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qemu/hw/virtio-net.c
Alex Williamson a697a334b3 virtio-net: Introduce a new bottom half packet TX 
Based on a patch from Mark McLoughlin, this patch introduces a new
bottom half packet transmitter that avoids the latency imposed by
the tx_timer approach.  Rather than scheduling a timer when a TX
packet comes in, schedule a bottom half to be run from the iothread.
The bottom half handler first attempts to flush the queue with
notification disabled (this is where we could race with a guest
without txburst).  If we flush a full burst, reschedule immediately.
If we send short of a full burst, try to re-enable notification.
To avoid a race with TXs that may have occurred, we must then
flush again.  If we find some packets to send, the guest it probably
active, so we can reschedule again.

tx_timer and tx_bh are mutually exclusive, so we can re-use the
tx_waiting flag to indicate one or the other needs to be setup.
This allows us to seamlessly migrate between timer and bh TX
handling.

The bottom half handler becomes the new default and we add a new
tx= option to virtio-net-pci.  Usage:

-device virtio-net-pci,tx=timer # select timer mitigation vs "bh"

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2010-09-07 20:29:29 +03:00

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/*
* Virtio Network Device
*
* Copyright IBM, Corp. 2007
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#include "iov.h"
#include "virtio.h"
#include "net.h"
#include "net/checksum.h"
#include "net/tap.h"
#include "qemu-error.h"
#include "qemu-timer.h"
#include "virtio-net.h"
#include "vhost_net.h"
#define VIRTIO_NET_VM_VERSION 11
#define MAC_TABLE_ENTRIES 64
#define MAX_VLAN (1 << 12) /* Per 802.1Q definition */
typedef struct VirtIONet
{
VirtIODevice vdev;
uint8_t mac[ETH_ALEN];
uint16_t status;
VirtQueue *rx_vq;
VirtQueue *tx_vq;
VirtQueue *ctrl_vq;
NICState *nic;
QEMUTimer *tx_timer;
QEMUBH *tx_bh;
uint32_t tx_timeout;
int32_t tx_burst;
int tx_waiting;
uint32_t has_vnet_hdr;
uint8_t has_ufo;
struct {
VirtQueueElement elem;
ssize_t len;
} async_tx;
int mergeable_rx_bufs;
uint8_t promisc;
uint8_t allmulti;
uint8_t alluni;
uint8_t nomulti;
uint8_t nouni;
uint8_t nobcast;
uint8_t vhost_started;
VMChangeStateEntry *vmstate;
struct {
int in_use;
int first_multi;
uint8_t multi_overflow;
uint8_t uni_overflow;
uint8_t *macs;
} mac_table;
uint32_t *vlans;
DeviceState *qdev;
} VirtIONet;
/* TODO
* - we could suppress RX interrupt if we were so inclined.
*/
static VirtIONet *to_virtio_net(VirtIODevice *vdev)
{
return (VirtIONet *)vdev;
}
static void virtio_net_get_config(VirtIODevice *vdev, uint8_t *config)
{
VirtIONet *n = to_virtio_net(vdev);
struct virtio_net_config netcfg;
netcfg.status = n->status;
memcpy(netcfg.mac, n->mac, ETH_ALEN);
memcpy(config, &netcfg, sizeof(netcfg));
}
static void virtio_net_set_config(VirtIODevice *vdev, const uint8_t *config)
{
VirtIONet *n = to_virtio_net(vdev);
struct virtio_net_config netcfg;
memcpy(&netcfg, config, sizeof(netcfg));
if (memcmp(netcfg.mac, n->mac, ETH_ALEN)) {
memcpy(n->mac, netcfg.mac, ETH_ALEN);
qemu_format_nic_info_str(&n->nic->nc, n->mac);
}
}
static void virtio_net_set_link_status(VLANClientState *nc)
{
VirtIONet *n = DO_UPCAST(NICState, nc, nc)->opaque;
uint16_t old_status = n->status;
if (nc->link_down)
n->status &= ~VIRTIO_NET_S_LINK_UP;
else
n->status |= VIRTIO_NET_S_LINK_UP;
if (n->status != old_status)
virtio_notify_config(&n->vdev);
}
static void virtio_net_reset(VirtIODevice *vdev)
{
VirtIONet *n = to_virtio_net(vdev);
/* Reset back to compatibility mode */
n->promisc = 1;
n->allmulti = 0;
n->alluni = 0;
n->nomulti = 0;
n->nouni = 0;
n->nobcast = 0;
if (n->vhost_started) {
vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), vdev);
n->vhost_started = 0;
}
/* Flush any MAC and VLAN filter table state */
n->mac_table.in_use = 0;
n->mac_table.first_multi = 0;
n->mac_table.multi_overflow = 0;
n->mac_table.uni_overflow = 0;
memset(n->mac_table.macs, 0, MAC_TABLE_ENTRIES * ETH_ALEN);
memset(n->vlans, 0, MAX_VLAN >> 3);
}
static int peer_has_vnet_hdr(VirtIONet *n)
{
if (!n->nic->nc.peer)
return 0;
if (n->nic->nc.peer->info->type != NET_CLIENT_TYPE_TAP)
return 0;
n->has_vnet_hdr = tap_has_vnet_hdr(n->nic->nc.peer);
return n->has_vnet_hdr;
}
static int peer_has_ufo(VirtIONet *n)
{
if (!peer_has_vnet_hdr(n))
return 0;
n->has_ufo = tap_has_ufo(n->nic->nc.peer);
return n->has_ufo;
}
static uint32_t virtio_net_get_features(VirtIODevice *vdev, uint32_t features)
{
VirtIONet *n = to_virtio_net(vdev);
features |= (1 << VIRTIO_NET_F_MAC);
if (peer_has_vnet_hdr(n)) {
tap_using_vnet_hdr(n->nic->nc.peer, 1);
} else {
features &= ~(0x1 << VIRTIO_NET_F_CSUM);
features &= ~(0x1 << VIRTIO_NET_F_HOST_TSO4);
features &= ~(0x1 << VIRTIO_NET_F_HOST_TSO6);
features &= ~(0x1 << VIRTIO_NET_F_HOST_ECN);
features &= ~(0x1 << VIRTIO_NET_F_GUEST_CSUM);
features &= ~(0x1 << VIRTIO_NET_F_GUEST_TSO4);
features &= ~(0x1 << VIRTIO_NET_F_GUEST_TSO6);
features &= ~(0x1 << VIRTIO_NET_F_GUEST_ECN);
}
if (!peer_has_vnet_hdr(n) || !peer_has_ufo(n)) {
features &= ~(0x1 << VIRTIO_NET_F_GUEST_UFO);
features &= ~(0x1 << VIRTIO_NET_F_HOST_UFO);
}
if (!n->nic->nc.peer ||
n->nic->nc.peer->info->type != NET_CLIENT_TYPE_TAP) {
return features;
}
if (!tap_get_vhost_net(n->nic->nc.peer)) {
return features;
}
return vhost_net_get_features(tap_get_vhost_net(n->nic->nc.peer), features);
}
static uint32_t virtio_net_bad_features(VirtIODevice *vdev)
{
uint32_t features = 0;
/* Linux kernel 2.6.25. It understood MAC (as everyone must),
* but also these: */
features |= (1 << VIRTIO_NET_F_MAC);
features |= (1 << VIRTIO_NET_F_CSUM);
features |= (1 << VIRTIO_NET_F_HOST_TSO4);
features |= (1 << VIRTIO_NET_F_HOST_TSO6);
features |= (1 << VIRTIO_NET_F_HOST_ECN);
return features;
}
static void virtio_net_set_features(VirtIODevice *vdev, uint32_t features)
{
VirtIONet *n = to_virtio_net(vdev);
n->mergeable_rx_bufs = !!(features & (1 << VIRTIO_NET_F_MRG_RXBUF));
if (n->has_vnet_hdr) {
tap_set_offload(n->nic->nc.peer,
(features >> VIRTIO_NET_F_GUEST_CSUM) & 1,
(features >> VIRTIO_NET_F_GUEST_TSO4) & 1,
(features >> VIRTIO_NET_F_GUEST_TSO6) & 1,
(features >> VIRTIO_NET_F_GUEST_ECN) & 1,
(features >> VIRTIO_NET_F_GUEST_UFO) & 1);
}
if (!n->nic->nc.peer ||
n->nic->nc.peer->info->type != NET_CLIENT_TYPE_TAP) {
return;
}
if (!tap_get_vhost_net(n->nic->nc.peer)) {
return;
}
vhost_net_ack_features(tap_get_vhost_net(n->nic->nc.peer), features);
}
static int virtio_net_handle_rx_mode(VirtIONet *n, uint8_t cmd,
VirtQueueElement *elem)
{
uint8_t on;
if (elem->out_num != 2 || elem->out_sg[1].iov_len != sizeof(on)) {
fprintf(stderr, "virtio-net ctrl invalid rx mode command\n");
exit(1);
}
on = ldub_p(elem->out_sg[1].iov_base);
if (cmd == VIRTIO_NET_CTRL_RX_MODE_PROMISC)
n->promisc = on;
else if (cmd == VIRTIO_NET_CTRL_RX_MODE_ALLMULTI)
n->allmulti = on;
else if (cmd == VIRTIO_NET_CTRL_RX_MODE_ALLUNI)
n->alluni = on;
else if (cmd == VIRTIO_NET_CTRL_RX_MODE_NOMULTI)
n->nomulti = on;
else if (cmd == VIRTIO_NET_CTRL_RX_MODE_NOUNI)
n->nouni = on;
else if (cmd == VIRTIO_NET_CTRL_RX_MODE_NOBCAST)
n->nobcast = on;
else
return VIRTIO_NET_ERR;
return VIRTIO_NET_OK;
}
static int virtio_net_handle_mac(VirtIONet *n, uint8_t cmd,
VirtQueueElement *elem)
{
struct virtio_net_ctrl_mac mac_data;
if (cmd != VIRTIO_NET_CTRL_MAC_TABLE_SET || elem->out_num != 3 ||
elem->out_sg[1].iov_len < sizeof(mac_data) ||
elem->out_sg[2].iov_len < sizeof(mac_data))
return VIRTIO_NET_ERR;
n->mac_table.in_use = 0;
n->mac_table.first_multi = 0;
n->mac_table.uni_overflow = 0;
n->mac_table.multi_overflow = 0;
memset(n->mac_table.macs, 0, MAC_TABLE_ENTRIES * ETH_ALEN);
mac_data.entries = ldl_le_p(elem->out_sg[1].iov_base);
if (sizeof(mac_data.entries) +
(mac_data.entries * ETH_ALEN) > elem->out_sg[1].iov_len)
return VIRTIO_NET_ERR;
if (mac_data.entries <= MAC_TABLE_ENTRIES) {
memcpy(n->mac_table.macs, elem->out_sg[1].iov_base + sizeof(mac_data),
mac_data.entries * ETH_ALEN);
n->mac_table.in_use += mac_data.entries;
} else {
n->mac_table.uni_overflow = 1;
}
n->mac_table.first_multi = n->mac_table.in_use;
mac_data.entries = ldl_le_p(elem->out_sg[2].iov_base);
if (sizeof(mac_data.entries) +
(mac_data.entries * ETH_ALEN) > elem->out_sg[2].iov_len)
return VIRTIO_NET_ERR;
if (mac_data.entries) {
if (n->mac_table.in_use + mac_data.entries <= MAC_TABLE_ENTRIES) {
memcpy(n->mac_table.macs + (n->mac_table.in_use * ETH_ALEN),
elem->out_sg[2].iov_base + sizeof(mac_data),
mac_data.entries * ETH_ALEN);
n->mac_table.in_use += mac_data.entries;
} else {
n->mac_table.multi_overflow = 1;
}
}
return VIRTIO_NET_OK;
}
static int virtio_net_handle_vlan_table(VirtIONet *n, uint8_t cmd,
VirtQueueElement *elem)
{
uint16_t vid;
if (elem->out_num != 2 || elem->out_sg[1].iov_len != sizeof(vid)) {
fprintf(stderr, "virtio-net ctrl invalid vlan command\n");
return VIRTIO_NET_ERR;
}
vid = lduw_le_p(elem->out_sg[1].iov_base);
if (vid >= MAX_VLAN)
return VIRTIO_NET_ERR;
if (cmd == VIRTIO_NET_CTRL_VLAN_ADD)
n->vlans[vid >> 5] |= (1U << (vid & 0x1f));
else if (cmd == VIRTIO_NET_CTRL_VLAN_DEL)
n->vlans[vid >> 5] &= ~(1U << (vid & 0x1f));
else
return VIRTIO_NET_ERR;
return VIRTIO_NET_OK;
}
static void virtio_net_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIONet *n = to_virtio_net(vdev);
struct virtio_net_ctrl_hdr ctrl;
virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
VirtQueueElement elem;
while (virtqueue_pop(vq, &elem)) {
if ((elem.in_num < 1) || (elem.out_num < 1)) {
fprintf(stderr, "virtio-net ctrl missing headers\n");
exit(1);
}
if (elem.out_sg[0].iov_len < sizeof(ctrl) ||
elem.in_sg[elem.in_num - 1].iov_len < sizeof(status)) {
fprintf(stderr, "virtio-net ctrl header not in correct element\n");
exit(1);
}
ctrl.class = ldub_p(elem.out_sg[0].iov_base);
ctrl.cmd = ldub_p(elem.out_sg[0].iov_base + sizeof(ctrl.class));
if (ctrl.class == VIRTIO_NET_CTRL_RX_MODE)
status = virtio_net_handle_rx_mode(n, ctrl.cmd, &elem);
else if (ctrl.class == VIRTIO_NET_CTRL_MAC)
status = virtio_net_handle_mac(n, ctrl.cmd, &elem);
else if (ctrl.class == VIRTIO_NET_CTRL_VLAN)
status = virtio_net_handle_vlan_table(n, ctrl.cmd, &elem);
stb_p(elem.in_sg[elem.in_num - 1].iov_base, status);
virtqueue_push(vq, &elem, sizeof(status));
virtio_notify(vdev, vq);
}
}
/* RX */
static void virtio_net_handle_rx(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIONet *n = to_virtio_net(vdev);
qemu_flush_queued_packets(&n->nic->nc);
/* We now have RX buffers, signal to the IO thread to break out of the
* select to re-poll the tap file descriptor */
qemu_notify_event();
}
static int virtio_net_can_receive(VLANClientState *nc)
{
VirtIONet *n = DO_UPCAST(NICState, nc, nc)->opaque;
if (!virtio_queue_ready(n->rx_vq) ||
!(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK))
return 0;
return 1;
}
static int virtio_net_has_buffers(VirtIONet *n, int bufsize)
{
if (virtio_queue_empty(n->rx_vq) ||
(n->mergeable_rx_bufs &&
!virtqueue_avail_bytes(n->rx_vq, bufsize, 0))) {
virtio_queue_set_notification(n->rx_vq, 1);
/* To avoid a race condition where the guest has made some buffers
* available after the above check but before notification was
* enabled, check for available buffers again.
*/
if (virtio_queue_empty(n->rx_vq) ||
(n->mergeable_rx_bufs &&
!virtqueue_avail_bytes(n->rx_vq, bufsize, 0)))
return 0;
}
virtio_queue_set_notification(n->rx_vq, 0);
return 1;
}
/* dhclient uses AF_PACKET but doesn't pass auxdata to the kernel so
* it never finds out that the packets don't have valid checksums. This
* causes dhclient to get upset. Fedora's carried a patch for ages to
* fix this with Xen but it hasn't appeared in an upstream release of
* dhclient yet.
*
* To avoid breaking existing guests, we catch udp packets and add
* checksums. This is terrible but it's better than hacking the guest
* kernels.
*
* N.B. if we introduce a zero-copy API, this operation is no longer free so
* we should provide a mechanism to disable it to avoid polluting the host
* cache.
*/
static void work_around_broken_dhclient(struct virtio_net_hdr *hdr,
const uint8_t *buf, size_t size)
{
if ((hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && /* missing csum */
(size > 27 && size < 1500) && /* normal sized MTU */
(buf[12] == 0x08 && buf[13] == 0x00) && /* ethertype == IPv4 */
(buf[23] == 17) && /* ip.protocol == UDP */
(buf[34] == 0 && buf[35] == 67)) { /* udp.srcport == bootps */
/* FIXME this cast is evil */
net_checksum_calculate((uint8_t *)buf, size);
hdr->flags &= ~VIRTIO_NET_HDR_F_NEEDS_CSUM;
}
}
static int receive_header(VirtIONet *n, struct iovec *iov, int iovcnt,
const void *buf, size_t size, size_t hdr_len)
{
struct virtio_net_hdr *hdr = (struct virtio_net_hdr *)iov[0].iov_base;
int offset = 0;
hdr->flags = 0;
hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
if (n->has_vnet_hdr) {
memcpy(hdr, buf, sizeof(*hdr));
offset = sizeof(*hdr);
work_around_broken_dhclient(hdr, buf + offset, size - offset);
}
/* We only ever receive a struct virtio_net_hdr from the tapfd,
* but we may be passing along a larger header to the guest.
*/
iov[0].iov_base += hdr_len;
iov[0].iov_len -= hdr_len;
return offset;
}
static int receive_filter(VirtIONet *n, const uint8_t *buf, int size)
{
static const uint8_t bcast[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
static const uint8_t vlan[] = {0x81, 0x00};
uint8_t *ptr = (uint8_t *)buf;
int i;
if (n->promisc)
return 1;
if (n->has_vnet_hdr) {
ptr += sizeof(struct virtio_net_hdr);
}
if (!memcmp(&ptr[12], vlan, sizeof(vlan))) {
int vid = be16_to_cpup((uint16_t *)(ptr + 14)) & 0xfff;
if (!(n->vlans[vid >> 5] & (1U << (vid & 0x1f))))
return 0;
}
if (ptr[0] & 1) { // multicast
if (!memcmp(ptr, bcast, sizeof(bcast))) {
return !n->nobcast;
} else if (n->nomulti) {
return 0;
} else if (n->allmulti || n->mac_table.multi_overflow) {
return 1;
}
for (i = n->mac_table.first_multi; i < n->mac_table.in_use; i++) {
if (!memcmp(ptr, &n->mac_table.macs[i * ETH_ALEN], ETH_ALEN)) {
return 1;
}
}
} else { // unicast
if (n->nouni) {
return 0;
} else if (n->alluni || n->mac_table.uni_overflow) {
return 1;
} else if (!memcmp(ptr, n->mac, ETH_ALEN)) {
return 1;
}
for (i = 0; i < n->mac_table.first_multi; i++) {
if (!memcmp(ptr, &n->mac_table.macs[i * ETH_ALEN], ETH_ALEN)) {
return 1;
}
}
}
return 0;
}
static ssize_t virtio_net_receive(VLANClientState *nc, const uint8_t *buf, size_t size)
{
VirtIONet *n = DO_UPCAST(NICState, nc, nc)->opaque;
struct virtio_net_hdr_mrg_rxbuf *mhdr = NULL;
size_t guest_hdr_len, offset, i, host_hdr_len;
if (!virtio_net_can_receive(&n->nic->nc))
return -1;
/* hdr_len refers to the header we supply to the guest */
guest_hdr_len = n->mergeable_rx_bufs ?
sizeof(struct virtio_net_hdr_mrg_rxbuf) : sizeof(struct virtio_net_hdr);
host_hdr_len = n->has_vnet_hdr ? sizeof(struct virtio_net_hdr) : 0;
if (!virtio_net_has_buffers(n, size + guest_hdr_len - host_hdr_len))
return 0;
if (!receive_filter(n, buf, size))
return size;
offset = i = 0;
while (offset < size) {
VirtQueueElement elem;
int len, total;
struct iovec sg[VIRTQUEUE_MAX_SIZE];
total = 0;
if (virtqueue_pop(n->rx_vq, &elem) == 0) {
if (i == 0)
return -1;
fprintf(stderr, "virtio-net unexpected empty queue: "
"i %zd mergeable %d offset %zd, size %zd, "
"guest hdr len %zd, host hdr len %zd guest features 0x%x\n",
i, n->mergeable_rx_bufs, offset, size,
guest_hdr_len, host_hdr_len, n->vdev.guest_features);
exit(1);
}
if (elem.in_num < 1) {
fprintf(stderr, "virtio-net receive queue contains no in buffers\n");
exit(1);
}
if (!n->mergeable_rx_bufs && elem.in_sg[0].iov_len != guest_hdr_len) {
fprintf(stderr, "virtio-net header not in first element\n");
exit(1);
}
memcpy(&sg, &elem.in_sg[0], sizeof(sg[0]) * elem.in_num);
if (i == 0) {
if (n->mergeable_rx_bufs)
mhdr = (struct virtio_net_hdr_mrg_rxbuf *)sg[0].iov_base;
offset += receive_header(n, sg, elem.in_num,
buf + offset, size - offset, guest_hdr_len);
total += guest_hdr_len;
}
/* copy in packet. ugh */
len = iov_from_buf(sg, elem.in_num,
buf + offset, size - offset);
total += len;
offset += len;
/* If buffers can't be merged, at this point we
* must have consumed the complete packet.
* Otherwise, drop it. */
if (!n->mergeable_rx_bufs && offset < size) {
#if 0
fprintf(stderr, "virtio-net truncated non-mergeable packet: "
"i %zd mergeable %d offset %zd, size %zd, "
"guest hdr len %zd, host hdr len %zd\n",
i, n->mergeable_rx_bufs,
offset, size, guest_hdr_len, host_hdr_len);
#endif
return size;
}
/* signal other side */
virtqueue_fill(n->rx_vq, &elem, total, i++);
}
if (mhdr)
mhdr->num_buffers = i;
virtqueue_flush(n->rx_vq, i);
virtio_notify(&n->vdev, n->rx_vq);
return size;
}
static int32_t virtio_net_flush_tx(VirtIONet *n, VirtQueue *vq);
static void virtio_net_tx_complete(VLANClientState *nc, ssize_t len)
{
VirtIONet *n = DO_UPCAST(NICState, nc, nc)->opaque;
virtqueue_push(n->tx_vq, &n->async_tx.elem, n->async_tx.len);
virtio_notify(&n->vdev, n->tx_vq);
n->async_tx.elem.out_num = n->async_tx.len = 0;
virtio_queue_set_notification(n->tx_vq, 1);
virtio_net_flush_tx(n, n->tx_vq);
}
/* TX */
static int32_t virtio_net_flush_tx(VirtIONet *n, VirtQueue *vq)
{
VirtQueueElement elem;
int32_t num_packets = 0;
if (!(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK)) {
return num_packets;
}
if (n->async_tx.elem.out_num) {
virtio_queue_set_notification(n->tx_vq, 0);
return num_packets;
}
while (virtqueue_pop(vq, &elem)) {
ssize_t ret, len = 0;
unsigned int out_num = elem.out_num;
struct iovec *out_sg = &elem.out_sg[0];
unsigned hdr_len;
/* hdr_len refers to the header received from the guest */
hdr_len = n->mergeable_rx_bufs ?
sizeof(struct virtio_net_hdr_mrg_rxbuf) :
sizeof(struct virtio_net_hdr);
if (out_num < 1 || out_sg->iov_len != hdr_len) {
fprintf(stderr, "virtio-net header not in first element\n");
exit(1);
}
/* ignore the header if GSO is not supported */
if (!n->has_vnet_hdr) {
out_num--;
out_sg++;
len += hdr_len;
} else if (n->mergeable_rx_bufs) {
/* tapfd expects a struct virtio_net_hdr */
hdr_len -= sizeof(struct virtio_net_hdr);
out_sg->iov_len -= hdr_len;
len += hdr_len;
}
ret = qemu_sendv_packet_async(&n->nic->nc, out_sg, out_num,
virtio_net_tx_complete);
if (ret == 0) {
virtio_queue_set_notification(n->tx_vq, 0);
n->async_tx.elem = elem;
n->async_tx.len = len;
return -EBUSY;
}
len += ret;
virtqueue_push(vq, &elem, len);
virtio_notify(&n->vdev, vq);
if (++num_packets >= n->tx_burst) {
break;
}
}
return num_packets;
}
static void virtio_net_handle_tx_timer(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIONet *n = to_virtio_net(vdev);
if (n->tx_waiting) {
virtio_queue_set_notification(vq, 1);
qemu_del_timer(n->tx_timer);
n->tx_waiting = 0;
virtio_net_flush_tx(n, vq);
} else {
qemu_mod_timer(n->tx_timer,
qemu_get_clock(vm_clock) + n->tx_timeout);
n->tx_waiting = 1;
virtio_queue_set_notification(vq, 0);
}
}
static void virtio_net_handle_tx_bh(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIONet *n = to_virtio_net(vdev);
if (unlikely(n->tx_waiting)) {
return;
}
virtio_queue_set_notification(vq, 0);
qemu_bh_schedule(n->tx_bh);
n->tx_waiting = 1;
}
static void virtio_net_tx_timer(void *opaque)
{
VirtIONet *n = opaque;
n->tx_waiting = 0;
/* Just in case the driver is not ready on more */
if (!(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK))
return;
virtio_queue_set_notification(n->tx_vq, 1);
virtio_net_flush_tx(n, n->tx_vq);
}
static void virtio_net_tx_bh(void *opaque)
{
VirtIONet *n = opaque;
int32_t ret;
n->tx_waiting = 0;
/* Just in case the driver is not ready on more */
if (unlikely(!(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK)))
return;
ret = virtio_net_flush_tx(n, n->tx_vq);
if (ret == -EBUSY) {
return; /* Notification re-enable handled by tx_complete */
}
/* If we flush a full burst of packets, assume there are
* more coming and immediately reschedule */
if (ret >= n->tx_burst) {
qemu_bh_schedule(n->tx_bh);
n->tx_waiting = 1;
return;
}
/* If less than a full burst, re-enable notification and flush
* anything that may have come in while we weren't looking. If
* we find something, assume the guest is still active and reschedule */
virtio_queue_set_notification(n->tx_vq, 1);
if (virtio_net_flush_tx(n, n->tx_vq) > 0) {
virtio_queue_set_notification(n->tx_vq, 0);
qemu_bh_schedule(n->tx_bh);
n->tx_waiting = 1;
}
}
static void virtio_net_save(QEMUFile *f, void *opaque)
{
VirtIONet *n = opaque;
if (n->vhost_started) {
/* TODO: should we really stop the backend?
* If we don't, it might keep writing to memory. */
vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), &n->vdev);
n->vhost_started = 0;
}
virtio_save(&n->vdev, f);
qemu_put_buffer(f, n->mac, ETH_ALEN);
qemu_put_be32(f, n->tx_waiting);
qemu_put_be32(f, n->mergeable_rx_bufs);
qemu_put_be16(f, n->status);
qemu_put_byte(f, n->promisc);
qemu_put_byte(f, n->allmulti);
qemu_put_be32(f, n->mac_table.in_use);
qemu_put_buffer(f, n->mac_table.macs, n->mac_table.in_use * ETH_ALEN);
qemu_put_buffer(f, (uint8_t *)n->vlans, MAX_VLAN >> 3);
qemu_put_be32(f, n->has_vnet_hdr);
qemu_put_byte(f, n->mac_table.multi_overflow);
qemu_put_byte(f, n->mac_table.uni_overflow);
qemu_put_byte(f, n->alluni);
qemu_put_byte(f, n->nomulti);
qemu_put_byte(f, n->nouni);
qemu_put_byte(f, n->nobcast);
qemu_put_byte(f, n->has_ufo);
}
static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
{
VirtIONet *n = opaque;
int i;
if (version_id < 2 || version_id > VIRTIO_NET_VM_VERSION)
return -EINVAL;
virtio_load(&n->vdev, f);
qemu_get_buffer(f, n->mac, ETH_ALEN);
n->tx_waiting = qemu_get_be32(f);
n->mergeable_rx_bufs = qemu_get_be32(f);
if (version_id >= 3)
n->status = qemu_get_be16(f);
if (version_id >= 4) {
if (version_id < 8) {
n->promisc = qemu_get_be32(f);
n->allmulti = qemu_get_be32(f);
} else {
n->promisc = qemu_get_byte(f);
n->allmulti = qemu_get_byte(f);
}
}
if (version_id >= 5) {
n->mac_table.in_use = qemu_get_be32(f);
/* MAC_TABLE_ENTRIES may be different from the saved image */
if (n->mac_table.in_use <= MAC_TABLE_ENTRIES) {
qemu_get_buffer(f, n->mac_table.macs,
n->mac_table.in_use * ETH_ALEN);
} else if (n->mac_table.in_use) {
qemu_fseek(f, n->mac_table.in_use * ETH_ALEN, SEEK_CUR);
n->mac_table.multi_overflow = n->mac_table.uni_overflow = 1;
n->mac_table.in_use = 0;
}
}
if (version_id >= 6)
qemu_get_buffer(f, (uint8_t *)n->vlans, MAX_VLAN >> 3);
if (version_id >= 7) {
if (qemu_get_be32(f) && !peer_has_vnet_hdr(n)) {
error_report("virtio-net: saved image requires vnet_hdr=on");
return -1;
}
if (n->has_vnet_hdr) {
tap_using_vnet_hdr(n->nic->nc.peer, 1);
tap_set_offload(n->nic->nc.peer,
(n->vdev.guest_features >> VIRTIO_NET_F_GUEST_CSUM) & 1,
(n->vdev.guest_features >> VIRTIO_NET_F_GUEST_TSO4) & 1,
(n->vdev.guest_features >> VIRTIO_NET_F_GUEST_TSO6) & 1,
(n->vdev.guest_features >> VIRTIO_NET_F_GUEST_ECN) & 1,
(n->vdev.guest_features >> VIRTIO_NET_F_GUEST_UFO) & 1);
}
}
if (version_id >= 9) {
n->mac_table.multi_overflow = qemu_get_byte(f);
n->mac_table.uni_overflow = qemu_get_byte(f);
}
if (version_id >= 10) {
n->alluni = qemu_get_byte(f);
n->nomulti = qemu_get_byte(f);
n->nouni = qemu_get_byte(f);
n->nobcast = qemu_get_byte(f);
}
if (version_id >= 11) {
if (qemu_get_byte(f) && !peer_has_ufo(n)) {
error_report("virtio-net: saved image requires TUN_F_UFO support");
return -1;
}
}
/* Find the first multicast entry in the saved MAC filter */
for (i = 0; i < n->mac_table.in_use; i++) {
if (n->mac_table.macs[i * ETH_ALEN] & 1) {
break;
}
}
n->mac_table.first_multi = i;
if (n->tx_waiting) {
if (n->tx_timer) {
qemu_mod_timer(n->tx_timer,
qemu_get_clock(vm_clock) + n->tx_timeout);
} else {
qemu_bh_schedule(n->tx_bh);
}
}
return 0;
}
static void virtio_net_cleanup(VLANClientState *nc)
{
VirtIONet *n = DO_UPCAST(NICState, nc, nc)->opaque;
n->nic = NULL;
}
static NetClientInfo net_virtio_info = {
.type = NET_CLIENT_TYPE_NIC,
.size = sizeof(NICState),
.can_receive = virtio_net_can_receive,
.receive = virtio_net_receive,
.cleanup = virtio_net_cleanup,
.link_status_changed = virtio_net_set_link_status,
};
static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t status)
{
VirtIONet *n = to_virtio_net(vdev);
if (!n->nic->nc.peer) {
return;
}
if (n->nic->nc.peer->info->type != NET_CLIENT_TYPE_TAP) {
return;
}
if (!tap_get_vhost_net(n->nic->nc.peer)) {
return;
}
if (!!n->vhost_started == !!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
return;
}
if (status & VIRTIO_CONFIG_S_DRIVER_OK) {
int r = vhost_net_start(tap_get_vhost_net(n->nic->nc.peer), vdev);
if (r < 0) {
fprintf(stderr, "unable to start vhost net: %d: "
"falling back on userspace virtio\n", -r);
} else {
n->vhost_started = 1;
}
} else {
vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), vdev);
n->vhost_started = 0;
}
}
static void virtio_net_vmstate_change(void *opaque, int running, int reason)
{
VirtIONet *n = opaque;
uint8_t status = running ? VIRTIO_CONFIG_S_DRIVER_OK : 0;
/* This is called when vm is started/stopped,
* it will start/stop vhost backend if * appropriate
* e.g. after migration. */
virtio_net_set_status(&n->vdev, n->vdev.status & status);
}
VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf,
virtio_net_conf *net)
{
VirtIONet *n;
n = (VirtIONet *)virtio_common_init("virtio-net", VIRTIO_ID_NET,
sizeof(struct virtio_net_config),
sizeof(VirtIONet));
n->vdev.get_config = virtio_net_get_config;
n->vdev.set_config = virtio_net_set_config;
n->vdev.get_features = virtio_net_get_features;
n->vdev.set_features = virtio_net_set_features;
n->vdev.bad_features = virtio_net_bad_features;
n->vdev.reset = virtio_net_reset;
n->vdev.set_status = virtio_net_set_status;
n->rx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_rx);
if (net->tx && strcmp(net->tx, "timer") && strcmp(net->tx, "bh")) {
fprintf(stderr, "virtio-net: "
"Unknown option tx=%s, valid options: \"timer\" \"bh\"\n",
net->tx);
fprintf(stderr, "Defaulting to \"bh\"\n");
}
if (net->tx && !strcmp(net->tx, "timer")) {
n->tx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_tx_timer);
n->tx_timer = qemu_new_timer(vm_clock, virtio_net_tx_timer, n);
n->tx_timeout = net->txtimer;
} else {
n->tx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_tx_bh);
n->tx_bh = qemu_bh_new(virtio_net_tx_bh, n);
}
n->ctrl_vq = virtio_add_queue(&n->vdev, 64, virtio_net_handle_ctrl);
qemu_macaddr_default_if_unset(&conf->macaddr);
memcpy(&n->mac[0], &conf->macaddr, sizeof(n->mac));
n->status = VIRTIO_NET_S_LINK_UP;
n->nic = qemu_new_nic(&net_virtio_info, conf, dev->info->name, dev->id, n);
qemu_format_nic_info_str(&n->nic->nc, conf->macaddr.a);
n->tx_waiting = 0;
n->tx_burst = net->txburst;
n->mergeable_rx_bufs = 0;
n->promisc = 1; /* for compatibility */
n->mac_table.macs = qemu_mallocz(MAC_TABLE_ENTRIES * ETH_ALEN);
n->vlans = qemu_mallocz(MAX_VLAN >> 3);
n->qdev = dev;
register_savevm(dev, "virtio-net", -1, VIRTIO_NET_VM_VERSION,
virtio_net_save, virtio_net_load, n);
n->vmstate = qemu_add_vm_change_state_handler(virtio_net_vmstate_change, n);
return &n->vdev;
}
void virtio_net_exit(VirtIODevice *vdev)
{
VirtIONet *n = DO_UPCAST(VirtIONet, vdev, vdev);
qemu_del_vm_change_state_handler(n->vmstate);
if (n->vhost_started) {
vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), vdev);
}
qemu_purge_queued_packets(&n->nic->nc);
unregister_savevm(n->qdev, "virtio-net", n);
qemu_free(n->mac_table.macs);
qemu_free(n->vlans);
if (n->tx_timer) {
qemu_del_timer(n->tx_timer);
qemu_free_timer(n->tx_timer);
} else {
qemu_bh_delete(n->tx_bh);
}
virtio_cleanup(&n->vdev);
qemu_del_vlan_client(&n->nic->nc);
}
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