Re: [Qemu-devel] [PATCH COLO-Frame v11 34/39] net/filter-buffer: Add default filter-buffer for each netdev

[Wen Congyang]

On 12/03/2015 11:53 AM, Hailiang Zhang wrote:
> On 2015/12/3 9:17, Wen Congyang wrote:
>> On 11/24/2015 05:25 PM, zhanghailiang wrote:
>>> We add each netdev a default filter-buffer, which will be used for COLO
>>> or Micro-checkpoint to buffer VM's packets. The name of default 
>>> filter-buffer
>>> is 'nop'.
>>> For the default filter-buffer, it will not buffer any packets in default.
>>> So it has no side effect for the netdev.
>>
>> No, filter-buffer doesn't support vhost, so if you add default filter-buffer
>> for each netdev, you can't use vhost.
>>
> 
> Have you tested it ? Did the default filter-buffer break vhost ?
> It's not supposed to break vhost, I will look into it. Thanks.

Yes, I have tested it. When I want to start a normal vm with vhost, I get
the following error messages:

qemu-system-x86_64: -netdev tap,id=hn0,queues=1,vhost=on: Vhost is not supported

Thanks
Wen Congyang
> 
>> Thanks
>> Wen Congyang
>>
>>>
>>> Signed-off-by: zhanghailiang <address@hidden>
>>> Cc: Jason Wang <address@hidden>
>>> Cc: Yang Hongyang <address@hidden>
>>> ---
>>> v11:
>>> - New patch
>>> ---
>>>   include/net/filter.h |  3 +++
>>>   net/filter-buffer.c  | 74 
>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>   net/net.c            |  8 ++++++
>>>   3 files changed, 85 insertions(+)
>>>
>>> diff --git a/include/net/filter.h b/include/net/filter.h
>>> index 2deda36..01a7e90 100644
>>> --- a/include/net/filter.h
>>> +++ b/include/net/filter.h
>>> @@ -74,4 +74,7 @@ ssize_t qemu_netfilter_pass_to_next(NetClientState 
>>> *sender,
>>>                                       int iovcnt,
>>>                                       void *opaque);
>>>
>>> +void netdev_add_default_filter_buffer(const char *netdev_id,
>>> +                                      NetFilterDirection direction,
>>> +                                      Error **errp);
>>>   #endif /* QEMU_NET_FILTER_H */
>>> diff --git a/net/filter-buffer.c b/net/filter-buffer.c
>>> index 57be149..195af68 100644
>>> --- a/net/filter-buffer.c
>>> +++ b/net/filter-buffer.c
>>> @@ -14,6 +14,12 @@
>>>   #include "qapi/qmp/qerror.h"
>>>   #include "qapi-visit.h"
>>>   #include "qom/object.h"
>>> +#include "net/net.h"
>>> +#include "qapi/qmp/qdict.h"
>>> +#include "qapi/qmp-output-visitor.h"
>>> +#include "qapi/qmp-input-visitor.h"
>>> +#include "monitor/monitor.h"
>>> +#include "qmp-commands.h"
>>>
>>>   #define TYPE_FILTER_BUFFER "filter-buffer"
>>>
>>> @@ -26,6 +32,8 @@ typedef struct FilterBufferState {
>>>       NetQueue *incoming_queue;
>>>       uint32_t interval;
>>>       QEMUTimer release_timer;
>>> +    bool is_default;
>>> +    bool enable_buffer;
>>>   } FilterBufferState;
>>>
>>>   static void filter_buffer_flush(NetFilterState *nf)
>>> @@ -65,6 +73,10 @@ static ssize_t filter_buffer_receive_iov(NetFilterState 
>>> *nf,
>>>   {
>>>       FilterBufferState *s = FILTER_BUFFER(nf);
>>>
>>> +    /* Don't buffer any packets if the filter is not enabled */
>>> +    if (!s->enable_buffer) {
>>> +        return 0;
>>> +    }
>>>       /*
>>>        * We return size when buffer a packet, the sender will take it as
>>>        * a already sent packet, so sent_cb should not be called later.
>>> @@ -102,6 +114,7 @@ static void filter_buffer_cleanup(NetFilterState *nf)
>>>   static void filter_buffer_setup(NetFilterState *nf, Error **errp)
>>>   {
>>>       FilterBufferState *s = FILTER_BUFFER(nf);
>>> +    char *path = object_get_canonical_path_component(OBJECT(nf));
>>>
>>>       /*
>>>        * We may want to accept zero interval when VM FT solutions like MC
>>> @@ -114,6 +127,7 @@ static void filter_buffer_setup(NetFilterState *nf, 
>>> Error **errp)
>>>       }
>>>
>>>       s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, 
>>> nf);
>>> +    s->is_default = !strcmp(path, "nop");
>>>       if (s->interval) {
>>>           timer_init_us(&s->release_timer, QEMU_CLOCK_VIRTUAL,
>>>                         filter_buffer_release_timer, nf);
>>> @@ -163,6 +177,66 @@ out:
>>>       error_propagate(errp, local_err);
>>>   }
>>>
>>> +/*
>>> +* This will be used by COLO or MC FT, for which they will need
>>> +* to buffer the packets of VM's net devices, Here we add a default
>>> +* buffer filter for each netdev. The name of default buffer filter is
>>> +* 'nop'
>>> +*/
>>> +void netdev_add_default_filter_buffer(const char *netdev_id,
>>> +                                      NetFilterDirection direction,
>>> +                                      Error **errp)
>>> +{
>>> +    QmpOutputVisitor *qov;
>>> +    QmpInputVisitor *qiv;
>>> +    Visitor *ov, *iv;
>>> +    QObject *obj = NULL;
>>> +    QDict *qdict;
>>> +    void *dummy = NULL;
>>> +    const char *id = "nop";
>>> +    char *queue = g_strdup(NetFilterDirection_lookup[direction]);
>>> +    NetClientState *nc = qemu_find_netdev(netdev_id);
>>> +    Error *err = NULL;
>>> +
>>> +    /* FIXME: Not support multiple queues */
>>> +    if (!nc || nc->queue_index > 1) {
>>> +        return;
>>> +    }
>>> +    qov = qmp_output_visitor_new();
>>> +    ov = qmp_output_get_visitor(qov);
>>> +    visit_start_struct(ov,  &dummy, NULL, NULL, 0, &err);
>>> +    if (err) {
>>> +        goto out;
>>> +    }
>>> +    visit_type_str(ov, &nc->name, "netdev", &err);
>>> +    if (err) {
>>> +        goto out;
>>> +    }
>>> +    visit_type_str(ov, &queue, "queue", &err);
>>> +    if (err) {
>>> +        goto out;
>>> +    }
>>> +    visit_end_struct(ov, &err);
>>> +    if (err) {
>>> +        goto out;
>>> +    }
>>> +    obj = qmp_output_get_qobject(qov);
>>> +    g_assert(obj != NULL);
>>> +    qdict = qobject_to_qdict(obj);
>>> +    qmp_output_visitor_cleanup(qov);
>>> +
>>> +    qiv = qmp_input_visitor_new(obj);
>>> +    iv = qmp_input_get_visitor(qiv);
>>> +    object_add(TYPE_FILTER_BUFFER, id, qdict, iv, &err);
>>> +    qmp_input_visitor_cleanup(qiv);
>>> +    qobject_decref(obj);
>>> +out:
>>> +    g_free(queue);
>>> +    if (err) {
>>> +        error_propagate(errp, err);
>>> +    }
>>> +}
>>> +
>>>   static void filter_buffer_init(Object *obj)
>>>   {
>>>       object_property_add(obj, "interval", "int",
>>> diff --git a/net/net.c b/net/net.c
>>> index ade6051..b36d49f 100644
>>> --- a/net/net.c
>>> +++ b/net/net.c
>>> @@ -1028,6 +1028,14 @@ static int net_client_init1(const void *object, int 
>>> is_netdev, Error **errp)
>>>           }
>>>           return -1;
>>>       }
>>> +
>>> +    if (is_netdev) {
>>> +        const Netdev *netdev = object;
>>> +
>>> +        netdev_add_default_filter_buffer(netdev->id,
>>> +                                         NET_FILTER_DIRECTION_RX,
>>> +                                         errp);
>>> +    }
>>>       return 0;
>>>   }
>>>
>>>
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