Re: [Qemu-devel] [PATCH 2/5] ivshmem: use migration blockers to prevent live migration in peer mode (v2)

[Michael Roth <mdroth@linux.vnet.ibm.com>]

On 11/14/2011 03:09 PM, Anthony Liguori wrote:
> Now when you try to migrate with ivshmem, you get a proper QMP error:
>
> (qemu) migrate tcp:localhost:1025
> Migration is disabled when using feature 'peer mode' in device 'ivshmem'
> (qemu)
>
> Signed-off-by: Anthony Liguori<aliguori@us.ibm.com>
> ---
> v1 ->  v2
>   - remove register_device_unmigratable as ivshmem was the only user
> ---
>   hw/ivshmem.c |   12 +-
>   qerror.c     |    4 +
>   qerror.h     |    3 +
>   savevm.c     |   25 ---
>   vmstate.h    |  610 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>   5 files changed, 628 insertions(+), 26 deletions(-)
>   create mode 100644 vmstate.h
>
> diff --git a/hw/ivshmem.c b/hw/ivshmem.c
> index 242fbea..a3a0e98 100644
> --- a/hw/ivshmem.c
> +++ b/hw/ivshmem.c
> @@ -18,6 +18,8 @@
>   #include "pci.h"
>   #include "msix.h"
>   #include "kvm.h"
> +#include "migration.h"
> +#include "qerror.h"
>
>   #include<sys/mman.h>
>   #include<sys/types.h>
> @@ -78,6 +80,8 @@ typedef struct IVShmemState {
>       uint32_t features;
>       EventfdEntry *eventfd_table;
>
> +    Error *migration_blocker;
> +
>       char * shmobj;
>       char * sizearg;
>       char * role;
> @@ -646,7 +650,8 @@ static int pci_ivshmem_init(PCIDevice *dev)
>       }
>
>       if (s->role_val == IVSHMEM_PEER) {
> -        register_device_unmigratable(&s->dev.qdev, "ivshmem", s);
> +        error_set(&s->migration_blocker, QERR_DEVICE_FEATURE_BLOCKS_MIGRATION, "ivshmem", "peer mode");
> +        migrate_add_blocker(s->migration_blocker);
>       }
>
>       pci_conf = s->dev.config;
> @@ -741,6 +746,11 @@ static int pci_ivshmem_uninit(PCIDevice *dev)
>   {
>       IVShmemState *s = DO_UPCAST(IVShmemState, dev, dev);
>
> +    if (s->migration_blocker) {
> +        migrate_del_blocker(s->migration_blocker);
> +        error_free(s->migration_blocker);
> +    }
> +
>       memory_region_destroy(&s->ivshmem_mmio);
>       memory_region_del_subregion(&s->bar,&s->ivshmem);
>       memory_region_destroy(&s->ivshmem);
> diff --git a/qerror.c b/qerror.c
> index 4b48b39..8e30e2d 100644
> --- a/qerror.c
> +++ b/qerror.c
> @@ -73,6 +73,10 @@ static const QErrorStringTable qerror_table[] = {
>           .desc      = "Device '%(device)' is in use",
>       },
>       {
> +        .error_fmt = QERR_DEVICE_FEATURE_BLOCKS_MIGRATION,
> +        .desc      = "Migration is disabled when using feature '%(feature)' in device '%(device)'",
> +    },
> +    {
>           .error_fmt = QERR_DEVICE_LOCKED,
>           .desc      = "Device '%(device)' is locked",
>       },
> diff --git a/qerror.h b/qerror.h
> index d4bfcfd..7e2eebf 100644
> --- a/qerror.h
> +++ b/qerror.h
> @@ -72,6 +72,9 @@ QError *qobject_to_qerror(const QObject *obj);
>   #define QERR_DEVICE_IN_USE \
>       "{ 'class': 'DeviceInUse', 'data': { 'device': %s } }"
>
> +#define QERR_DEVICE_FEATURE_BLOCKS_MIGRATION \
> +    "{ 'class': 'DeviceFeatureBlocksMigration', 'data': { 'device': %s, 'feature': %s } }"
> +
>   #define QERR_DEVICE_LOCKED \
>       "{ 'class': 'DeviceLocked', 'data': { 'device': %s } }"
>
> diff --git a/savevm.c b/savevm.c
> index bee16c0..f53cd4c 100644
> --- a/savevm.c
> +++ b/savevm.c
> @@ -1255,31 +1255,6 @@ void unregister_savevm(DeviceState *dev, const char *idstr, void *opaque)
>       }
>   }
>
> -/* mark a device as not to be migrated, that is the device should be
> -   unplugged before migration */
> -void register_device_unmigratable(DeviceState *dev, const char *idstr,
> -                                                            void *opaque)
> -{
> -    SaveStateEntry *se;
> -    char id[256] = "";
> -
> -    if (dev&&  dev->parent_bus&&  dev->parent_bus->info->get_dev_path) {
> -        char *path = dev->parent_bus->info->get_dev_path(dev);
> -        if (path) {
> -            pstrcpy(id, sizeof(id), path);
> -            pstrcat(id, sizeof(id), "/");
> -            g_free(path);
> -        }
> -    }
> -    pstrcat(id, sizeof(id), idstr);
> -
> -    QTAILQ_FOREACH(se,&savevm_handlers, entry) {
> -        if (strcmp(se->idstr, id) == 0&&  se->opaque == opaque) {
> -            se->no_migrate = 1;
> -        }
> -    }
> -}
> -
>   int vmstate_register_with_alias_id(DeviceState *dev, int instance_id,
>                                      const VMStateDescription *vmsd,
>                                      void *opaque, int alias_id,
> diff --git a/vmstate.h b/vmstate.h
> new file mode 100644
> index 0000000..9ea4783
> --- /dev/null
> +++ b/vmstate.h
> @@ -0,0 +1,610 @@
> +/*
> + * QEMU migration/snapshot declarations
> + *

I take it these were meant for a separate series? We still have these 
defs in hw/hw.h