Re: [Qemu-devel] [PATCH v7 12/42] Migration commands

[Dr. David Alan Gilbert]

* Juan Quintela (address@hidden) wrote:
> "Dr. David Alan Gilbert (git)" <address@hidden> wrote:
> > From: "Dr. David Alan Gilbert" <address@hidden>
> >
> > Create QEMU_VM_COMMAND section type for sending commands from
> > source to destination.  These commands are not intended to convey
> > guest state but to control the migration process.
> >
> > For use in postcopy.
> >
> > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> > ---
> >  include/migration/migration.h |  1 +
> >  include/sysemu/sysemu.h       |  7 +++++++
> >  migration/savevm.c            | 46 
> > +++++++++++++++++++++++++++++++++++++++++++
> >  trace-events                  |  1 +
> >  4 files changed, 55 insertions(+)
> >
> > diff --git a/include/migration/migration.h b/include/migration/migration.h
> > index 414c5cf..8adaa45 100644
> > --- a/include/migration/migration.h
> > +++ b/include/migration/migration.h
> > @@ -34,6 +34,7 @@
> >  #define QEMU_VM_SECTION_FULL         0x04
> >  #define QEMU_VM_SUBSECTION           0x05
> >  #define QEMU_VM_VMDESCRIPTION        0x06
> > +#define QEMU_VM_COMMAND              0x07
> 
> conflicts with configuration section just sent

Inc'd to 8.

> >  #define QEMU_VM_SECTION_FOOTER       0x7e
> >  
> >  struct MigrationParams {
> > diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
> > index 6dae2db..5869607 100644
> > --- a/include/sysemu/sysemu.h
> > +++ b/include/sysemu/sysemu.h
> > @@ -82,6 +82,11 @@ void hmp_info_snapshots(Monitor *mon, const QDict 
> > *qdict);
> >  
> >  void qemu_announce_self(void);
> >  
> > +/* Subcommands for QEMU_VM_COMMAND */
> > +enum qemu_vm_cmd {
> > +    MIG_CMD_INVALID = 0,   /* Must be 0 */
> > +};
> > +
> >  bool qemu_savevm_state_blocked(Error **errp);
> >  void qemu_savevm_state_begin(QEMUFile *f,
> >                               const MigrationParams *params);
> > @@ -90,6 +95,8 @@ int qemu_savevm_state_iterate(QEMUFile *f);
> >  void qemu_savevm_state_complete_precopy(QEMUFile *f);
> >  void qemu_savevm_state_cancel(void);
> >  uint64_t qemu_savevm_state_pending(QEMUFile *f, uint64_t max_size);
> > +void qemu_savevm_command_send(QEMUFile *f, enum qemu_vm_cmd command,
> > +                              uint16_t len, uint8_t *data);
> >  int qemu_loadvm_state(QEMUFile *f);
> >  
> >  typedef enum DisplayType
> > diff --git a/migration/savevm.c b/migration/savevm.c
> > index f9168ac..7ce9d21 100644
> > --- a/migration/savevm.c
> > +++ b/migration/savevm.c
> > @@ -686,6 +686,23 @@ static bool check_section_footer(QEMUFile *f, 
> > SaveStateEntry *se)
> >      return true;
> >  }
> >  
> > +/* Send a 'QEMU_VM_COMMAND' type element with the command
> > + * and associated data.
> 
> Please, use doxygen comments for new functions :p

Done.

> 
> > + */
> > +void qemu_savevm_command_send(QEMUFile *f,
> > +                              enum qemu_vm_cmd command,
> > +                              uint16_t len,
> > +                              uint8_t *data)
> > +{
> > +    qemu_put_byte(f, QEMU_VM_COMMAND);
> > +    qemu_put_be16(f, (uint16_t)command);
> > +    qemu_put_be16(f, len);
> > +    if (len) {
> > +        qemu_put_buffer(f, data, len);
> > +    }
> > +    qemu_fflush(f);
> > +}
> > +
> >  bool qemu_savevm_state_blocked(Error **errp)
> >  {
> >      SaveStateEntry *se;
> > @@ -982,6 +999,29 @@ static SaveStateEntry *find_se(const char *idstr, int 
> > instance_id)
> >      return NULL;
> >  }
> >  
> > +/*
> > + * Process an incoming 'QEMU_VM_COMMAND'
> > + * negative return on error (will issue error message)
> > + */
> > +static int loadvm_process_command(QEMUFile *f)
> > +{
> > +    uint16_t cmd;
> > +    uint16_t len;
> > +
> > +    cmd = qemu_get_be16(f);
> > +    len = qemu_get_be16(f);
> > +
> > +    trace_loadvm_process_command(cmd, len);
> 
> trace for load but not for sending?

Added.

Dave

> > +    switch (cmd) {
> > +
> > +    default:
> > +        error_report("VM_COMMAND 0x%x unknown (len 0x%x)", cmd, len);
> > +        return -1;
> > +    }
> > +
> > +    return 0;
> > +}
> > +
> >  struct LoadStateEntry {
> >      QLIST_ENTRY(LoadStateEntry) entry;
> >      SaveStateEntry *se;
> > @@ -1114,6 +1154,12 @@ int qemu_loadvm_state(QEMUFile *f)
> >                  goto out;
> >              }
> >              break;
> > +        case QEMU_VM_COMMAND:
> > +            ret = loadvm_process_command(f);
> > +            if (ret < 0) {
> > +                goto out;
> > +            }
> > +            break;
> >          default:
> >              error_report("Unknown savevm section type %d", section_type);
> >              ret = -EINVAL;
> > diff --git a/trace-events b/trace-events
> > index d539528..73a65c3 100644
> > --- a/trace-events
> > +++ b/trace-events
> > @@ -1183,6 +1183,7 @@ virtio_gpu_fence_resp(uint64_t fence) "fence 0x%" 
> > PRIx64
> >  qemu_loadvm_state_section(unsigned int section_type) "%d"
> >  qemu_loadvm_state_section_partend(uint32_t section_id) "%u"
> >  qemu_loadvm_state_section_startfull(uint32_t section_id, const char 
> > *idstr, uint32_t instance_id, uint32_t version_id) "%u(%s) %u %u"
> > +loadvm_process_command(uint16_t com, uint16_t len) "com=0x%x len=%d"
> >  savevm_section_start(const char *id, unsigned int section_id) "%s, 
> > section_id %u"
> >  savevm_section_end(const char *id, unsigned int section_id, int ret) "%s, 
> > section_id %u -> %d"
> >  savevm_state_begin(void) ""
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK