View File

@ -33,7 +33,8 @@
#include <net/if_tap.h>
#endif
int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required)
int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
int vnet_hdr_required, int mq_required)
{
int fd;
#ifdef TAPGIFNAME

3
net/tap-haiku.c
View File

@ -25,7 +25,8 @@
#include "tap_int.h"
#include <stdio.h>
int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required)
int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
int vnet_hdr_required, int mq_required)
{
fprintf(stderr, "no tap on Haiku\n");
return -1;

4
net/tap-linux.c
View File

@ -36,12 +36,12 @@
#define PATH_NET_TUN "/dev/net/tun"
int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required)
int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
int vnet_hdr_required, int mq_required)
{
struct ifreq ifr;
int fd, ret;
int len = sizeof(struct virtio_net_hdr);
int mq_required = 0;
TFR(fd = open(PATH_NET_TUN, O_RDWR));
if (fd < 0) {

3
net/tap-solaris.c
View File

@ -173,7 +173,8 @@ static int tap_alloc(char *dev, size_t dev_size)
return tap_fd;
}
int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required)
int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
int vnet_hdr_required, int mq_required)
{
char dev[10]="";
int fd;

154
net/tap.c
View File

@ -558,17 +558,10 @@ int net_init_bridge(const NetClientOptions *opts, const char *name,
static int net_tap_init(const NetdevTapOptions *tap, int *vnet_hdr,
const char *setup_script, char *ifname,
size_t ifname_sz)
size_t ifname_sz, int mq_required)
{
int fd, vnet_hdr_required;
if (tap->has_ifname) {
pstrcpy(ifname, ifname_sz, tap->ifname);
} else {
assert(ifname_sz > 0);
ifname[0] = '\0';
}
if (tap->has_vnet_hdr) {
*vnet_hdr = tap->vnet_hdr;
vnet_hdr_required = *vnet_hdr;
@ -577,7 +570,8 @@ static int net_tap_init(const NetdevTapOptions *tap, int *vnet_hdr,
vnet_hdr_required = 0;
}
TFR(fd = tap_open(ifname, ifname_sz, vnet_hdr, vnet_hdr_required));
TFR(fd = tap_open(ifname, ifname_sz, vnet_hdr, vnet_hdr_required,
mq_required));
if (fd < 0) {
return -1;
}
@ -593,6 +587,8 @@ static int net_tap_init(const NetdevTapOptions *tap, int *vnet_hdr,
return fd;
}
#define MAX_TAP_QUEUES 1024
static int net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
const char *model, const char *name,
const char *ifname, const char *script,
@ -611,17 +607,12 @@ static int net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
return -1;
}
if (tap->has_fd) {
if (tap->has_fd || tap->has_fds) {
snprintf(s->nc.info_str, sizeof(s->nc.info_str), "fd=%d", fd);
} else if (tap->has_helper) {
snprintf(s->nc.info_str, sizeof(s->nc.info_str), "helper=%s",
tap->helper);
} else {
const char *downscript;
downscript = tap->has_downscript ? tap->downscript :
DEFAULT_NETWORK_DOWN_SCRIPT;
snprintf(s->nc.info_str, sizeof(s->nc.info_str),
"ifname=%s,script=%s,downscript=%s", ifname, script,
downscript);
@ -652,7 +643,7 @@ static int net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
error_report("vhost-net requested but could not be initialized");
return -1;
}
} else if (tap->has_vhostfd) {
} else if (tap->has_vhostfd || tap->has_vhostfds) {
error_report("vhostfd= is not valid without vhost");
return -1;
}
@ -660,27 +651,54 @@ static int net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
return 0;
}
static int get_fds(char *str, char *fds[], int max)
{
char *ptr = str, *this;
size_t len = strlen(str);
int i = 0;
while (i < max && ptr < str + len) {
this = strchr(ptr, ':');
if (this == NULL) {
fds[i] = g_strdup(ptr);
} else {
fds[i] = g_strndup(ptr, this - ptr);
}
i++;
if (this == NULL) {
break;
} else {
ptr = this + 1;
}
}
return i;
}
int net_init_tap(const NetClientOptions *opts, const char *name,
NetClientState *peer)
{
const NetdevTapOptions *tap;
int fd, vnet_hdr = 0;
const char *model;
int fd, vnet_hdr = 0, i = 0, queues;
/* for the no-fd, no-helper case */
const char *script = NULL; /* suppress wrong "uninit'd use" gcc warning */
const char *downscript = NULL;
const char *vhostfdname;
char ifname[128];
assert(opts->kind == NET_CLIENT_OPTIONS_KIND_TAP);
tap = opts->tap;
queues = tap->has_queues ? tap->queues : 1;
vhostfdname = tap->has_vhostfd ? tap->vhostfd : NULL;
if (tap->has_fd) {
if (tap->has_ifname || tap->has_script || tap->has_downscript ||
tap->has_vnet_hdr || tap->has_helper) {
tap->has_vnet_hdr || tap->has_helper || tap->has_queues ||
tap->has_fds) {
error_report("ifname=, script=, downscript=, vnet_hdr=, "
"and helper= are invalid with fd=");
"helper=, queues=, and fds= are invalid with fd=");
return -1;
}
@ -693,13 +711,61 @@ int net_init_tap(const NetClientOptions *opts, const char *name,
vnet_hdr = tap_probe_vnet_hdr(fd);
model = "tap";
if (net_init_tap_one(tap, peer, "tap", NULL, NULL,
script, downscript,
vhostfdname, vnet_hdr, fd)) {
return -1;
}
} else if (tap->has_fds) {
char *fds[MAX_TAP_QUEUES];
char *vhost_fds[MAX_TAP_QUEUES];
int nfds, nvhosts;
if (tap->has_ifname || tap->has_script || tap->has_downscript ||
tap->has_vnet_hdr || tap->has_helper || tap->has_queues ||
tap->has_fd) {
error_report("ifname=, script=, downscript=, vnet_hdr=, "
"helper=, queues=, and fd= are invalid with fds=");
return -1;
}
nfds = get_fds(tap->fds, fds, MAX_TAP_QUEUES);
if (tap->has_vhostfds) {
nvhosts = get_fds(tap->vhostfds, vhost_fds, MAX_TAP_QUEUES);
if (nfds != nvhosts) {
error_report("The number of fds passed does not match the "
"number of vhostfds passed");
return -1;
}
}
for (i = 0; i < nfds; i++) {
fd = monitor_handle_fd_param(cur_mon, fds[i]);
if (fd == -1) {
return -1;
}
fcntl(fd, F_SETFL, O_NONBLOCK);
if (i == 0) {
vnet_hdr = tap_probe_vnet_hdr(fd);
} else if (vnet_hdr != tap_probe_vnet_hdr(fd)) {
error_report("vnet_hdr not consistent across given tap fds");
return -1;
}
if (net_init_tap_one(tap, peer, "tap", name, ifname,
script, downscript,
tap->has_vhostfds ? vhost_fds[i] : NULL,
vnet_hdr, fd)) {
return -1;
}
}
} else if (tap->has_helper) {
if (tap->has_ifname || tap->has_script || tap->has_downscript ||
tap->has_vnet_hdr) {
tap->has_vnet_hdr || tap->has_queues || tap->has_fds) {
error_report("ifname=, script=, downscript=, and vnet_hdr= "
"are invalid with helper=");
"queues=, and fds= are invalid with helper=");
return -1;
}
@ -709,26 +775,48 @@ int net_init_tap(const NetClientOptions *opts, const char *name,
}
fcntl(fd, F_SETFL, O_NONBLOCK);
vnet_hdr = tap_probe_vnet_hdr(fd);
model = "bridge";
if (net_init_tap_one(tap, peer, "bridge", name, ifname,
script, downscript, vhostfdname,
vnet_hdr, fd)) {
return -1;
}
} else {
script = tap->has_script ? tap->script : DEFAULT_NETWORK_SCRIPT;
downscript = tap->has_downscript ? tap->downscript :
DEFAULT_NETWORK_DOWN_SCRIPT;
fd = net_tap_init(tap, &vnet_hdr, script, ifname, sizeof ifname);
if (tap->has_ifname) {
pstrcpy(ifname, sizeof ifname, tap->ifname);
} else {
ifname[0] = '\0';
}
for (i = 0; i < queues; i++) {
fd = net_tap_init(tap, &vnet_hdr, i >= 1 ? "no" : script,
ifname, sizeof ifname, queues > 1);
if (fd == -1) {
return -1;
}
model = "tap";
if (queues > 1 && i == 0 && !tap->has_ifname) {
if (tap_fd_get_ifname(fd, ifname)) {
error_report("Fail to get ifname");
return -1;
}
}
return net_init_tap_one(tap, peer, model, name, ifname, script,
downscript, tap->has_vhostfd ? tap->vhostfd : NULL,
vnet_hdr, fd);
if (net_init_tap_one(tap, peer, "tap", name, ifname,
i >= 1 ? "no" : script,
i >= 1 ? "no" : downscript,
vhostfdname, vnet_hdr, fd)) {
return -1;
}
}
}
return 0;
}
VHostNetState *tap_get_vhost_net(NetClientState *nc)

3
net/tap_int.h
View File

@ -32,7 +32,8 @@
#define DEFAULT_NETWORK_SCRIPT "/etc/qemu-ifup"
#define DEFAULT_NETWORK_DOWN_SCRIPT "/etc/qemu-ifdown"
int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required);
int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
int vnet_hdr_required, int mq_required);
ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen);

5
qapi-schema.json
View File

@ -2533,6 +2533,7 @@
'data': {
'*ifname': 'str',
'*fd': 'str',
'*fds': 'str',
'*script': 'str',
'*downscript': 'str',
'*helper': 'str',
@ -2540,7 +2541,9 @@
'*vnet_hdr': 'bool',
'*vhost': 'bool',
'*vhostfd': 'str',
'*vhostforce': 'bool' } }
'*vhostfds': 'str',
'*vhostforce': 'bool',
'*queues': 'uint32'} }
##
# @NetdevSocketOptions