Re: [Qemu-devel] [PATCH V12 02/10] colo-compare: introduce colo compare initialization

[Zhang Chen <zhangchen.fnst@cn.fujitsu.com>]

On 08/31/2016 05:20 PM, Jason Wang wrote:
>
>
> On 2016年08月31日 17:03, Zhang Chen wrote:
>>
>>
>> On 08/31/2016 03:53 PM, Jason Wang wrote:
>>>
>>>
>>> On 2016年08月17日 16:10, Zhang Chen wrote:
>>>> This a COLO net ascii figure:
>>>>
>>>>   Primary qemu Secondary qemu
>>>> +--------------------------------------------------------------+ 
>>>> +----------------------------------------------------------------+
>>>> | +----------------------------------------------------------+ 
>>>> |       | 
>>>> +-----------------------------------------------------------+ |
>>>> | | | |       | | | |
>>>> | |                        guest | |       |  | 
>>>> guest                              | |
>>>> | | | |       | | | |
>>>> | +-------^--------------------------+-----------------------+ 
>>>> |       | 
>>>> +---------------------+--------+----------------------------+ |
>>>> |         |                          | | |                        ^ 
>>>> |                              |
>>>> |         |                          | | |                        | 
>>>> |                              |
>>>> |         | 
>>>> +------------------------------------------------------+ 
>>>> |                        |        | |
>>>> |netfilter|  |                       | |    |  | 
>>>> netfilter            | |                              |
>>>> | +----------+ +----------------------------+ |    |  | 
>>>> +-----------------------------------------------------------+ |
>>>> | |       |  |                       |      |        out | |  |  
>>>> |                     |        |  filter excute order       | |
>>>> | |       |  |          +-----------------------------+ | | |  
>>>> |                     |        | +------------------->      | |
>>>> | |       |  |          |            |      |         | | | |  
>>>> |                     |        | TCP | |
>>>> | | +-----+--+-+  +-----v----+ +-----v----+ |pri +----+----+sec|    
>>>> |  |  | +------------+ +---+----+---v+rewriter++  +------------+ | |
>>>> | | |          |  |          | |          | |in  | |in |    |  |  | 
>>>> |            |  |        |              | |            | | |
>>>> | | |  filter  |  |  filter  | |  filter  +------>  colo <------+ 
>>>> +-------->  filter   +--> adjust | adjust     +-->   filter   | | |
>>>> | | |  mirror  |  |redirector| |redirector| |    | compare | |  
>>>> |    |  | | redirector |  | ack    |   seq        |  | redirector | 
>>>> | |
>>>> | | |          |  |          | |          | |    |         | |  
>>>> |    |  | |            |  |        |              | |            | | |
>>>> | | +----^-----+  +----+-----+ +----------+ |    +---------+ |  
>>>> |    |  | +------------+  +--------+--------------+ +---+--------+ | |
>>>> | |      |   tx        |   rx           rx  | |  |    | 
>>>> |            tx                        all       | rx      | |
>>>> | |      |             |                    | |  |    | 
>>>> +-----------------------------------------------------------+ |
>>>> | |      |             +--------------+     | |  |    | |            |
>>>> | |      |   filter excute order      |     | |  |    | |            |
>>>> | |      |  +---------------->        | | | 
>>>> +--------------------------------------------------------+ |
>>>> | +-----------------------------------------+ | | |
>>>> |        |                            | | | |
>>>> +--------------------------------------------------------------+ 
>>>> +----------------------------------------------------------------+
>>>>           |guest receive               | guest send
>>>>           |                            |
>>>> +--------+----------------------------v------------------------+
>>>> | |                          NOTE: filter direction is rx/tx/all
>>>> |                         tap | rx:receive packets sent to the netdev
>>>> | |                          tx:receive packets sent by the netdev
>>>> +--------------------------------------------------------------+
>>>
>>> It's better to add a doc under docs to explain this configuration in 
>>> detail on top of this series.
>>>
>>
>> As you say, Am I add /docs/colo-proxy.txt to explain it or add this 
>> in hailiang's COLO-FT.txt after merge?

Can you give me a way for doc?


>>
>>>> In COLO-compare, we do packet comparing job.
>>>> Packets coming from the primary char indev will be sent to outdev.
>>>> Packets coming from the secondary char dev will be dropped after 
>>>> comparing.
>>>> colo-comapre need two input chardev and one output chardev:
>>>> primary_in=chardev1-id (source: primary send packet)
>>>> secondary_in=chardev2-id (source: secondary send packet)
>>>> outdev=chardev3-id
>>>>
>>>> usage:
>>>>
>>>> primary:
>>>> -netdev 
>>>> tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
>>>> -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
>>>> -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait
>>>> -chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait
>>>> -chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait
>>>> -chardev socket,id=compare0-0,host=3.3.3.3,port=9001
>>>> -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait
>>>> -chardev socket,id=compare_out0,host=3.3.3.3,port=9005
>>>> -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
>>>> -object 
>>>> filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
>>>> -object 
>>>> filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
>>>> -object 
>>>> colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0
>>>>
>>>> secondary:
>>>> -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down 
>>>> script=/etc/qemu-ifdown
>>>> -device e1000,netdev=hn0,mac=52:a4:00:12:78:66
>>>> -chardev socket,id=red0,host=3.3.3.3,port=9003
>>>> -chardev socket,id=red1,host=3.3.3.3,port=9004
>>>> -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
>>>> -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
>>>>
>>>> Signed-off-by: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
>>>> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
>>>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>>>> ---
>>>>   net/Makefile.objs  |   1 +
>>>>   net/colo-compare.c | 284 
>>>> +++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>>   qemu-options.hx    |  39 ++++++++
>>>>   vl.c               |   3 +-
>>>>   4 files changed, 326 insertions(+), 1 deletion(-)
>>>>   create mode 100644 net/colo-compare.c
>>>>
>>>> diff --git a/net/Makefile.objs b/net/Makefile.objs
>>>> index b7c22fd..ba92f73 100644
>>>> --- a/net/Makefile.objs
>>>> +++ b/net/Makefile.objs
>>>> @@ -16,3 +16,4 @@ common-obj-$(CONFIG_NETMAP) += netmap.o
>>>>   common-obj-y += filter.o
>>>>   common-obj-y += filter-buffer.o
>>>>   common-obj-y += filter-mirror.o
>>>> +common-obj-y += colo-compare.o
>>>> diff --git a/net/colo-compare.c b/net/colo-compare.c
>>>> new file mode 100644
>>>> index 0000000..cdc3e0e
>>>> --- /dev/null
>>>> +++ b/net/colo-compare.c
>>>> @@ -0,0 +1,284 @@
>>>> +/*
>>>> + * COarse-grain LOck-stepping Virtual Machines for Non-stop 
>>>> Service (COLO)
>>>> + * (a.k.a. Fault Tolerance or Continuous Replication)
>>>> + *
>>>> + * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
>>>> + * Copyright (c) 2016 FUJITSU LIMITED
>>>> + * Copyright (c) 2016 Intel Corporation
>>>> + *
>>>> + * Author: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
>>>> + *
>>>> + * 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 "qemu/error-report.h"
>>>> +#include "qemu-common.h"
>>>> +#include "qapi/qmp/qerror.h"
>>>> +#include "qapi/error.h"
>>>> +#include "net/net.h"
>>>> +#include "net/vhost_net.h"
>>>
>>> Looks unnecessary.
>>
>> I will remove it.
>>
>>>
>>>> +#include "qom/object_interfaces.h"
>>>> +#include "qemu/iov.h"
>>>> +#include "qom/object.h"
>>>> +#include "qemu/typedefs.h"
>>>> +#include "net/queue.h"
>>>> +#include "sysemu/char.h"
>>>> +#include "qemu/sockets.h"
>>>> +#include "qapi-visit.h"
>>>> +
>>>> +#define TYPE_COLO_COMPARE "colo-compare"
>>>> +#define COLO_COMPARE(obj) \
>>>> +    OBJECT_CHECK(CompareState, (obj), TYPE_COLO_COMPARE)
>>>> +
>>>> +#define COMPARE_READ_LEN_MAX NET_BUFSIZE
>>>> +
>>>> +typedef struct CompareState {
>>>> +    Object parent;
>>>> +
>>>> +    char *pri_indev;
>>>> +    char *sec_indev;
>>>> +    char *outdev;
>>>> +    CharDriverState *chr_pri_in;
>>>> +    CharDriverState *chr_sec_in;
>>>> +    CharDriverState *chr_out;
>>>> +    QTAILQ_ENTRY(CompareState) next;
>>>
>>> This looks not used in this series but in commit "colo-compare and 
>>> filter-rewriter work with colo-frame". We'd better delay the 
>>> introducing to that patch.
>>
>> OK~ I got your point.
>>
>>>
>>>> +    SocketReadState pri_rs;
>>>> +    SocketReadState sec_rs;
>>>> +} CompareState;
>>>> +
>>>> +typedef struct CompareClass {
>>>> +    ObjectClass parent_class;
>>>> +} CompareClass;
>>>> +
>>>> +typedef struct CompareChardevProps {
>>>> +    bool is_socket;
>>>> +    bool is_unix;
>>>> +} CompareChardevProps;
>>>> +
>>>> +static char *compare_get_pri_indev(Object *obj, Error **errp)
>>>> +{
>>>> +    CompareState *s = COLO_COMPARE(obj);
>>>> +
>>>> +    return g_strdup(s->pri_indev);
>>>> +}
>>>> +
>>>> +static void compare_set_pri_indev(Object *obj, const char *value, 
>>>> Error **errp)
>>>> +{
>>>> +    CompareState *s = COLO_COMPARE(obj);
>>>> +
>>>> +    g_free(s->pri_indev);
>>>> +    s->pri_indev = g_strdup(value);
>>>> +}
>>>> +
>>>> +static char *compare_get_sec_indev(Object *obj, Error **errp)
>>>> +{
>>>> +    CompareState *s = COLO_COMPARE(obj);
>>>> +
>>>> +    return g_strdup(s->sec_indev);
>>>> +}
>>>> +
>>>> +static void compare_set_sec_indev(Object *obj, const char *value, 
>>>> Error **errp)
>>>> +{
>>>> +    CompareState *s = COLO_COMPARE(obj);
>>>> +
>>>> +    g_free(s->sec_indev);
>>>> +    s->sec_indev = g_strdup(value);
>>>> +}
>>>> +
>>>> +static char *compare_get_outdev(Object *obj, Error **errp)
>>>> +{
>>>> +    CompareState *s = COLO_COMPARE(obj);
>>>> +
>>>> +    return g_strdup(s->outdev);
>>>> +}
>>>> +
>>>> +static void compare_set_outdev(Object *obj, const char *value, 
>>>> Error **errp)
>>>> +{
>>>> +    CompareState *s = COLO_COMPARE(obj);
>>>> +
>>>> +    g_free(s->outdev);
>>>> +    s->outdev = g_strdup(value);
>>>> +}
>>>> +
>>>> +static void compare_pri_rs_finalize(SocketReadState *pri_rs)
>>>> +{
>>>> +    /* if packet_enqueue pri pkt failed we will send unsupported 
>>>> packet */
>>>> +}
>>>> +
>>>> +static void compare_sec_rs_finalize(SocketReadState *sec_rs)
>>>> +{
>>>> +    /* if packet_enqueue sec pkt failed we will notify trace */
>>>> +}
>>>> +
>>>> +static int compare_chardev_opts(void *opaque,
>>>> +                                const char *name, const char *value,
>>>> +                                Error **errp)
>>>> +{
>>>> +    CompareChardevProps *props = opaque;
>>>> +
>>>> +    if (strcmp(name, "backend") == 0 && strcmp(value, "socket") == 
>>>> 0) {
>>>> +        props->is_socket = true;
>>>> +    } else if (strcmp(name, "host") == 0) {
>>>
>>> Typo? net_vhost_chardev_opts() did:
>>>
>>>     } else if (strcmp(name, "path") == 0) {
>>>         props->is_unix = true;
>>>     }
>>>
>>>
>>
>> No, In colo-compare we use chardev like this:
>>
>> -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait
>>
>> If we only use "path" here will trigger a error.
>> Should I add anthor "path" here?
>
> If I understand the code correctly, "is_unix" means "is unix domain 
> socket"? If yes, according to the help:
>
> -chardev 
> socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]
> [,server][,nowait][,telnet][,reconnect=seconds][,mux=on|off]
>          [,logfile=PATH][,logappend=on|off][,tls-creds=ID] (tcp)
> -chardev 
> socket,id=id,path=path[,server][,nowait][,telnet][,reconnect=seconds]
>          [,mux=on|off][,logfile=PATH][,logappend=on|off] (unix)
>
> "host" will not be used for UNIX domain socket.
>
> And if UNIX domain socket is not supported, there's probably no need 
> to differentiate it from other types.

OK, I will remove the "is_unix" in next version.


>
>>
>>
>>>
>>>> +        props->is_unix = true;
>>>> +    } else if (strcmp(name, "port") == 0) {
>>>> +    } else if (strcmp(name, "server") == 0) {
>>>> +    } else if (strcmp(name, "wait") == 0) {
>>>> +    } else {
>>>> +        error_setg(errp,
>>>> +                   "COLO-compare does not support a chardev with 
>>>> option %s=%s",
>>>> +                   name, value);
>>>> +        return -1;
>>>> +    }
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +/*
>>>> + * called from the main thread on the primary
>>>> + * to setup colo-compare.
>>>> + */
>>>> +static void colo_compare_complete(UserCreatable *uc, Error **errp)
>>>> +{
>>>> +    CompareState *s = COLO_COMPARE(uc);
>>>> +    CompareChardevProps props;
>>>> +
>>>> +    if (!s->pri_indev || !s->sec_indev || !s->outdev) {
>>>> +        error_setg(errp, "colo compare needs 'primary_in' ,"
>>>> +                   "'secondary_in','outdev' property set");
>>>> +        return;
>>>> +    } else if (!strcmp(s->pri_indev, s->outdev) ||
>>>> +               !strcmp(s->sec_indev, s->outdev) ||
>>>> +               !strcmp(s->pri_indev, s->sec_indev)) {
>>>> +        error_setg(errp, "'indev' and 'outdev' could not be same "
>>>> +                   "for compare module");
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    s->chr_pri_in = qemu_chr_find(s->pri_indev);
>>>> +    if (s->chr_pri_in == NULL) {
>>>> +        error_setg(errp, "Primary IN Device '%s' not found",
>>>> +                   s->pri_indev);
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    /* inspect chardev opts */
>>>> +    memset(&props, 0, sizeof(props));
>>>> +    if (qemu_opt_foreach(s->chr_pri_in->opts, 
>>>> compare_chardev_opts, &props, errp)) {
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    if (!props.is_socket || !props.is_unix) {
>>>> +        error_setg(errp, "chardev \"%s\" is not a unix socket",
>>>> +                   s->pri_indev);
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    s->chr_sec_in = qemu_chr_find(s->sec_indev);
>>>> +    if (s->chr_sec_in == NULL) {
>>>> +        error_setg(errp, "Secondary IN Device '%s' not found",
>>>> +                   s->sec_indev);
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    memset(&props, 0, sizeof(props));
>>>> +    if (qemu_opt_foreach(s->chr_sec_in->opts, 
>>>> compare_chardev_opts, &props, errp)) {
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    if (!props.is_socket || !props.is_unix) {
>>>> +        error_setg(errp, "chardev \"%s\" is not a unix socket",
>>>> +                   s->sec_indev);
>>>
>>> I believe tcp socket is also supported?
>>
>> If I understand correctly, "tcp socket" in here is the "-chardev 
>> socket".
>> I will rename "unix socket" to "tcp socket".
>>
>>>
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    s->chr_out = qemu_chr_find(s->outdev);
>>>> +    if (s->chr_out == NULL) {
>>>> +        error_setg(errp, "OUT Device '%s' not found", s->outdev);
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    memset(&props, 0, sizeof(props));
>>>> +    if (qemu_opt_foreach(s->chr_out->opts, compare_chardev_opts, 
>>>> &props, errp)) {
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    if (!props.is_socket || !props.is_unix) {
>>>> +        error_setg(errp, "chardev \"%s\" is not a unix socket",
>>>> +                   s->outdev);
>>>
>>> Ditto, and there's code duplication, please introduce a helper to do 
>>> above.
>>
>> I don't understand what the "helper"?
>> In here we check each chardev, will I change to "goto error;" ?
>
> A helper to avoid the code duplication for socket type inspection for 
> pri_in,scr_in and chr_out.

I got it~~
I will add it in next version.


>
>>
>>>
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    qemu_chr_fe_claim_no_fail(s->chr_pri_in);
>>>> +
>>>> +    qemu_chr_fe_claim_no_fail(s->chr_sec_in);
>>>> +
>>>> +    qemu_chr_fe_claim_no_fail(s->chr_out);
>>>> +
>>>> +    net_socket_rs_init(&s->pri_rs, compare_pri_rs_finalize);
>>>> +    net_socket_rs_init(&s->sec_rs, compare_sec_rs_finalize);
>>>> +
>>>> +    return;
>>>> +}
>>>> +
>>>> +static void colo_compare_class_init(ObjectClass *oc, void *data)
>>>> +{
>>>> +    UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
>>>> +
>>>> +    ucc->complete = colo_compare_complete;
>>>> +}
>>>> +
>>>> +static void colo_compare_init(Object *obj)
>>>> +{
>>>> +    object_property_add_str(obj, "primary_in",
>>>> +                            compare_get_pri_indev, 
>>>> compare_set_pri_indev,
>>>> +                            NULL);
>>>> +    object_property_add_str(obj, "secondary_in",
>>>> +                            compare_get_sec_indev, 
>>>> compare_set_sec_indev,
>>>> +                            NULL);
>>>> +    object_property_add_str(obj, "outdev",
>>>> +                            compare_get_outdev, compare_set_outdev,
>>>> +                            NULL);
>>>> +}
>>>> +
>>>> +static void colo_compare_finalize(Object *obj)
>>>> +{
>>>> +    CompareState *s = COLO_COMPARE(obj);
>>>> +
>>>> +    if (s->chr_pri_in) {
>>>> +        qemu_chr_add_handlers(s->chr_pri_in, NULL, NULL, NULL, NULL);
>>>> +        qemu_chr_fe_release(s->chr_pri_in);
>>>> +    }
>>>> +    if (s->chr_sec_in) {
>>>> +        qemu_chr_add_handlers(s->chr_sec_in, NULL, NULL, NULL, NULL);
>>>> +        qemu_chr_fe_release(s->chr_sec_in);
>>>> +    }
>>>> +    if (s->chr_out) {
>>>> +        qemu_chr_fe_release(s->chr_out);
>>>> +    }
>>>> +
>>>> +    g_free(s->pri_indev);
>>>> +    g_free(s->sec_indev);
>>>> +    g_free(s->outdev);
>>>> +}
>>>> +
>>>> +static const TypeInfo colo_compare_info = {
>>>> +    .name = TYPE_COLO_COMPARE,
>>>> +    .parent = TYPE_OBJECT,
>>>> +    .instance_size = sizeof(CompareState),
>>>> +    .instance_init = colo_compare_init,
>>>> +    .instance_finalize = colo_compare_finalize,
>>>> +    .class_size = sizeof(CompareClass),
>>>> +    .class_init = colo_compare_class_init,
>>>> +    .interfaces = (InterfaceInfo[]) {
>>>> +        { TYPE_USER_CREATABLE },
>>>> +        { }
>>>> +    }
>>>> +};
>>>> +
>>>> +static void register_types(void)
>>>> +{
>>>> +    type_register_static(&colo_compare_info);
>>>> +}
>>>> +
>>>> +type_init(register_types);
>>>> diff --git a/qemu-options.hx b/qemu-options.hx
>>>> index 587de8f..33d5d0b 100644
>>>> --- a/qemu-options.hx
>>>> +++ b/qemu-options.hx
>>>> @@ -3866,6 +3866,45 @@ Dump the network traffic on netdev @var{dev} 
>>>> to the file specified by
>>>>   The file format is libpcap, so it can be analyzed with tools such 
>>>> as tcpdump
>>>>   or Wireshark.
>>>>   +@item -object 
>>>> colo-compare,id=@var{id},primary_in=@var{chardevid},secondary_in=@var{chardevid},
>>>> +outdev=@var{chardevid}
>>>> +
>>>> +Colo-compare gets packet from primary_in@var{chardevid} and 
>>>> secondary_in@var{chardevid}, than compare primary packet with
>>>> +secondary packet. If the packet same, we will output primary
>>>
>>> s/If the packet same/If the packets are same/.
>>
>> OK.
>>
>>>
>>>> +packet to outdev@var{chardevid}, else we will notify colo-frame
>>>> +do checkpoint and send primary packet to outdev@var{chardevid}.
>>>> +
>>>> +we can use it with the help of filter-mirror and filter-redirector.
>>>
>>> s/we/We/ and looks like colo compare must be used with the help of 
>>> mirror and redirector?
>>
>> Currently yes.
>
> Then please change the doc here.

s/We can use it/We must use it.

Thanks
Zhang Chen

>
> Thanks
>
>>
>>>
>>>> +
>>>> +@example
>>>> +
>>>> +primary:
>>>> +-netdev 
>>>> tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown
>>>> +-device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66
>>>> +-chardev socket,id=mirror0,host=3.3.3.3,port=9003,server,nowait
>>>> +-chardev socket,id=compare1,host=3.3.3.3,port=9004,server,nowait
>>>> +-chardev socket,id=compare0,host=3.3.3.3,port=9001,server,nowait
>>>> +-chardev socket,id=compare0-0,host=3.3.3.3,port=9001
>>>> +-chardev socket,id=compare_out,host=3.3.3.3,port=9005,server,nowait
>>>> +-chardev socket,id=compare_out0,host=3.3.3.3,port=9005
>>>> +-object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0
>>>> +-object 
>>>> filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out
>>>> +-object 
>>>> filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0
>>>> +-object 
>>>> colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0
>>>> +
>>>> +secondary:
>>>> +-netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down 
>>>> script=/etc/qemu-ifdown
>>>> +-device e1000,netdev=hn0,mac=52:a4:00:12:78:66
>>>> +-chardev socket,id=red0,host=3.3.3.3,port=9003
>>>> +-chardev socket,id=red1,host=3.3.3.3,port=9004
>>>> +-object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
>>>> +-object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
>>>> +
>>>> +@end example
>>>> +
>>>> +If you want to know the detail of above command line, you can read
>>>> +the colo-compare git log.
>>>> +
>>>>   @item -object 
>>>> secret,id=@var{id},data=@var{string},format=@var{raw|base64}[,keyid=@var{secretid},iv=@var{string}]
>>>>   @item -object 
>>>> secret,id=@var{id},file=@var{filename},format=@var{raw|base64}[,keyid=@var{secretid},iv=@var{string}]
>>>>   diff --git a/vl.c b/vl.c
>>>> index cbe51ac..c6b9a6f 100644
>>>> --- a/vl.c
>>>> +++ b/vl.c
>>>> @@ -2865,7 +2865,8 @@ static bool object_create_initial(const char 
>>>> *type)
>>>>       if (g_str_equal(type, "filter-buffer") ||
>>>>           g_str_equal(type, "filter-dump") ||
>>>>           g_str_equal(type, "filter-mirror") ||
>>>> -        g_str_equal(type, "filter-redirector")) {
>>>> +        g_str_equal(type, "filter-redirector") ||
>>>> +        g_str_equal(type, "colo-compare")) {
>>>>           return false;
>>>>       }
>>>
>>>
>>>
>>> .
>>>
>>
>
>
>
> .
>

-- 
Thanks
zhangchen