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>
		
			
				
	
	
		
			164 lines
		
	
	
		
			4.0 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			164 lines
		
	
	
		
			4.0 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * QEMU System Emulator
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 *
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 * Copyright (c) 2003-2008 Fabrice Bellard
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 *
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 * Permission is hereby granted, free of charge, to any person obtaining a copy
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 * of this software and associated documentation files (the "Software"), to deal
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 * in the Software without restriction, including without limitation the rights
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 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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 * copies of the Software, and to permit persons to whom the Software is
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 * furnished to do so, subject to the following conditions:
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 *
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 * The above copyright notice and this permission notice shall be included in
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 * all copies or substantial portions of the Software.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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 * THE SOFTWARE.
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 */
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#include "tap_int.h"
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#include "qemu-common.h"
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#include "sysemu/sysemu.h"
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#include "qemu/error-report.h"
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#ifdef __NetBSD__
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#include <sys/ioctl.h>
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#include <net/if.h>
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#include <net/if_tap.h>
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#endif
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int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
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             int vnet_hdr_required, int mq_required)
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{
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    int fd;
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#ifdef TAPGIFNAME
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    struct ifreq ifr;
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#else
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    char *dev;
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    struct stat s;
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#endif
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#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__OpenBSD__)
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    /* if no ifname is given, always start the search from tap0/tun0. */
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    int i;
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    char dname[100];
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    for (i = 0; i < 10; i++) {
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        if (*ifname) {
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            snprintf(dname, sizeof dname, "/dev/%s", ifname);
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        } else {
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#if defined(__OpenBSD__)
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            snprintf(dname, sizeof dname, "/dev/tun%d", i);
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#else
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            snprintf(dname, sizeof dname, "/dev/tap%d", i);
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#endif
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        }
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        TFR(fd = open(dname, O_RDWR));
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        if (fd >= 0) {
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            break;
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        }
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        else if (errno == ENXIO || errno == ENOENT) {
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            break;
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        }
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        if (*ifname) {
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            break;
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        }
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    }
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    if (fd < 0) {
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        error_report("warning: could not open %s (%s): no virtual network emulation",
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                   dname, strerror(errno));
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        return -1;
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    }
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#else
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    TFR(fd = open("/dev/tap", O_RDWR));
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    if (fd < 0) {
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        fprintf(stderr,
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            "warning: could not open /dev/tap: no virtual network emulation: %s\n",
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            strerror(errno));
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        return -1;
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    }
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#endif
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#ifdef TAPGIFNAME
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    if (ioctl(fd, TAPGIFNAME, (void *)&ifr) < 0) {
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        fprintf(stderr, "warning: could not get tap name: %s\n",
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            strerror(errno));
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        return -1;
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    }
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    pstrcpy(ifname, ifname_size, ifr.ifr_name);
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#else
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    if (fstat(fd, &s) < 0) {
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        fprintf(stderr,
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            "warning: could not stat /dev/tap: no virtual network emulation: %s\n",
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            strerror(errno));
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        return -1;
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    }
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    dev = devname(s.st_rdev, S_IFCHR);
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    pstrcpy(ifname, ifname_size, dev);
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#endif
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    if (*vnet_hdr) {
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        /* BSD doesn't have IFF_VNET_HDR */
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        *vnet_hdr = 0;
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        if (vnet_hdr_required && !*vnet_hdr) {
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            error_report("vnet_hdr=1 requested, but no kernel "
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                         "support for IFF_VNET_HDR available");
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            close(fd);
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            return -1;
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        }
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    }
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    fcntl(fd, F_SETFL, O_NONBLOCK);
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    return fd;
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}
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int tap_set_sndbuf(int fd, const NetdevTapOptions *tap)
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{
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    return 0;
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}
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int tap_probe_vnet_hdr(int fd)
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{
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    return 0;
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}
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int tap_probe_has_ufo(int fd)
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{
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    return 0;
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}
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int tap_probe_vnet_hdr_len(int fd, int len)
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{
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    return 0;
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}
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void tap_fd_set_vnet_hdr_len(int fd, int len)
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{
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}
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void tap_fd_set_offload(int fd, int csum, int tso4,
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                        int tso6, int ecn, int ufo)
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{
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}
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int tap_fd_enable(int fd)
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{
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    return -1;
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}
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int tap_fd_disable(int fd)
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{
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    return -1;
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}
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int tap_fd_get_ifname(int fd, char *ifname)
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{
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    return -1;
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}
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