Patchwork [2/4] migration-tcp: threaded tcp incoming migration.

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Submitter Yoshiaki Tamura
Date June 1, 2010, 3:40 p.m.
Message ID <1275406821-30024-3-git-send-email-tamura.yoshiaki@lab.ntt.co.jp>
Download mbox | patch
Permalink /patch/54228/
State New
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Comments

Yoshiaki Tamura - June 1, 2010, 3:40 p.m.
Create a thread to handle tcp incoming migration when CONFIG_IOTHREAD
is enabled.  Spawned thread writes it's return status to th_fds[1]
before exit, and main thread joins and reads it.  In
tcp_start_incoming_migration(), allocate FdMigrationState and return
MigrationState to let migration to print incoming migration info.

Signed-off-by: Yoshiaki Tamura <tamura.yoshiaki@lab.ntt.co.jp>
---
 migration-tcp.c |   86 ++++++++++++++++++++++++++++++++++++++++++++++---------
 migration.h     |    2 +-
 2 files changed, 73 insertions(+), 15 deletions(-)
Anthony Liguori - June 1, 2010, 4:01 p.m.
On 06/01/2010 10:40 AM, Yoshiaki Tamura wrote:
> Create a thread to handle tcp incoming migration when CONFIG_IOTHREAD
> is enabled.  Spawned thread writes it's return status to th_fds[1]
> before exit, and main thread joins and reads it.  In
> tcp_start_incoming_migration(), allocate FdMigrationState and return
> MigrationState to let migration to print incoming migration info.
>    

In the absence of any locking, I can't see how this is safe.

Regards,

Anthony Liguori

> Signed-off-by: Yoshiaki Tamura<tamura.yoshiaki@lab.ntt.co.jp>
> ---
>   migration-tcp.c |   86 ++++++++++++++++++++++++++++++++++++++++++++++---------
>   migration.h     |    2 +-
>   2 files changed, 73 insertions(+), 15 deletions(-)
>
> diff --git a/migration-tcp.c b/migration-tcp.c
> index 95ce722..f20e5fe 100644
> --- a/migration-tcp.c
> +++ b/migration-tcp.c
> @@ -18,6 +18,7 @@
>   #include "sysemu.h"
>   #include "buffered_file.h"
>   #include "block.h"
> +#include "qemu-thread.h"
>
>   //#define DEBUG_MIGRATION_TCP
>
> @@ -29,6 +30,11 @@
>       do { } while (0)
>   #endif
>
> +#ifdef CONFIG_IOTHREAD
> +static QemuThread migration_thread;
> +static int th_fds[2];
> +#endif
> +
>   static int socket_errno(FdMigrationState *s)
>   {
>       return socket_error();
> @@ -176,41 +182,93 @@ static void tcp_accept_incoming_migration(void *opaque)
>   out_fopen:
>       qemu_fclose(f);
>   out:
> +#ifndef CONFIG_IOTHREAD
>       qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
> +#endif
>       close(s);
>       close(c);
> +#ifdef CONFIG_IOTHREAD
> +    write(th_fds[1],&ret, sizeof(ret));
> +    qemu_thread_exit(NULL);
> +#endif
> +}
> +
> +#ifdef CONFIG_IOTHREAD
> +static void tcp_incoming_migration_complete(void *opaque)
> +{
> +    int ret, state = 0;
> +    FdMigrationState *s = opaque;
> +
> +    qemu_thread_join(&migration_thread, NULL);
> +
> +    ret = read(th_fds[0],&state, sizeof(state));
> +    if (ret == -1) {
> +        fprintf(stderr, "failed to read from pipe\n");
> +        goto err;
> +    }
> +
> +    s->state = state<  0 ? MIG_STATE_ERROR : MIG_STATE_COMPLETED;
> +
> +err:
> +    qemu_set_fd_handler2(th_fds[0], NULL, NULL, NULL, NULL);
> +    close(th_fds[0]);
> +    close(th_fds[1]);
>   }
> +#endif
>
> -int tcp_start_incoming_migration(const char *host_port)
> +MigrationState *tcp_start_incoming_migration(const char *host_port)
>   {
>       struct sockaddr_in addr;
> +    FdMigrationState *s;
>       int val;
> -    int s;
>
>       if (parse_host_port(&addr, host_port)<  0) {
>           fprintf(stderr, "invalid host/port combination: %s\n", host_port);
> -        return -EINVAL;
> +        return NULL;
>       }
>
> -    s = qemu_socket(PF_INET, SOCK_STREAM, 0);
> -    if (s == -1)
> -        return -socket_error();
> +    s = qemu_mallocz(sizeof(*s));
> +
> +    s->get_error = socket_errno;
> +    s->close = tcp_close;
> +    s->mig_state.cancel = migrate_fd_cancel;
> +    s->mig_state.get_status = migrate_fd_get_status;
> +    s->state = MIG_STATE_ACTIVE;
> +
> +    s->fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
> +    if (s->fd == -1) {
> +        qemu_free(s);
> +        return NULL;
> +    }
>
>       val = 1;
> -    setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (const char *)&val, sizeof(val));
> +    setsockopt(s->fd, SOL_SOCKET, SO_REUSEADDR,
> +               (const char *)&val, sizeof(val));
>
> -    if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1)
> +    if (bind(s->fd, (struct sockaddr *)&addr, sizeof(addr)) == -1)
>           goto err;
>
> -    if (listen(s, 1) == -1)
> +    if (listen(s->fd, 1) == -1)
>           goto err;
>
> -    qemu_set_fd_handler2(s, NULL, tcp_accept_incoming_migration, NULL,
> -                         (void *)(unsigned long)s);
> +#ifdef CONFIG_IOTHREAD
> +    if (qemu_pipe(th_fds) == -1) {
> +        fprintf(stderr, "failed to create pipe\n");
> +        goto err;
> +    }
>
> -    return 0;
> +    qemu_thread_create(&migration_thread, (void *)tcp_accept_incoming_migration,
> +                       (void *)(unsigned long)s->fd);
> +    qemu_set_fd_handler2(th_fds[0], NULL, tcp_incoming_migration_complete, NULL,
> +                         (void *)s);
> +#else
> +    qemu_set_fd_handler2(s->fd, NULL, tcp_accept_incoming_migration, NULL,
> +                         (void *)(unsigned long)s->fd);
> +#endif
> +
> +    return&s->mig_state;
>
>   err:
> -    close(s);
> -    return -socket_error();
> +    close(s->fd);
> +    return NULL;
>   }
> diff --git a/migration.h b/migration.h
> index 385423f..c11e6db 100644
> --- a/migration.h
> +++ b/migration.h
> @@ -76,7 +76,7 @@ MigrationState *exec_start_outgoing_migration(Monitor *mon,
>   					      int blk,
>   					      int inc);
>
> -int tcp_start_incoming_migration(const char *host_port);
> +MigrationState *tcp_start_incoming_migration(const char *host_port);
>
>   MigrationState *tcp_start_outgoing_migration(Monitor *mon,
>                                                const char *host_port,
>
Yoshiaki Tamura - June 1, 2010, 4:23 p.m.
2010/6/2 Anthony Liguori <aliguori@linux.vnet.ibm.com>:
> On 06/01/2010 10:40 AM, Yoshiaki Tamura wrote:
>>
>> Create a thread to handle tcp incoming migration when CONFIG_IOTHREAD
>> is enabled.  Spawned thread writes it's return status to th_fds[1]
>> before exit, and main thread joins and reads it.  In
>> tcp_start_incoming_migration(), allocate FdMigrationState and return
>> MigrationState to let migration to print incoming migration info.
>>
>
> In the absence of any locking, I can't see how this is safe.

Right.  If we use threading here, we need to prevent commands from
monitor that affects incoming thread.

Thanks,

Yoshi

>
> Regards,
>
> Anthony Liguori
>
>> Signed-off-by: Yoshiaki Tamura<tamura.yoshiaki@lab.ntt.co.jp>
>> ---
>>  migration-tcp.c |   86
>> ++++++++++++++++++++++++++++++++++++++++++++++---------
>>  migration.h     |    2 +-
>>  2 files changed, 73 insertions(+), 15 deletions(-)
>>
>> diff --git a/migration-tcp.c b/migration-tcp.c
>> index 95ce722..f20e5fe 100644
>> --- a/migration-tcp.c
>> +++ b/migration-tcp.c
>> @@ -18,6 +18,7 @@
>>  #include "sysemu.h"
>>  #include "buffered_file.h"
>>  #include "block.h"
>> +#include "qemu-thread.h"
>>
>>  //#define DEBUG_MIGRATION_TCP
>>
>> @@ -29,6 +30,11 @@
>>      do { } while (0)
>>  #endif
>>
>> +#ifdef CONFIG_IOTHREAD
>> +static QemuThread migration_thread;
>> +static int th_fds[2];
>> +#endif
>> +
>>  static int socket_errno(FdMigrationState *s)
>>  {
>>      return socket_error();
>> @@ -176,41 +182,93 @@ static void tcp_accept_incoming_migration(void
>> *opaque)
>>  out_fopen:
>>      qemu_fclose(f);
>>  out:
>> +#ifndef CONFIG_IOTHREAD
>>      qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
>> +#endif
>>      close(s);
>>      close(c);
>> +#ifdef CONFIG_IOTHREAD
>> +    write(th_fds[1],&ret, sizeof(ret));
>> +    qemu_thread_exit(NULL);
>> +#endif
>> +}
>> +
>> +#ifdef CONFIG_IOTHREAD
>> +static void tcp_incoming_migration_complete(void *opaque)
>> +{
>> +    int ret, state = 0;
>> +    FdMigrationState *s = opaque;
>> +
>> +    qemu_thread_join(&migration_thread, NULL);
>> +
>> +    ret = read(th_fds[0],&state, sizeof(state));
>> +    if (ret == -1) {
>> +        fprintf(stderr, "failed to read from pipe\n");
>> +        goto err;
>> +    }
>> +
>> +    s->state = state<  0 ? MIG_STATE_ERROR : MIG_STATE_COMPLETED;
>> +
>> +err:
>> +    qemu_set_fd_handler2(th_fds[0], NULL, NULL, NULL, NULL);
>> +    close(th_fds[0]);
>> +    close(th_fds[1]);
>>  }
>> +#endif
>>
>> -int tcp_start_incoming_migration(const char *host_port)
>> +MigrationState *tcp_start_incoming_migration(const char *host_port)
>>  {
>>      struct sockaddr_in addr;
>> +    FdMigrationState *s;
>>      int val;
>> -    int s;
>>
>>      if (parse_host_port(&addr, host_port)<  0) {
>>          fprintf(stderr, "invalid host/port combination: %s\n",
>> host_port);
>> -        return -EINVAL;
>> +        return NULL;
>>      }
>>
>> -    s = qemu_socket(PF_INET, SOCK_STREAM, 0);
>> -    if (s == -1)
>> -        return -socket_error();
>> +    s = qemu_mallocz(sizeof(*s));
>> +
>> +    s->get_error = socket_errno;
>> +    s->close = tcp_close;
>> +    s->mig_state.cancel = migrate_fd_cancel;
>> +    s->mig_state.get_status = migrate_fd_get_status;
>> +    s->state = MIG_STATE_ACTIVE;
>> +
>> +    s->fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
>> +    if (s->fd == -1) {
>> +        qemu_free(s);
>> +        return NULL;
>> +    }
>>
>>      val = 1;
>> -    setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (const char *)&val,
>> sizeof(val));
>> +    setsockopt(s->fd, SOL_SOCKET, SO_REUSEADDR,
>> +               (const char *)&val, sizeof(val));
>>
>> -    if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1)
>> +    if (bind(s->fd, (struct sockaddr *)&addr, sizeof(addr)) == -1)
>>          goto err;
>>
>> -    if (listen(s, 1) == -1)
>> +    if (listen(s->fd, 1) == -1)
>>          goto err;
>>
>> -    qemu_set_fd_handler2(s, NULL, tcp_accept_incoming_migration, NULL,
>> -                         (void *)(unsigned long)s);
>> +#ifdef CONFIG_IOTHREAD
>> +    if (qemu_pipe(th_fds) == -1) {
>> +        fprintf(stderr, "failed to create pipe\n");
>> +        goto err;
>> +    }
>>
>> -    return 0;
>> +    qemu_thread_create(&migration_thread, (void
>> *)tcp_accept_incoming_migration,
>> +                       (void *)(unsigned long)s->fd);
>> +    qemu_set_fd_handler2(th_fds[0], NULL,
>> tcp_incoming_migration_complete, NULL,
>> +                         (void *)s);
>> +#else
>> +    qemu_set_fd_handler2(s->fd, NULL, tcp_accept_incoming_migration,
>> NULL,
>> +                         (void *)(unsigned long)s->fd);
>> +#endif
>> +
>> +    return&s->mig_state;
>>
>>  err:
>> -    close(s);
>> -    return -socket_error();
>> +    close(s->fd);
>> +    return NULL;
>>  }
>> diff --git a/migration.h b/migration.h
>> index 385423f..c11e6db 100644
>> --- a/migration.h
>> +++ b/migration.h
>> @@ -76,7 +76,7 @@ MigrationState *exec_start_outgoing_migration(Monitor
>> *mon,
>>                                              int blk,
>>                                              int inc);
>>
>> -int tcp_start_incoming_migration(const char *host_port);
>> +MigrationState *tcp_start_incoming_migration(const char *host_port);
>>
>>  MigrationState *tcp_start_outgoing_migration(Monitor *mon,
>>                                               const char *host_port,
>>
>
>
>
Anthony Liguori - June 1, 2010, 4:28 p.m.
On 06/01/2010 11:23 AM, Yoshiaki Tamura wrote:
> 2010/6/2 Anthony Liguori<aliguori@linux.vnet.ibm.com>:
>    
>> On 06/01/2010 10:40 AM, Yoshiaki Tamura wrote:
>>      
>>> Create a thread to handle tcp incoming migration when CONFIG_IOTHREAD
>>> is enabled.  Spawned thread writes it's return status to th_fds[1]
>>> before exit, and main thread joins and reads it.  In
>>> tcp_start_incoming_migration(), allocate FdMigrationState and return
>>> MigrationState to let migration to print incoming migration info.
>>>
>>>        
>> In the absence of any locking, I can't see how this is safe.
>>      
> Right.  If we use threading here, we need to prevent commands from
> monitor that affects incoming thread.
>    

There's a huge number of calls that can get made during live migration 
that can also be triggered by the monitor.

Even the basic things likes qemu_set_fd_handler2 can cause havoc.

Just preventing certain monitor commands is not sufficient.

Regards,

Anthony Liguori

> Thanks,
>
> Yoshi
>
>    
>> Regards,
>>
>> Anthony Liguori
>>
>>      
>>> Signed-off-by: Yoshiaki Tamura<tamura.yoshiaki@lab.ntt.co.jp>
>>> ---
>>>   migration-tcp.c |   86
>>> ++++++++++++++++++++++++++++++++++++++++++++++---------
>>>   migration.h     |    2 +-
>>>   2 files changed, 73 insertions(+), 15 deletions(-)
>>>
>>> diff --git a/migration-tcp.c b/migration-tcp.c
>>> index 95ce722..f20e5fe 100644
>>> --- a/migration-tcp.c
>>> +++ b/migration-tcp.c
>>> @@ -18,6 +18,7 @@
>>>   #include "sysemu.h"
>>>   #include "buffered_file.h"
>>>   #include "block.h"
>>> +#include "qemu-thread.h"
>>>
>>>   //#define DEBUG_MIGRATION_TCP
>>>
>>> @@ -29,6 +30,11 @@
>>>       do { } while (0)
>>>   #endif
>>>
>>> +#ifdef CONFIG_IOTHREAD
>>> +static QemuThread migration_thread;
>>> +static int th_fds[2];
>>> +#endif
>>> +
>>>   static int socket_errno(FdMigrationState *s)
>>>   {
>>>       return socket_error();
>>> @@ -176,41 +182,93 @@ static void tcp_accept_incoming_migration(void
>>> *opaque)
>>>   out_fopen:
>>>       qemu_fclose(f);
>>>   out:
>>> +#ifndef CONFIG_IOTHREAD
>>>       qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
>>> +#endif
>>>       close(s);
>>>       close(c);
>>> +#ifdef CONFIG_IOTHREAD
>>> +    write(th_fds[1],&ret, sizeof(ret));
>>> +    qemu_thread_exit(NULL);
>>> +#endif
>>> +}
>>> +
>>> +#ifdef CONFIG_IOTHREAD
>>> +static void tcp_incoming_migration_complete(void *opaque)
>>> +{
>>> +    int ret, state = 0;
>>> +    FdMigrationState *s = opaque;
>>> +
>>> +    qemu_thread_join(&migration_thread, NULL);
>>> +
>>> +    ret = read(th_fds[0],&state, sizeof(state));
>>> +    if (ret == -1) {
>>> +        fprintf(stderr, "failed to read from pipe\n");
>>> +        goto err;
>>> +    }
>>> +
>>> +    s->state = state<    0 ? MIG_STATE_ERROR : MIG_STATE_COMPLETED;
>>> +
>>> +err:
>>> +    qemu_set_fd_handler2(th_fds[0], NULL, NULL, NULL, NULL);
>>> +    close(th_fds[0]);
>>> +    close(th_fds[1]);
>>>   }
>>> +#endif
>>>
>>> -int tcp_start_incoming_migration(const char *host_port)
>>> +MigrationState *tcp_start_incoming_migration(const char *host_port)
>>>   {
>>>       struct sockaddr_in addr;
>>> +    FdMigrationState *s;
>>>       int val;
>>> -    int s;
>>>
>>>       if (parse_host_port(&addr, host_port)<    0) {
>>>           fprintf(stderr, "invalid host/port combination: %s\n",
>>> host_port);
>>> -        return -EINVAL;
>>> +        return NULL;
>>>       }
>>>
>>> -    s = qemu_socket(PF_INET, SOCK_STREAM, 0);
>>> -    if (s == -1)
>>> -        return -socket_error();
>>> +    s = qemu_mallocz(sizeof(*s));
>>> +
>>> +    s->get_error = socket_errno;
>>> +    s->close = tcp_close;
>>> +    s->mig_state.cancel = migrate_fd_cancel;
>>> +    s->mig_state.get_status = migrate_fd_get_status;
>>> +    s->state = MIG_STATE_ACTIVE;
>>> +
>>> +    s->fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
>>> +    if (s->fd == -1) {
>>> +        qemu_free(s);
>>> +        return NULL;
>>> +    }
>>>
>>>       val = 1;
>>> -    setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (const char *)&val,
>>> sizeof(val));
>>> +    setsockopt(s->fd, SOL_SOCKET, SO_REUSEADDR,
>>> +               (const char *)&val, sizeof(val));
>>>
>>> -    if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1)
>>> +    if (bind(s->fd, (struct sockaddr *)&addr, sizeof(addr)) == -1)
>>>           goto err;
>>>
>>> -    if (listen(s, 1) == -1)
>>> +    if (listen(s->fd, 1) == -1)
>>>           goto err;
>>>
>>> -    qemu_set_fd_handler2(s, NULL, tcp_accept_incoming_migration, NULL,
>>> -                         (void *)(unsigned long)s);
>>> +#ifdef CONFIG_IOTHREAD
>>> +    if (qemu_pipe(th_fds) == -1) {
>>> +        fprintf(stderr, "failed to create pipe\n");
>>> +        goto err;
>>> +    }
>>>
>>> -    return 0;
>>> +    qemu_thread_create(&migration_thread, (void
>>> *)tcp_accept_incoming_migration,
>>> +                       (void *)(unsigned long)s->fd);
>>> +    qemu_set_fd_handler2(th_fds[0], NULL,
>>> tcp_incoming_migration_complete, NULL,
>>> +                         (void *)s);
>>> +#else
>>> +    qemu_set_fd_handler2(s->fd, NULL, tcp_accept_incoming_migration,
>>> NULL,
>>> +                         (void *)(unsigned long)s->fd);
>>> +#endif
>>> +
>>> +    return&s->mig_state;
>>>
>>>   err:
>>> -    close(s);
>>> -    return -socket_error();
>>> +    close(s->fd);
>>> +    return NULL;
>>>   }
>>> diff --git a/migration.h b/migration.h
>>> index 385423f..c11e6db 100644
>>> --- a/migration.h
>>> +++ b/migration.h
>>> @@ -76,7 +76,7 @@ MigrationState *exec_start_outgoing_migration(Monitor
>>> *mon,
>>>                                               int blk,
>>>                                               int inc);
>>>
>>> -int tcp_start_incoming_migration(const char *host_port);
>>> +MigrationState *tcp_start_incoming_migration(const char *host_port);
>>>
>>>   MigrationState *tcp_start_outgoing_migration(Monitor *mon,
>>>                                                const char *host_port,
>>>
>>>        
>>
>>
>>
Yoshiaki Tamura - June 1, 2010, 4:46 p.m.
2010/6/2 Anthony Liguori <aliguori@linux.vnet.ibm.com>:
> On 06/01/2010 11:23 AM, Yoshiaki Tamura wrote:
>>
>> 2010/6/2 Anthony Liguori<aliguori@linux.vnet.ibm.com>:
>>
>>>
>>> On 06/01/2010 10:40 AM, Yoshiaki Tamura wrote:
>>>
>>>>
>>>> Create a thread to handle tcp incoming migration when CONFIG_IOTHREAD
>>>> is enabled.  Spawned thread writes it's return status to th_fds[1]
>>>> before exit, and main thread joins and reads it.  In
>>>> tcp_start_incoming_migration(), allocate FdMigrationState and return
>>>> MigrationState to let migration to print incoming migration info.
>>>>
>>>>
>>>
>>> In the absence of any locking, I can't see how this is safe.
>>>
>>
>> Right.  If we use threading here, we need to prevent commands from
>> monitor that affects incoming thread.
>>
>
> There's a huge number of calls that can get made during live migration that
> can also be triggered by the monitor.
>
> Even the basic things likes qemu_set_fd_handler2 can cause havoc.
>
> Just preventing certain monitor commands is not sufficient.

Ah, that was my concern.  Sorry for not understanding well.
Thanks for your advice.

Yoshi

>
> Regards,
>
> Anthony Liguori
>
>> Thanks,
>>
>> Yoshi
>>
>>
>>>
>>> Regards,
>>>
>>> Anthony Liguori
>>>
>>>
>>>>
>>>> Signed-off-by: Yoshiaki Tamura<tamura.yoshiaki@lab.ntt.co.jp>
>>>> ---
>>>>  migration-tcp.c |   86
>>>> ++++++++++++++++++++++++++++++++++++++++++++++---------
>>>>  migration.h     |    2 +-
>>>>  2 files changed, 73 insertions(+), 15 deletions(-)
>>>>
>>>> diff --git a/migration-tcp.c b/migration-tcp.c
>>>> index 95ce722..f20e5fe 100644
>>>> --- a/migration-tcp.c
>>>> +++ b/migration-tcp.c
>>>> @@ -18,6 +18,7 @@
>>>>  #include "sysemu.h"
>>>>  #include "buffered_file.h"
>>>>  #include "block.h"
>>>> +#include "qemu-thread.h"
>>>>
>>>>  //#define DEBUG_MIGRATION_TCP
>>>>
>>>> @@ -29,6 +30,11 @@
>>>>      do { } while (0)
>>>>  #endif
>>>>
>>>> +#ifdef CONFIG_IOTHREAD
>>>> +static QemuThread migration_thread;
>>>> +static int th_fds[2];
>>>> +#endif
>>>> +
>>>>  static int socket_errno(FdMigrationState *s)
>>>>  {
>>>>      return socket_error();
>>>> @@ -176,41 +182,93 @@ static void tcp_accept_incoming_migration(void
>>>> *opaque)
>>>>  out_fopen:
>>>>      qemu_fclose(f);
>>>>  out:
>>>> +#ifndef CONFIG_IOTHREAD
>>>>      qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
>>>> +#endif
>>>>      close(s);
>>>>      close(c);
>>>> +#ifdef CONFIG_IOTHREAD
>>>> +    write(th_fds[1],&ret, sizeof(ret));
>>>> +    qemu_thread_exit(NULL);
>>>> +#endif
>>>> +}
>>>> +
>>>> +#ifdef CONFIG_IOTHREAD
>>>> +static void tcp_incoming_migration_complete(void *opaque)
>>>> +{
>>>> +    int ret, state = 0;
>>>> +    FdMigrationState *s = opaque;
>>>> +
>>>> +    qemu_thread_join(&migration_thread, NULL);
>>>> +
>>>> +    ret = read(th_fds[0],&state, sizeof(state));
>>>> +    if (ret == -1) {
>>>> +        fprintf(stderr, "failed to read from pipe\n");
>>>> +        goto err;
>>>> +    }
>>>> +
>>>> +    s->state = state<    0 ? MIG_STATE_ERROR : MIG_STATE_COMPLETED;
>>>> +
>>>> +err:
>>>> +    qemu_set_fd_handler2(th_fds[0], NULL, NULL, NULL, NULL);
>>>> +    close(th_fds[0]);
>>>> +    close(th_fds[1]);
>>>>  }
>>>> +#endif
>>>>
>>>> -int tcp_start_incoming_migration(const char *host_port)
>>>> +MigrationState *tcp_start_incoming_migration(const char *host_port)
>>>>  {
>>>>      struct sockaddr_in addr;
>>>> +    FdMigrationState *s;
>>>>      int val;
>>>> -    int s;
>>>>
>>>>      if (parse_host_port(&addr, host_port)<    0) {
>>>>          fprintf(stderr, "invalid host/port combination: %s\n",
>>>> host_port);
>>>> -        return -EINVAL;
>>>> +        return NULL;
>>>>      }
>>>>
>>>> -    s = qemu_socket(PF_INET, SOCK_STREAM, 0);
>>>> -    if (s == -1)
>>>> -        return -socket_error();
>>>> +    s = qemu_mallocz(sizeof(*s));
>>>> +
>>>> +    s->get_error = socket_errno;
>>>> +    s->close = tcp_close;
>>>> +    s->mig_state.cancel = migrate_fd_cancel;
>>>> +    s->mig_state.get_status = migrate_fd_get_status;
>>>> +    s->state = MIG_STATE_ACTIVE;
>>>> +
>>>> +    s->fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
>>>> +    if (s->fd == -1) {
>>>> +        qemu_free(s);
>>>> +        return NULL;
>>>> +    }
>>>>
>>>>      val = 1;
>>>> -    setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (const char *)&val,
>>>> sizeof(val));
>>>> +    setsockopt(s->fd, SOL_SOCKET, SO_REUSEADDR,
>>>> +               (const char *)&val, sizeof(val));
>>>>
>>>> -    if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1)
>>>> +    if (bind(s->fd, (struct sockaddr *)&addr, sizeof(addr)) == -1)
>>>>          goto err;
>>>>
>>>> -    if (listen(s, 1) == -1)
>>>> +    if (listen(s->fd, 1) == -1)
>>>>          goto err;
>>>>
>>>> -    qemu_set_fd_handler2(s, NULL, tcp_accept_incoming_migration, NULL,
>>>> -                         (void *)(unsigned long)s);
>>>> +#ifdef CONFIG_IOTHREAD
>>>> +    if (qemu_pipe(th_fds) == -1) {
>>>> +        fprintf(stderr, "failed to create pipe\n");
>>>> +        goto err;
>>>> +    }
>>>>
>>>> -    return 0;
>>>> +    qemu_thread_create(&migration_thread, (void
>>>> *)tcp_accept_incoming_migration,
>>>> +                       (void *)(unsigned long)s->fd);
>>>> +    qemu_set_fd_handler2(th_fds[0], NULL,
>>>> tcp_incoming_migration_complete, NULL,
>>>> +                         (void *)s);
>>>> +#else
>>>> +    qemu_set_fd_handler2(s->fd, NULL, tcp_accept_incoming_migration,
>>>> NULL,
>>>> +                         (void *)(unsigned long)s->fd);
>>>> +#endif
>>>> +
>>>> +    return&s->mig_state;
>>>>
>>>>  err:
>>>> -    close(s);
>>>> -    return -socket_error();
>>>> +    close(s->fd);
>>>> +    return NULL;
>>>>  }
>>>> diff --git a/migration.h b/migration.h
>>>> index 385423f..c11e6db 100644
>>>> --- a/migration.h
>>>> +++ b/migration.h
>>>> @@ -76,7 +76,7 @@ MigrationState *exec_start_outgoing_migration(Monitor
>>>> *mon,
>>>>                                              int blk,
>>>>                                              int inc);
>>>>
>>>> -int tcp_start_incoming_migration(const char *host_port);
>>>> +MigrationState *tcp_start_incoming_migration(const char *host_port);
>>>>
>>>>  MigrationState *tcp_start_outgoing_migration(Monitor *mon,
>>>>                                               const char *host_port,
>>>>
>>>>
>>>
>>>
>>>
>
>
>

Patch

diff --git a/migration-tcp.c b/migration-tcp.c
index 95ce722..f20e5fe 100644
--- a/migration-tcp.c
+++ b/migration-tcp.c
@@ -18,6 +18,7 @@ 
 #include "sysemu.h"
 #include "buffered_file.h"
 #include "block.h"
+#include "qemu-thread.h"
 
 //#define DEBUG_MIGRATION_TCP
 
@@ -29,6 +30,11 @@ 
     do { } while (0)
 #endif
 
+#ifdef CONFIG_IOTHREAD
+static QemuThread migration_thread;
+static int th_fds[2];
+#endif
+
 static int socket_errno(FdMigrationState *s)
 {
     return socket_error();
@@ -176,41 +182,93 @@  static void tcp_accept_incoming_migration(void *opaque)
 out_fopen:
     qemu_fclose(f);
 out:
+#ifndef CONFIG_IOTHREAD
     qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
+#endif
     close(s);
     close(c);
+#ifdef CONFIG_IOTHREAD
+    write(th_fds[1], &ret, sizeof(ret));
+    qemu_thread_exit(NULL);
+#endif
+}
+
+#ifdef CONFIG_IOTHREAD
+static void tcp_incoming_migration_complete(void *opaque)
+{
+    int ret, state = 0;
+    FdMigrationState *s = opaque;
+
+    qemu_thread_join(&migration_thread, NULL);
+
+    ret = read(th_fds[0], &state, sizeof(state));
+    if (ret == -1) {
+        fprintf(stderr, "failed to read from pipe\n");        
+        goto err;
+    }
+
+    s->state = state < 0 ? MIG_STATE_ERROR : MIG_STATE_COMPLETED;
+
+err:
+    qemu_set_fd_handler2(th_fds[0], NULL, NULL, NULL, NULL);
+    close(th_fds[0]);
+    close(th_fds[1]);
 }
+#endif
 
-int tcp_start_incoming_migration(const char *host_port)
+MigrationState *tcp_start_incoming_migration(const char *host_port)
 {
     struct sockaddr_in addr;
+    FdMigrationState *s;
     int val;
-    int s;
 
     if (parse_host_port(&addr, host_port) < 0) {
         fprintf(stderr, "invalid host/port combination: %s\n", host_port);
-        return -EINVAL;
+        return NULL;
     }
 
-    s = qemu_socket(PF_INET, SOCK_STREAM, 0);
-    if (s == -1)
-        return -socket_error();
+    s = qemu_mallocz(sizeof(*s));
+
+    s->get_error = socket_errno;
+    s->close = tcp_close;
+    s->mig_state.cancel = migrate_fd_cancel;
+    s->mig_state.get_status = migrate_fd_get_status;
+    s->state = MIG_STATE_ACTIVE;
+
+    s->fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
+    if (s->fd == -1) {
+        qemu_free(s);
+        return NULL;
+    }
 
     val = 1;
-    setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (const char *)&val, sizeof(val));
+    setsockopt(s->fd, SOL_SOCKET, SO_REUSEADDR,
+               (const char *)&val, sizeof(val));
 
-    if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1)
+    if (bind(s->fd, (struct sockaddr *)&addr, sizeof(addr)) == -1)
         goto err;
 
-    if (listen(s, 1) == -1)
+    if (listen(s->fd, 1) == -1)
         goto err;
 
-    qemu_set_fd_handler2(s, NULL, tcp_accept_incoming_migration, NULL,
-                         (void *)(unsigned long)s);
+#ifdef CONFIG_IOTHREAD
+    if (qemu_pipe(th_fds) == -1) {
+        fprintf(stderr, "failed to create pipe\n");
+        goto err;
+    }
 
-    return 0;
+    qemu_thread_create(&migration_thread, (void *)tcp_accept_incoming_migration,
+                       (void *)(unsigned long)s->fd);
+    qemu_set_fd_handler2(th_fds[0], NULL, tcp_incoming_migration_complete, NULL,
+                         (void *)s);
+#else
+    qemu_set_fd_handler2(s->fd, NULL, tcp_accept_incoming_migration, NULL,
+                         (void *)(unsigned long)s->fd);
+#endif
+
+    return &s->mig_state;
 
 err:
-    close(s);
-    return -socket_error();
+    close(s->fd);
+    return NULL;
 }
diff --git a/migration.h b/migration.h
index 385423f..c11e6db 100644
--- a/migration.h
+++ b/migration.h
@@ -76,7 +76,7 @@  MigrationState *exec_start_outgoing_migration(Monitor *mon,
 					      int blk,
 					      int inc);
 
-int tcp_start_incoming_migration(const char *host_port);
+MigrationState *tcp_start_incoming_migration(const char *host_port);
 
 MigrationState *tcp_start_outgoing_migration(Monitor *mon,
                                              const char *host_port,