Re: [Qemu-devel] [PATCH 05/10] Rework ram_control_load_hook to hook during block load

["Michael R. Hines" <mrhines@linux.vnet.ibm.com>]

On 04/20/2015 10:57 AM, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
>
> We need the names of RAMBlocks as they're loaded for RDMA,
> reuse an existing QEMUFile hook with some small mods.
>
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
>   arch_init.c                   |  4 +++-
>   include/migration/migration.h |  2 +-
>   include/migration/qemu-file.h | 14 +++++++++-----
>   migration/qemu-file.c         |  8 ++++----
>   migration/rdma.c              | 28 ++++++++++++++++++++++------
>   trace-events                  |  2 +-
>   6 files changed, 40 insertions(+), 18 deletions(-)
>
> diff --git a/arch_init.c b/arch_init.c
> index 4c8fcee..6c0b355 100644
> --- a/arch_init.c
> +++ b/arch_init.c
> @@ -1164,6 +1164,8 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
>                                   error_report_err(local_err);
>                               }
>                           }
> +                        ram_control_load_hook(f, RAM_CONTROL_BLOCK_REG,
> +                                              block->idstr);
>                           break;
>                       }
>                   }
> @@ -1215,7 +1217,7 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
>               break;
>           default:
>               if (flags & RAM_SAVE_FLAG_HOOK) {
> -                ram_control_load_hook(f, flags);
> +                ram_control_load_hook(f, RAM_CONTROL_HOOK, NULL);
>               } else {
>                   error_report("Unknown combination of migration flags: %#x",
>                                flags);
> diff --git a/include/migration/migration.h b/include/migration/migration.h
> index bf09968..3c2f91a 100644
> --- a/include/migration/migration.h
> +++ b/include/migration/migration.h
> @@ -154,7 +154,7 @@ int64_t xbzrle_cache_resize(int64_t new_size);
>
>   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);
> +void ram_control_load_hook(QEMUFile *f, uint64_t flags, void *data);
>
>   /* Whenever this is found in the data stream, the flags
>    * will be passed to ram_control_load_hook in the incoming-migration
> diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
> index 745a850..a3ceb3b 100644
> --- a/include/migration/qemu-file.h
> +++ b/include/migration/qemu-file.h
> @@ -63,16 +63,20 @@ typedef ssize_t (QEMUFileWritevBufferFunc)(void *opaque, struct iovec *iov,
>   /*
>    * This function provides hooks around different
>    * stages of RAM migration.
> + * 'opaque' is the backend specific data in QEMUFile
> + * 'data' is call specific data associated with the 'flags' value
>    */

What data is this exactly?

> -typedef int (QEMURamHookFunc)(QEMUFile *f, void *opaque, uint64_t flags);
> +typedef int (QEMURamHookFunc)(QEMUFile *f, void *opaque, uint64_t flags,
> +                              void *data);
>
>   /*
>    * 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
> +#define RAM_CONTROL_SETUP     0
> +#define RAM_CONTROL_ROUND     1
> +#define RAM_CONTROL_HOOK      2
> +#define RAM_CONTROL_FINISH    3
> +#define RAM_CONTROL_BLOCK_REG 4
>
>   /*
>    * This function allows override of where the RAM page
> diff --git a/migration/qemu-file.c b/migration/qemu-file.c
> index 1a4f986..4986e05 100644
> --- a/migration/qemu-file.c
> +++ b/migration/qemu-file.c
> @@ -127,7 +127,7 @@ 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);
> +        ret = f->ops->before_ram_iterate(f, f->opaque, flags, NULL);
>           if (ret < 0) {
>               qemu_file_set_error(f, ret);
>           }
> @@ -139,19 +139,19 @@ 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);
> +        ret = f->ops->after_ram_iterate(f, f->opaque, flags, NULL);
>           if (ret < 0) {
>               qemu_file_set_error(f, ret);
>           }
>       }
>   }
>
> -void ram_control_load_hook(QEMUFile *f, uint64_t flags)
> +void ram_control_load_hook(QEMUFile *f, uint64_t flags, void *data)
>   {
>       int ret = -EINVAL;
>
>       if (f->ops->hook_ram_load) {
> -        ret = f->ops->hook_ram_load(f, f->opaque, flags);
> +        ret = f->ops->hook_ram_load(f, f->opaque, flags, data);
>           if (ret < 0) {
>               qemu_file_set_error(f, ret);
>           }
> diff --git a/migration/rdma.c b/migration/rdma.c
> index 2c0d11b..e43fae4 100644
> --- a/migration/rdma.c
> +++ b/migration/rdma.c
> @@ -2906,8 +2906,7 @@ err_rdma_dest_wait:
>    *
>    * Keep doing this until the source tells us to stop.
>    */
> -static int qemu_rdma_registration_handle(QEMUFile *f, void *opaque,
> -                                         uint64_t flags)
> +static int qemu_rdma_registration_handle(QEMUFile *f, void *opaque)
>   {
>       RDMAControlHeader reg_resp = { .len = sizeof(RDMARegisterResult),
>                                  .type = RDMA_CONTROL_REGISTER_RESULT,
> @@ -2937,7 +2936,7 @@ static int qemu_rdma_registration_handle(QEMUFile *f, void *opaque,
>       CHECK_ERROR_STATE();
>
>       do {
> -        trace_qemu_rdma_registration_handle_wait(flags);
> +        trace_qemu_rdma_registration_handle_wait();
>
>           ret = qemu_rdma_exchange_recv(rdma, &head, RDMA_CONTROL_NONE);
>
> @@ -3125,8 +3124,25 @@ out:
>       return ret;
>   }
>
> +static int rdma_load_hook(QEMUFile *f, void *opaque, uint64_t flags, void *data)
> +{
> +    switch (flags) {
> +    case RAM_CONTROL_BLOCK_REG:
> +        /* TODO A later patch */
> +        return -1;
> +        break;
> +
> +    case RAM_CONTROL_HOOK:
> +        return qemu_rdma_registration_handle(f, opaque);
> +
> +    default:
> +        /* Shouldn't be called with any other values */
> +        abort();
> +    }
> +}
> +

Rename this to qemu_rdma_load_hook()

>   static int qemu_rdma_registration_start(QEMUFile *f, void *opaque,
> -                                        uint64_t flags)
> +                                        uint64_t flags, void *data)
>   {
>       QEMUFileRDMA *rfile = opaque;
>       RDMAContext *rdma = rfile->rdma;
> @@ -3145,7 +3161,7 @@ static int qemu_rdma_registration_start(QEMUFile *f, void *opaque,
>    * First, flush writes, if any.
>    */
>   static int qemu_rdma_registration_stop(QEMUFile *f, void *opaque,
> -                                       uint64_t flags)
> +                                       uint64_t flags, void *data)
>   {
>       Error *local_err = NULL, **errp = &local_err;
>       QEMUFileRDMA *rfile = opaque;
> @@ -3267,7 +3283,7 @@ static const QEMUFileOps rdma_read_ops = {
>       .get_buffer    = qemu_rdma_get_buffer,
>       .get_fd        = qemu_rdma_get_fd,
>       .close         = qemu_rdma_close,
> -    .hook_ram_load = qemu_rdma_registration_handle,
> +    .hook_ram_load = rdma_load_hook,
>   };
>
>   static const QEMUFileOps rdma_write_ops = {
> diff --git a/trace-events b/trace-events
> index 07f15da..baf8647 100644
> --- a/trace-events
> +++ b/trace-events
> @@ -1416,7 +1416,7 @@ qemu_rdma_registration_handle_register_rkey(int rkey) "%x"
>   qemu_rdma_registration_handle_unregister(int requests) "%d requests"
>   qemu_rdma_registration_handle_unregister_loop(int count, int index, uint64_t chunk) "Unregistration request (%d): index %d, chunk %" PRIu64
>   qemu_rdma_registration_handle_unregister_success(uint64_t chunk) "%" PRIu64
> -qemu_rdma_registration_handle_wait(uint64_t flags) "Waiting for next request %" PRIu64
> +qemu_rdma_registration_handle_wait(void) ""
>   qemu_rdma_registration_start(uint64_t flags) "%" PRIu64
>   qemu_rdma_registration_stop(uint64_t flags) "%" PRIu64
>   qemu_rdma_registration_stop_ram(void) ""