Re: [Qemu-devel] [PATCH 2/2] migration: Poison ramblock loops in migration

[Cédric Le Goater]

On 06/05/2018 06:25 PM, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <address@hidden>
> 
> The migration code should be using the
>   RAMBLOCK_FOREACH_MIGRATABLE and qemu_ram_foreach_block_migratable
> not the all-block versions;  poison them so that we can't accidentally
> use them.
> 
> Signed-off-by: Dr. David Alan Gilbert <address@hidden>

Reviewed-by: Cédric Le Goater <address@hidden> 

Thanks,

C.


> ---
>  include/exec/ramlist.h | 4 +++-
>  migration/migration.h  | 3 +++
>  migration/ram.c        | 4 +++-
>  3 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/include/exec/ramlist.h b/include/exec/ramlist.h
> index 2e2ac6cb99..bc4faa1b00 100644
> --- a/include/exec/ramlist.h
> +++ b/include/exec/ramlist.h
> @@ -56,8 +56,10 @@ typedef struct RAMList {
>  extern RAMList ram_list;
>  
>  /* Should be holding either ram_list.mutex, or the RCU lock. */
> -#define  RAMBLOCK_FOREACH(block)  \
> +#define  INTERNAL_RAMBLOCK_FOREACH(block)  \
>      QLIST_FOREACH_RCU(block, &ram_list.blocks, next)
> +/* Never use the INTERNAL_ version except for defining other macros */
> +#define RAMBLOCK_FOREACH(block) INTERNAL_RAMBLOCK_FOREACH(block)
>  
>  void qemu_mutex_lock_ramlist(void);
>  void qemu_mutex_unlock_ramlist(void);
> diff --git a/migration/migration.h b/migration/migration.h
> index 5af57d616c..31d3ed12dc 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -284,4 +284,7 @@ void migrate_send_rp_resume_ack(MigrationIncomingState 
> *mis, uint32_t value);
>  void dirty_bitmap_mig_before_vm_start(void);
>  void init_dirty_bitmap_incoming_migration(void);
>  
> +#define qemu_ram_foreach_block \
> +  #warning "Use qemu_ram_foreach_block_migratable in migration code"
> +
>  #endif
> diff --git a/migration/ram.c b/migration/ram.c
> index a7807cea84..e0d19305ee 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -159,9 +159,11 @@ out:
>  
>  /* Should be holding either ram_list.mutex, or the RCU lock. */
>  #define RAMBLOCK_FOREACH_MIGRATABLE(block)             \
> -    RAMBLOCK_FOREACH(block)                            \
> +    INTERNAL_RAMBLOCK_FOREACH(block)                   \
>          if (!qemu_ram_is_migratable(block)) {} else
>  
> +#undef RAMBLOCK_FOREACH
> +
>  static void ramblock_recv_map_init(void)
>  {
>      RAMBlock *rb;
>