Re: [Qemu-devel] [PATCH v7 11/13] Add new vhost-user netdev backend

[Antonios Motakis]

On Mon, Feb 10, 2014 at 9:42 AM, Michael S. Tsirkin <address@hidden> wrote:
> On Fri, Jan 31, 2014 at 06:34:40PM +0100, Antonios Motakis wrote:
>> Add a new QEMU netdev backend that is intended to invoke vhost_net with the
>> vhost-user backend.
>>
>> At runtime the netdev will detect if the vhost backend is up or down. Upon
>> disconnection it will set link_down accordingly and notify virtio-net. The
>> virtio-net interface goes down.
>>
>> Signed-off-by: Antonios Motakis <address@hidden>
>> Signed-off-by: Nikolay Nikolaev <address@hidden>
>
> What happens if users try to configure e.g. e1000 with this
> netdev backend?
> I would expect some code in the backend checking that
> frontend is virtio, but I don't see such.

Good point, we are looking into it. Thanks.

>
>> ---
>>  include/net/vhost-user.h |  17 +++++++
>>  net/Makefile.objs        |   2 +-
>>  net/clients.h            |   3 ++
>>  net/vhost-user.c         | 130 
>> +++++++++++++++++++++++++++++++++++++++++++++++
>>  4 files changed, 151 insertions(+), 1 deletion(-)
>>  create mode 100644 include/net/vhost-user.h
>>  create mode 100644 net/vhost-user.c
>>
>> diff --git a/include/net/vhost-user.h b/include/net/vhost-user.h
>> new file mode 100644
>> index 0000000..85109f6
>> --- /dev/null
>> +++ b/include/net/vhost-user.h
>> @@ -0,0 +1,17 @@
>> +/*
>> + * vhost-user.h
>> + *
>> + * 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.
>> + *
>> + */
>> +
>> +#ifndef VHOST_USER_H_
>> +#define VHOST_USER_H_
>> +
>> +struct vhost_net;
>> +struct vhost_net *vhost_user_get_vhost_net(NetClientState *nc);
>> +
>> +#endif /* VHOST_USER_H_ */
>> diff --git a/net/Makefile.objs b/net/Makefile.objs
>> index c25fe69..301f6b6 100644
>> --- a/net/Makefile.objs
>> +++ b/net/Makefile.objs
>> @@ -2,7 +2,7 @@ common-obj-y = net.o queue.o checksum.o util.o hub.o
>>  common-obj-y += socket.o
>>  common-obj-y += dump.o
>>  common-obj-y += eth.o
>> -common-obj-$(CONFIG_POSIX) += tap.o
>> +common-obj-$(CONFIG_POSIX) += tap.o vhost-user.o
>>  common-obj-$(CONFIG_LINUX) += tap-linux.o
>>  common-obj-$(CONFIG_WIN32) += tap-win32.o
>>  common-obj-$(CONFIG_BSD) += tap-bsd.o
>> diff --git a/net/clients.h b/net/clients.h
>> index 7322ff5..7f3d4ae 100644
>> --- a/net/clients.h
>> +++ b/net/clients.h
>> @@ -57,4 +57,7 @@ int net_init_netmap(const NetClientOptions *opts, const 
>> char *name,
>>                      NetClientState *peer);
>>  #endif
>>
>> +int net_init_vhost_user(const NetClientOptions *opts, const char *name,
>> +                        NetClientState *peer);
>> +
>>  #endif /* QEMU_NET_CLIENTS_H */
>> diff --git a/net/vhost-user.c b/net/vhost-user.c
>> new file mode 100644
>> index 0000000..b25722c
>> --- /dev/null
>> +++ b/net/vhost-user.c
>> @@ -0,0 +1,130 @@
>> +/*
>> + * 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 "clients.h"
>> +#include "net/vhost_net.h"
>> +#include "net/vhost-user.h"
>> +#include "sysemu/char.h"
>> +#include "qemu/error-report.h"
>> +
>> +typedef struct VhostUserState {
>> +    NetClientState nc;
>> +    CharDriverState *chr;
>> +    VHostNetState *vhost_net;
>> +} VhostUserState;
>> +
>> +VHostNetState *vhost_user_get_vhost_net(NetClientState *nc)
>> +{
>> +    VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
>> +    return s->vhost_net;
>> +}
>> +
>> +static int vhost_user_running(VhostUserState *s)
>> +{
>> +    return (s->vhost_net) ? 1 : 0;
>> +}
>> +
>> +static int vhost_user_start(VhostUserState *s)
>> +{
>> +    VhostNetOptions options;
>> +
>> +    if (vhost_user_running(s)) {
>> +        return 0;
>> +    }
>> +
>> +    options.backend_type = VHOST_BACKEND_TYPE_USER;
>> +    options.net_backend = &s->nc;
>> +    options.opaque = s->chr;
>> +    options.force = 1;
>> +
>> +    s->vhost_net = vhost_net_init(&options);
>> +
>> +    return vhost_user_running(s) ? 0 : -1;
>> +}
>> +
>> +static void vhost_user_stop(VhostUserState *s)
>> +{
>> +    if (vhost_user_running(s)) {
>> +        vhost_net_cleanup(s->vhost_net);
>> +    }
>> +
>> +    s->vhost_net = 0;
>> +}
>> +
>> +static void vhost_user_cleanup(NetClientState *nc)
>> +{
>> +    VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
>> +
>> +    vhost_user_stop(s);
>> +    qemu_purge_queued_packets(nc);
>> +}
>> +
>> +static NetClientInfo net_vhost_user_info = {
>> +        .type = 0,
>> +        .size = sizeof(VhostUserState),
>> +        .cleanup = vhost_user_cleanup,
>> +};
>> +
>> +static void net_vhost_user_event(void *opaque, int event)
>> +{
>> +    VhostUserState *s = opaque;
>> +
>> +    switch (event) {
>> +    case CHR_EVENT_OPENED:
>> +        vhost_user_start(s);
>> +        break;
>> +    case CHR_EVENT_CLOSED:
>> +        s->nc.link_down = 1;
>> +
>> +        if (s->nc.peer) {
>> +            s->nc.peer->link_down = 1;
>> +        }
>> +
>> +        if (s->nc.info->link_status_changed) {
>> +            s->nc.info->link_status_changed(&s->nc);
>> +        }
>> +
>> +        if (s->nc.peer && s->nc.peer->info->link_status_changed) {
>> +            s->nc.peer->info->link_status_changed(s->nc.peer);
>> +        }
>> +
>> +        vhost_user_stop(s);
>> +        error_report("chardev \"%s\" went down\n", s->chr->label);
>> +        break;
>> +    }
>> +}
>> +
>> +static int net_vhost_user_init(NetClientState *peer, const char *device,
>> +                               const char *name, CharDriverState *chr)
>> +{
>> +    NetClientState *nc;
>> +    VhostUserState *s;
>> +
>> +    nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
>> +
>> +    snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user to %s",
>> +             chr->label);
>> +
>> +    s = DO_UPCAST(VhostUserState, nc, nc);
>> +
>> +    /* We don't provide a receive callback */
>> +    s->nc.receive_disabled = 1;
>> +    s->chr = chr;
>> +
>> +    qemu_chr_add_handlers(s->chr, NULL, NULL, net_vhost_user_event, s);
>> +
>> +    return 0;
>> +}
>> +
>> +int net_init_vhost_user(const NetClientOptions *opts, const char *name,
>> +                   NetClientState *peer)
>> +{
>> +    return net_vhost_user_init(peer, "vhost_user", 0, 0);
>> +}
>> --
>> 1.8.3.2
>>



-- 
Antonios Motakis
Virtual Open Systems