Re: [Qemu-devel] [PULL v3 2/7] rdma: new QEMUFileOps hooks

[Orit Wasserman <owasserm@redhat.com>]

On 04/17/2013 01:17 PM, Paolo Bonzini wrote:
> Il 17/04/2013 12:13, Orit Wasserman ha scritto:
>> On 04/17/2013 07:20 AM, mrhines@linux.vnet.ibm.com wrote:
>>> From: "Michael R. Hines" <mrhines@us.ibm.com>
>>>
>>> These are the prototypes and implementation of new hooks that
>>> RDMA takes advantage of to perform dynamic page registration.
>>>
>>> An optional hook is also introduced for a custom function
>>> to be able to override the default save_page function.
>>>
>>> Also included are the prototypes and accessor methods used by
>>> arch_init.c which invoke funtions inside savevm.c to call out
>>> to the hooks that may or may not have been overridden
>>> inside of QEMUFileOps.
>>>
>>> Signed-off-by: Michael R. Hines <mrhines@us.ibm.com>
>>> ---
>>>  include/migration/migration.h |   19 ++++++++++
>>>  include/migration/qemu-file.h |   31 ++++++++++++++++
>>>  savevm.c                      |   79 ++++++++++++++++++++++++++++++++++++-----
>>>  3 files changed, 121 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/include/migration/migration.h b/include/migration/migration.h
>>> index e2acec6..8e02391 100644
>>> --- a/include/migration/migration.h
>>> +++ b/include/migration/migration.h
>>> @@ -21,6 +21,7 @@
>>>  #include "qapi/error.h"
>>>  #include "migration/vmstate.h"
>>>  #include "qapi-types.h"
>>> +#include "exec/cpu-common.h"
>>
>> Is this include needed here?
> 
> I think it's for ram_addr_t.
> 
> Paolo
> 

Yes I missed that.

>>>  
>>>  struct MigrationParams {
>>>      bool blk;
>>> @@ -127,4 +128,22 @@ int migrate_use_xbzrle(void);
>>>  int64_t migrate_xbzrle_cache_size(void);
>>>  
>>>  int64_t xbzrle_cache_resize(int64_t new_size);
>>> +
>>> +void ram_handle_compressed(void *host, uint8_t ch, uint64_t size);
>>> +
>>> +bool migrate_chunk_register_destination(void);
>>> +void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
>>> +void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
>>> +void ram_control_load_hook(QEMUFile *f, uint64_t flags);
>>> +
>>> +/* Whenever this is found in the data stream, the flags
>>> + * will be passed to ram_control_load_hook in the incoming-migration
>>> + * side. This lets before_ram_iterate/after_ram_iterate add
>>> + * transport-specific sections to the RAM migration data.
>>> + */
>>> +#define RAM_SAVE_FLAG_HOOK     0x80
>>> +
>>> +size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
>>> +                             ram_addr_t offset, size_t size);
>>> +
>>>  #endif
>>> diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
>>> index 7519464..5166a42 100644
>>> --- a/include/migration/qemu-file.h
>>> +++ b/include/migration/qemu-file.h
>>> @@ -23,6 +23,7 @@
>>>   */
>>>  #ifndef QEMU_FILE_H
>>>  #define QEMU_FILE_H 1
>>> +#include "exec/cpu-common.h"
>>>  
>>>  /* This function writes a chunk of data to a file at the given position.
>>>   * The pos argument can be ignored if the file is only being used for
>>> @@ -57,12 +58,39 @@ typedef int (QEMUFileGetFD)(void *opaque);
>>>  typedef ssize_t (QEMUFileWritevBufferFunc)(void *opaque, struct iovec *iov,
>>>                                             int iovcnt, int64_t pos);
>>>  
>>> +/*
>>> + * This function provides hooks around different
>>> + * stages of RAM migration.
>>> + */
>>> +typedef int (QEMURamHookFunc)(QEMUFile *f, void *opaque, uint64_t flags);
>>> +
>>> +/*
>>> + * Constants used by ram_control_* hooks
>>> + */
>>> +#define RAM_CONTROL_SETUP    0
>>> +#define RAM_CONTROL_ROUND    1
>>> +#define RAM_CONTROL_HOOK     2
>>> +#define RAM_CONTROL_FINISH   3
>>> +
>>> +/*
>>> + * This function allows override of where the RAM page
>>> + * is saved (such as RDMA, for example.)
>>> + */
>>> +typedef size_t (QEMURamSaveFunc)(QEMUFile *f, void *opaque,
>>> +                               ram_addr_t block_offset,
>>> +                               ram_addr_t offset,
>>> +                               size_t size);
>>> +
>>>  typedef struct QEMUFileOps {
>>>      QEMUFilePutBufferFunc *put_buffer;
>>>      QEMUFileGetBufferFunc *get_buffer;
>>>      QEMUFileCloseFunc *close;
>>>      QEMUFileGetFD *get_fd;
>>>      QEMUFileWritevBufferFunc *writev_buffer;
>>> +    QEMURamHookFunc *before_ram_iterate;
>>> +    QEMURamHookFunc *after_ram_iterate;
>>> +    QEMURamHookFunc *hook_ram_load;
>>> +    QEMURamSaveFunc *save_page;
>>>  } QEMUFileOps;
>>>  
>>>  QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops);
>>> @@ -81,6 +109,8 @@ void qemu_put_byte(QEMUFile *f, int v);
>>>   */
>>>  void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, int size);
>>>  
>>> +bool qemu_file_mode_is_not_valid(const char *mode);
>>> +
>>
>> This should be in a separate patch as it not related to the new hooks 
>> you can add a new patch for adding qemu_file_mode_is_invalid func
>>
>>>  static inline void qemu_put_ubyte(QEMUFile *f, unsigned int v)
>>>  {
>>>      qemu_put_byte(f, (int)v);
>>> @@ -110,6 +140,7 @@ void qemu_file_reset_rate_limit(QEMUFile *f);
>>>  void qemu_file_set_rate_limit(QEMUFile *f, int64_t new_rate);
>>>  int64_t qemu_file_get_rate_limit(QEMUFile *f);
>>>  int qemu_file_get_error(QEMUFile *f);
>>> +void qemu_fflush(QEMUFile *f);
>>
>> This also should not be in this patch but in a separate patch
>>  (probably didn't read the rest of the patches yet)
>>
>> Orit
>>
>>>  
>>>  static inline void qemu_put_be64s(QEMUFile *f, const uint64_t *pv)
>>>  {
>>> diff --git a/savevm.c b/savevm.c
>>> index 53515cb..cdb1690 100644
>>> --- a/savevm.c
>>> +++ b/savevm.c
>>> @@ -409,14 +409,23 @@ static const QEMUFileOps socket_write_ops = {
>>>      .close =      socket_close
>>>  };
>>>  
>>> -QEMUFile *qemu_fopen_socket(int fd, const char *mode)
>>> +bool qemu_file_mode_is_not_valid(const char *mode)
>>>  {
>>> -    QEMUFileSocket *s = g_malloc0(sizeof(QEMUFileSocket));
>>> -
>>>      if (mode == NULL ||
>>>          (mode[0] != 'r' && mode[0] != 'w') ||
>>>          mode[1] != 'b' || mode[2] != 0) {
>>>          fprintf(stderr, "qemu_fopen: Argument validity check failed\n");
>>> +        return true;
>>> +    }
>>> +
>>> +    return false;
>>> +}
>>> +
>>> +QEMUFile *qemu_fopen_socket(int fd, const char *mode)
>>> +{
>>> +    QEMUFileSocket *s = g_malloc0(sizeof(QEMUFileSocket));
>>> +
>>> +    if (qemu_file_mode_is_not_valid(mode)) {
>>>          return NULL;
>>>      }
>>>  
>>> @@ -434,10 +443,7 @@ QEMUFile *qemu_fopen(const char *filename, const char *mode)
>>>  {
>>>      QEMUFileStdio *s;
>>>  
>>> -    if (mode == NULL ||
>>> -	(mode[0] != 'r' && mode[0] != 'w') ||
>>> -	mode[1] != 'b' || mode[2] != 0) {
>>> -        fprintf(stderr, "qemu_fopen: Argument validity check failed\n");
>>> +    if (qemu_file_mode_is_not_valid(mode)) {
>>>          return NULL;
>>>      }
>>>  
>>> @@ -542,7 +548,7 @@ static inline bool qemu_file_is_writable(QEMUFile *f)
>>>   * If there is writev_buffer QEMUFileOps it uses it otherwise uses
>>>   * put_buffer ops.
>>>   */
>>> -static void qemu_fflush(QEMUFile *f)
>>> +void qemu_fflush(QEMUFile *f)
>>>  {
>>>      ssize_t ret = 0;
>>>  
>>> @@ -569,6 +575,63 @@ static void qemu_fflush(QEMUFile *f)
>>>      }
>>>  }
>>>  
>>> +void ram_control_before_iterate(QEMUFile *f, uint64_t flags)
>>> +{
>>> +    int ret = 0;
>>> +
>>> +    if (f->ops->before_ram_iterate) {
>>> +        ret = f->ops->before_ram_iterate(f, f->opaque, flags);
>>> +        if (ret < 0) {
>>> +            qemu_file_set_error(f, ret);
>>> +        }
>>> +    }
>>> +}
>>> +
>>> +void ram_control_after_iterate(QEMUFile *f, uint64_t flags)
>>> +{
>>> +    int ret = 0;
>>> +
>>> +    if (f->ops->after_ram_iterate) {
>>> +        ret = f->ops->after_ram_iterate(f, f->opaque, flags);
>>> +        if (ret < 0) {
>>> +            qemu_file_set_error(f, ret);
>>> +        }
>>> +    }
>>> +}
>>> +
>>> +void ram_control_load_hook(QEMUFile *f, uint64_t flags)
>>> +{
>>> +    int ret = 0;
>>> +
>>> +    if (f->ops->hook_ram_load) {
>>> +        ret = f->ops->hook_ram_load(f, f->opaque, flags);
>>> +        if (ret < 0) {
>>> +            qemu_file_set_error(f, ret);
>>> +        }
>>> +    } else {
>>> +        qemu_file_set_error(f, ret);
>>> +    }
>>> +}
>>> +
>>> +size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
>>> +                             ram_addr_t offset, size_t size)
>>> +{
>>> +    if (f->ops->save_page) {
>>> +        int64_t bytes;
>>> +        bytes = f->ops->save_page(f, f->opaque, block_offset, offset, size);
>>> +
>>> +        if (bytes >= 0) {
>>> +            f->pos += bytes;
>>> +        } else {
>>> +            qemu_file_set_error(f, bytes);
>>> +        }
>>> +
>>> +        return bytes;
>>> +    }
>>> +
>>> +    return -1;
>>> +}
>>> +
>>>  static void qemu_fill_buffer(QEMUFile *f)
>>>  {
>>>      int len;
>>>
>>
>