qemu/net/vhost-user.c
Eric Blake 32bafa8fdd qapi: Don't special-case simple union wrappers
Simple unions were carrying a special case that hid their 'data'
QMP member from the resulting C struct, via the hack method
QAPISchemaObjectTypeVariant.simple_union_type().  But by using
the work we started by unboxing flat union and alternate
branches, coupled with the ability to visit the members of an
implicit type, we can now expose the simple union's implicit
type in qapi-types.h:

| struct q_obj_ImageInfoSpecificQCow2_wrapper {
|     ImageInfoSpecificQCow2 *data;
| };
|
| struct q_obj_ImageInfoSpecificVmdk_wrapper {
|     ImageInfoSpecificVmdk *data;
| };
...
| struct ImageInfoSpecific {
|     ImageInfoSpecificKind type;
|     union { /* union tag is @type */
|         void *data;
|-        ImageInfoSpecificQCow2 *qcow2;
|-        ImageInfoSpecificVmdk *vmdk;
|+        q_obj_ImageInfoSpecificQCow2_wrapper qcow2;
|+        q_obj_ImageInfoSpecificVmdk_wrapper vmdk;
|     } u;
| };

Doing this removes asymmetry between QAPI's QMP side and its
C side (both sides now expose 'data'), and means that the
treatment of a simple union as sugar for a flat union is now
equivalent in both languages (previously the two approaches used
a different layer of dereferencing, where the simple union could
be converted to a flat union with equivalent C layout but
different {} on the wire, or to an equivalent QMP wire form
but with different C representation).  Using the implicit type
also lets us get rid of the simple_union_type() hack.

Of course, now all clients of simple unions have to adjust from
using su->u.member to using su->u.member.data; while this touches
a number of files in the tree, some earlier cleanup patches
helped minimize the change to the initialization of a temporary
variable rather than every single member access.  The generated
qapi-visit.c code is also affected by the layout change:

|@@ -7393,10 +7393,10 @@ void visit_type_ImageInfoSpecific_member
|     }
|     switch (obj->type) {
|     case IMAGE_INFO_SPECIFIC_KIND_QCOW2:
|-        visit_type_ImageInfoSpecificQCow2(v, "data", &obj->u.qcow2, &err);
|+        visit_type_q_obj_ImageInfoSpecificQCow2_wrapper_members(v, &obj->u.qcow2, &err);
|         break;
|     case IMAGE_INFO_SPECIFIC_KIND_VMDK:
|-        visit_type_ImageInfoSpecificVmdk(v, "data", &obj->u.vmdk, &err);
|+        visit_type_q_obj_ImageInfoSpecificVmdk_wrapper_members(v, &obj->u.vmdk, &err);
|         break;
|     default:
|         abort();

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1458254921-17042-13-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-03-18 10:29:26 +01:00

332 lines
8.5 KiB
C

/*
* vhost-user.c
*
* Copyright (c) 2013 Virtual Open Systems Sarl.
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "clients.h"
#include "net/vhost_net.h"
#include "net/vhost-user.h"
#include "sysemu/char.h"
#include "qemu/config-file.h"
#include "qemu/error-report.h"
#include "qmp-commands.h"
#include "trace.h"
typedef struct VhostUserState {
NetClientState nc;
CharDriverState *chr;
VHostNetState *vhost_net;
} VhostUserState;
typedef struct VhostUserChardevProps {
bool is_socket;
bool is_unix;
} VhostUserChardevProps;
VHostNetState *vhost_user_get_vhost_net(NetClientState *nc)
{
VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
return s->vhost_net;
}
static int vhost_user_running(VhostUserState *s)
{
return (s->vhost_net) ? 1 : 0;
}
static void vhost_user_stop(int queues, NetClientState *ncs[])
{
VhostUserState *s;
int i;
for (i = 0; i < queues; i++) {
assert (ncs[i]->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
s = DO_UPCAST(VhostUserState, nc, ncs[i]);
if (!vhost_user_running(s)) {
continue;
}
if (s->vhost_net) {
vhost_net_cleanup(s->vhost_net);
s->vhost_net = NULL;
}
}
}
static int vhost_user_start(int queues, NetClientState *ncs[])
{
VhostNetOptions options;
VhostUserState *s;
int max_queues;
int i;
options.backend_type = VHOST_BACKEND_TYPE_USER;
for (i = 0; i < queues; i++) {
assert (ncs[i]->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
s = DO_UPCAST(VhostUserState, nc, ncs[i]);
if (vhost_user_running(s)) {
continue;
}
options.net_backend = ncs[i];
options.opaque = s->chr;
s->vhost_net = vhost_net_init(&options);
if (!s->vhost_net) {
error_report("failed to init vhost_net for queue %d", i);
goto err;
}
if (i == 0) {
max_queues = vhost_net_get_max_queues(s->vhost_net);
if (queues > max_queues) {
error_report("you are asking more queues than supported: %d",
max_queues);
goto err;
}
}
}
return 0;
err:
vhost_user_stop(i + 1, ncs);
return -1;
}
static ssize_t vhost_user_receive(NetClientState *nc, const uint8_t *buf,
size_t size)
{
/* In case of RARP (message size is 60) notify backup to send a fake RARP.
This fake RARP will be sent by backend only for guest
without GUEST_ANNOUNCE capability.
*/
if (size == 60) {
VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
int r;
static int display_rarp_failure = 1;
char mac_addr[6];
/* extract guest mac address from the RARP message */
memcpy(mac_addr, &buf[6], 6);
r = vhost_net_notify_migration_done(s->vhost_net, mac_addr);
if ((r != 0) && (display_rarp_failure)) {
fprintf(stderr,
"Vhost user backend fails to broadcast fake RARP\n");
fflush(stderr);
display_rarp_failure = 0;
}
}
return size;
}
static void vhost_user_cleanup(NetClientState *nc)
{
VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
if (s->vhost_net) {
vhost_net_cleanup(s->vhost_net);
s->vhost_net = NULL;
}
qemu_purge_queued_packets(nc);
}
static bool vhost_user_has_vnet_hdr(NetClientState *nc)
{
assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
return true;
}
static bool vhost_user_has_ufo(NetClientState *nc)
{
assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
return true;
}
static NetClientInfo net_vhost_user_info = {
.type = NET_CLIENT_OPTIONS_KIND_VHOST_USER,
.size = sizeof(VhostUserState),
.receive = vhost_user_receive,
.cleanup = vhost_user_cleanup,
.has_vnet_hdr = vhost_user_has_vnet_hdr,
.has_ufo = vhost_user_has_ufo,
};
static void net_vhost_user_event(void *opaque, int event)
{
const char *name = opaque;
NetClientState *ncs[MAX_QUEUE_NUM];
VhostUserState *s;
Error *err = NULL;
int queues;
queues = qemu_find_net_clients_except(name, ncs,
NET_CLIENT_OPTIONS_KIND_NIC,
MAX_QUEUE_NUM);
assert(queues < MAX_QUEUE_NUM);
s = DO_UPCAST(VhostUserState, nc, ncs[0]);
trace_vhost_user_event(s->chr->label, event);
switch (event) {
case CHR_EVENT_OPENED:
if (vhost_user_start(queues, ncs) < 0) {
exit(1);
}
qmp_set_link(name, true, &err);
break;
case CHR_EVENT_CLOSED:
qmp_set_link(name, false, &err);
vhost_user_stop(queues, ncs);
break;
}
if (err) {
error_report_err(err);
}
}
static int net_vhost_user_init(NetClientState *peer, const char *device,
const char *name, CharDriverState *chr,
int queues)
{
NetClientState *nc;
VhostUserState *s;
int i;
assert(name);
assert(queues > 0);
for (i = 0; i < queues; i++) {
nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
i, chr->label);
nc->queue_index = i;
s = DO_UPCAST(VhostUserState, nc, nc);
s->chr = chr;
}
qemu_chr_add_handlers(chr, NULL, NULL, net_vhost_user_event, nc[0].name);
return 0;
}
static int net_vhost_chardev_opts(void *opaque,
const char *name, const char *value,
Error **errp)
{
VhostUserChardevProps *props = opaque;
if (strcmp(name, "backend") == 0 && strcmp(value, "socket") == 0) {
props->is_socket = true;
} else if (strcmp(name, "path") == 0) {
props->is_unix = true;
} else if (strcmp(name, "server") == 0) {
} else {
error_setg(errp,
"vhost-user does not support a chardev with option %s=%s",
name, value);
return -1;
}
return 0;
}
static CharDriverState *net_vhost_parse_chardev(
const NetdevVhostUserOptions *opts, Error **errp)
{
CharDriverState *chr = qemu_chr_find(opts->chardev);
VhostUserChardevProps props;
if (chr == NULL) {
error_setg(errp, "chardev \"%s\" not found", opts->chardev);
return NULL;
}
/* inspect chardev opts */
memset(&props, 0, sizeof(props));
if (qemu_opt_foreach(chr->opts, net_vhost_chardev_opts, &props, errp)) {
return NULL;
}
if (!props.is_socket || !props.is_unix) {
error_setg(errp, "chardev \"%s\" is not a unix socket",
opts->chardev);
return NULL;
}
qemu_chr_fe_claim_no_fail(chr);
return chr;
}
static int net_vhost_check_net(void *opaque, QemuOpts *opts, Error **errp)
{
const char *name = opaque;
const char *driver, *netdev;
const char virtio_name[] = "virtio-net-";
driver = qemu_opt_get(opts, "driver");
netdev = qemu_opt_get(opts, "netdev");
if (!driver || !netdev) {
return 0;
}
if (strcmp(netdev, name) == 0 &&
strncmp(driver, virtio_name, strlen(virtio_name)) != 0) {
error_setg(errp, "vhost-user requires frontend driver virtio-net-*");
return -1;
}
return 0;
}
int net_init_vhost_user(const NetClientOptions *opts, const char *name,
NetClientState *peer, Error **errp)
{
int queues;
const NetdevVhostUserOptions *vhost_user_opts;
CharDriverState *chr;
assert(opts->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
vhost_user_opts = opts->u.vhost_user.data;
chr = net_vhost_parse_chardev(vhost_user_opts, errp);
if (!chr) {
return -1;
}
/* verify net frontend */
if (qemu_opts_foreach(qemu_find_opts("device"), net_vhost_check_net,
(char *)name, errp)) {
return -1;
}
queues = vhost_user_opts->has_queues ? vhost_user_opts->queues : 1;
if (queues < 1 || queues > MAX_QUEUE_NUM) {
error_setg(errp,
"vhost-user number of queues must be in range [1, %d]",
MAX_QUEUE_NUM);
return -1;
}
return net_vhost_user_init(peer, "vhost_user", name, chr, queues);
}