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qemu/hw/xen_nic.c
Paolo Bonzini a98b140223 xen: flush queue when getting an event 
xen does not have a register that, when written, will cause can_receive
to go from false to true.  However, flushing the queue can be attempted
whenever the front-end raises its side of the Xen event channel.  There
is a single event channel for tx and rx.

Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Amos Kong <akong@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2012-09-14 08:40:31 +01:00

440 lines
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/*
* xen paravirt network card backend
*
* (c) Gerd Hoffmann <kraxel@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; under version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, see <http://www.gnu.org/licenses/>.
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <inttypes.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include "hw.h"
#include "net.h"
#include "net/checksum.h"
#include "net/util.h"
#include "qemu-char.h"
#include "xen_backend.h"
#include <xen/io/netif.h>
/* ------------------------------------------------------------- */
struct XenNetDev {
struct XenDevice xendev; /* must be first */
char *mac;
int tx_work;
int tx_ring_ref;
int rx_ring_ref;
struct netif_tx_sring *txs;
struct netif_rx_sring *rxs;
netif_tx_back_ring_t tx_ring;
netif_rx_back_ring_t rx_ring;
NICConf conf;
NICState *nic;
};
/* ------------------------------------------------------------- */
static void net_tx_response(struct XenNetDev *netdev, netif_tx_request_t *txp, int8_t st)
{
RING_IDX i = netdev->tx_ring.rsp_prod_pvt;
netif_tx_response_t *resp;
int notify;
resp = RING_GET_RESPONSE(&netdev->tx_ring, i);
resp->id = txp->id;
resp->status = st;
#if 0
if (txp->flags & NETTXF_extra_info) {
RING_GET_RESPONSE(&netdev->tx_ring, ++i)->status = NETIF_RSP_NULL;
}
#endif
netdev->tx_ring.rsp_prod_pvt = ++i;
RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&netdev->tx_ring, notify);
if (notify) {
xen_be_send_notify(&netdev->xendev);
}
if (i == netdev->tx_ring.req_cons) {
int more_to_do;
RING_FINAL_CHECK_FOR_REQUESTS(&netdev->tx_ring, more_to_do);
if (more_to_do) {
netdev->tx_work++;
}
}
}
static void net_tx_error(struct XenNetDev *netdev, netif_tx_request_t *txp, RING_IDX end)
{
#if 0
/*
* Hmm, why netback fails everything in the ring?
* Should we do that even when not supporting SG and TSO?
*/
RING_IDX cons = netdev->tx_ring.req_cons;
do {
make_tx_response(netif, txp, NETIF_RSP_ERROR);
if (cons >= end) {
break;
}
txp = RING_GET_REQUEST(&netdev->tx_ring, cons++);
} while (1);
netdev->tx_ring.req_cons = cons;
netif_schedule_work(netif);
netif_put(netif);
#else
net_tx_response(netdev, txp, NETIF_RSP_ERROR);
#endif
}
static void net_tx_packets(struct XenNetDev *netdev)
{
netif_tx_request_t txreq;
RING_IDX rc, rp;
void *page;
void *tmpbuf = NULL;
for (;;) {
rc = netdev->tx_ring.req_cons;
rp = netdev->tx_ring.sring->req_prod;
xen_rmb(); /* Ensure we see queued requests up to 'rp'. */
while ((rc != rp)) {
if (RING_REQUEST_CONS_OVERFLOW(&netdev->tx_ring, rc)) {
break;
}
memcpy(&txreq, RING_GET_REQUEST(&netdev->tx_ring, rc), sizeof(txreq));
netdev->tx_ring.req_cons = ++rc;
#if 1
/* should not happen in theory, we don't announce the *
* feature-{sg,gso,whatelse} flags in xenstore (yet?) */
if (txreq.flags & NETTXF_extra_info) {
xen_be_printf(&netdev->xendev, 0, "FIXME: extra info flag\n");
net_tx_error(netdev, &txreq, rc);
continue;
}
if (txreq.flags & NETTXF_more_data) {
xen_be_printf(&netdev->xendev, 0, "FIXME: more data flag\n");
net_tx_error(netdev, &txreq, rc);
continue;
}
#endif
if (txreq.size < 14) {
xen_be_printf(&netdev->xendev, 0, "bad packet size: %d\n", txreq.size);
net_tx_error(netdev, &txreq, rc);
continue;
}
if ((txreq.offset + txreq.size) > XC_PAGE_SIZE) {
xen_be_printf(&netdev->xendev, 0, "error: page crossing\n");
net_tx_error(netdev, &txreq, rc);
continue;
}
xen_be_printf(&netdev->xendev, 3, "tx packet ref %d, off %d, len %d, flags 0x%x%s%s%s%s\n",
txreq.gref, txreq.offset, txreq.size, txreq.flags,
(txreq.flags & NETTXF_csum_blank) ? " csum_blank" : "",
(txreq.flags & NETTXF_data_validated) ? " data_validated" : "",
(txreq.flags & NETTXF_more_data) ? " more_data" : "",
(txreq.flags & NETTXF_extra_info) ? " extra_info" : "");
page = xc_gnttab_map_grant_ref(netdev->xendev.gnttabdev,
netdev->xendev.dom,
txreq.gref, PROT_READ);
if (page == NULL) {
xen_be_printf(&netdev->xendev, 0, "error: tx gref dereference failed (%d)\n",
txreq.gref);
net_tx_error(netdev, &txreq, rc);
continue;
}
if (txreq.flags & NETTXF_csum_blank) {
/* have read-only mapping -> can't fill checksum in-place */
if (!tmpbuf) {
tmpbuf = g_malloc(XC_PAGE_SIZE);
}
memcpy(tmpbuf, page + txreq.offset, txreq.size);
net_checksum_calculate(tmpbuf, txreq.size);
qemu_send_packet(&netdev->nic->nc, tmpbuf, txreq.size);
} else {
qemu_send_packet(&netdev->nic->nc, page + txreq.offset, txreq.size);
}
xc_gnttab_munmap(netdev->xendev.gnttabdev, page, 1);
net_tx_response(netdev, &txreq, NETIF_RSP_OKAY);
}
if (!netdev->tx_work) {
break;
}
netdev->tx_work = 0;
}
g_free(tmpbuf);
}
/* ------------------------------------------------------------- */
static void net_rx_response(struct XenNetDev *netdev,
netif_rx_request_t *req, int8_t st,
uint16_t offset, uint16_t size,
uint16_t flags)
{
RING_IDX i = netdev->rx_ring.rsp_prod_pvt;
netif_rx_response_t *resp;
int notify;
resp = RING_GET_RESPONSE(&netdev->rx_ring, i);
resp->offset = offset;
resp->flags = flags;
resp->id = req->id;
resp->status = (int16_t)size;
if (st < 0) {
resp->status = (int16_t)st;
}
xen_be_printf(&netdev->xendev, 3, "rx response: idx %d, status %d, flags 0x%x\n",
i, resp->status, resp->flags);
netdev->rx_ring.rsp_prod_pvt = ++i;
RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&netdev->rx_ring, notify);
if (notify) {
xen_be_send_notify(&netdev->xendev);
}
}
#define NET_IP_ALIGN 2
static int net_rx_ok(NetClientState *nc)
{
struct XenNetDev *netdev = DO_UPCAST(NICState, nc, nc)->opaque;
RING_IDX rc, rp;
if (netdev->xendev.be_state != XenbusStateConnected) {
return 0;
}
rc = netdev->rx_ring.req_cons;
rp = netdev->rx_ring.sring->req_prod;
xen_rmb();
if (rc == rp || RING_REQUEST_CONS_OVERFLOW(&netdev->rx_ring, rc)) {
xen_be_printf(&netdev->xendev, 2, "%s: no rx buffers (%d/%d)\n",
__FUNCTION__, rc, rp);
return 0;
}
return 1;
}
static ssize_t net_rx_packet(NetClientState *nc, const uint8_t *buf, size_t size)
{
struct XenNetDev *netdev = DO_UPCAST(NICState, nc, nc)->opaque;
netif_rx_request_t rxreq;
RING_IDX rc, rp;
void *page;
if (netdev->xendev.be_state != XenbusStateConnected) {
return -1;
}
rc = netdev->rx_ring.req_cons;
rp = netdev->rx_ring.sring->req_prod;
xen_rmb(); /* Ensure we see queued requests up to 'rp'. */
if (rc == rp || RING_REQUEST_CONS_OVERFLOW(&netdev->rx_ring, rc)) {
xen_be_printf(&netdev->xendev, 2, "no buffer, drop packet\n");
return -1;
}
if (size > XC_PAGE_SIZE - NET_IP_ALIGN) {
xen_be_printf(&netdev->xendev, 0, "packet too big (%lu > %ld)",
(unsigned long)size, XC_PAGE_SIZE - NET_IP_ALIGN);
return -1;
}
memcpy(&rxreq, RING_GET_REQUEST(&netdev->rx_ring, rc), sizeof(rxreq));
netdev->rx_ring.req_cons = ++rc;
page = xc_gnttab_map_grant_ref(netdev->xendev.gnttabdev,
netdev->xendev.dom,
rxreq.gref, PROT_WRITE);
if (page == NULL) {
xen_be_printf(&netdev->xendev, 0, "error: rx gref dereference failed (%d)\n",
rxreq.gref);
net_rx_response(netdev, &rxreq, NETIF_RSP_ERROR, 0, 0, 0);
return -1;
}
memcpy(page + NET_IP_ALIGN, buf, size);
xc_gnttab_munmap(netdev->xendev.gnttabdev, page, 1);
net_rx_response(netdev, &rxreq, NETIF_RSP_OKAY, NET_IP_ALIGN, size, 0);
return size;
}
/* ------------------------------------------------------------- */
static NetClientInfo net_xen_info = {
.type = NET_CLIENT_OPTIONS_KIND_NIC,
.size = sizeof(NICState),
.can_receive = net_rx_ok,
.receive = net_rx_packet,
};
static int net_init(struct XenDevice *xendev)
{
struct XenNetDev *netdev = container_of(xendev, struct XenNetDev, xendev);
/* read xenstore entries */
if (netdev->mac == NULL) {
netdev->mac = xenstore_read_be_str(&netdev->xendev, "mac");
}
/* do we have all we need? */
if (netdev->mac == NULL) {
return -1;
}
if (net_parse_macaddr(netdev->conf.macaddr.a, netdev->mac) < 0) {
return -1;
}
netdev->conf.peer = NULL;
netdev->nic = qemu_new_nic(&net_xen_info, &netdev->conf,
"xen", NULL, netdev);
snprintf(netdev->nic->nc.info_str, sizeof(netdev->nic->nc.info_str),
"nic: xenbus vif macaddr=%s", netdev->mac);
/* fill info */
xenstore_write_be_int(&netdev->xendev, "feature-rx-copy", 1);
xenstore_write_be_int(&netdev->xendev, "feature-rx-flip", 0);
return 0;
}
static int net_connect(struct XenDevice *xendev)
{
struct XenNetDev *netdev = container_of(xendev, struct XenNetDev, xendev);
int rx_copy;
if (xenstore_read_fe_int(&netdev->xendev, "tx-ring-ref",
&netdev->tx_ring_ref) == -1) {
return -1;
}
if (xenstore_read_fe_int(&netdev->xendev, "rx-ring-ref",
&netdev->rx_ring_ref) == -1) {
return 1;
}
if (xenstore_read_fe_int(&netdev->xendev, "event-channel",
&netdev->xendev.remote_port) == -1) {
return -1;
}
if (xenstore_read_fe_int(&netdev->xendev, "request-rx-copy", &rx_copy) == -1) {
rx_copy = 0;
}
if (rx_copy == 0) {
xen_be_printf(&netdev->xendev, 0, "frontend doesn't support rx-copy.\n");
return -1;
}
netdev->txs = xc_gnttab_map_grant_ref(netdev->xendev.gnttabdev,
netdev->xendev.dom,
netdev->tx_ring_ref,
PROT_READ | PROT_WRITE);
netdev->rxs = xc_gnttab_map_grant_ref(netdev->xendev.gnttabdev,
netdev->xendev.dom,
netdev->rx_ring_ref,
PROT_READ | PROT_WRITE);
if (!netdev->txs || !netdev->rxs) {
return -1;
}
BACK_RING_INIT(&netdev->tx_ring, netdev->txs, XC_PAGE_SIZE);
BACK_RING_INIT(&netdev->rx_ring, netdev->rxs, XC_PAGE_SIZE);
xen_be_bind_evtchn(&netdev->xendev);
xen_be_printf(&netdev->xendev, 1, "ok: tx-ring-ref %d, rx-ring-ref %d, "
"remote port %d, local port %d\n",
netdev->tx_ring_ref, netdev->rx_ring_ref,
netdev->xendev.remote_port, netdev->xendev.local_port);
net_tx_packets(netdev);
return 0;
}
static void net_disconnect(struct XenDevice *xendev)
{
struct XenNetDev *netdev = container_of(xendev, struct XenNetDev, xendev);
xen_be_unbind_evtchn(&netdev->xendev);
if (netdev->txs) {
xc_gnttab_munmap(netdev->xendev.gnttabdev, netdev->txs, 1);
netdev->txs = NULL;
}
if (netdev->rxs) {
xc_gnttab_munmap(netdev->xendev.gnttabdev, netdev->rxs, 1);
netdev->rxs = NULL;
}
if (netdev->nic) {
qemu_del_net_client(&netdev->nic->nc);
netdev->nic = NULL;
}
}
static void net_event(struct XenDevice *xendev)
{
struct XenNetDev *netdev = container_of(xendev, struct XenNetDev, xendev);
net_tx_packets(netdev);
qemu_flush_queued_packets(&netdev->nic->nc);
}
static int net_free(struct XenDevice *xendev)
{
struct XenNetDev *netdev = container_of(xendev, struct XenNetDev, xendev);
g_free(netdev->mac);
return 0;
}
/* ------------------------------------------------------------- */
struct XenDevOps xen_netdev_ops = {
.size = sizeof(struct XenNetDev),
.flags = DEVOPS_FLAG_NEED_GNTDEV,
.init = net_init,
.initialise = net_connect,
.event = net_event,
.disconnect = net_disconnect,
.free = net_free,
};
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