[Qemu-devel] [PULL 06/28] Rework ram_control_load_hook to hook during block load

[Juan Quintela <quintela@redhat.com>]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

We need the names of RAMBlocks as they're loaded for RDMA,
reuse a slightly modified ram_control_load_hook:
  a) Pass a 'data' parameter to use for the name in the block-reg
     case
  b) Only some hook types now require the presence of a hook function.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 include/migration/migration.h |  2 +-
 include/migration/qemu-file.h | 14 +++++++++-----
 migration/qemu-file.c         | 16 +++++++++++-----
 migration/ram.c               |  4 +++-
 migration/rdma.c              | 28 ++++++++++++++++++++++------
 trace-events                  |  2 +-
 6 files changed, 47 insertions(+), 19 deletions(-)

diff --git a/include/migration/migration.h b/include/migration/migration.h
index 9387c8c..afba233 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -179,7 +179,7 @@ int migrate_decompress_threads(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);
+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 4f67d79..ea49f33 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
  */
-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 557c1c1..6bb3dc1 100644
--- a/migration/qemu-file.c
+++ b/migration/qemu-file.c
@@ -129,7 +129,7 @@ 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);
         }
@@ -141,24 +141,30 @@ 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);
         }
     } else {
-        qemu_file_set_error(f, ret);
+        /*
+         * Hook is a hook specifically requested by the source sending a flag
+         * that expects there to be a hook on the destination.
+         */
+        if (flags == RAM_CONTROL_HOOK) {
+            qemu_file_set_error(f, ret);
+        }
     }
 }

diff --git a/migration/ram.c b/migration/ram.c
index 57368e1..644f52a 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1477,6 +1477,8 @@ 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;
                     }
                 }
@@ -1545,7 +1547,7 @@ 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/migration/rdma.c b/migration/rdma.c
index d489012..fab736e 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -2913,8 +2913,7 @@ 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,
@@ -2944,7 +2943,7 @@ 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);

@@ -3132,8 +3131,25 @@ 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 0;
+        break;
+
+    case RAM_CONTROL_HOOK:
+        return qemu_rdma_registration_handle(f, opaque);
+
+    default:
+        /* Shouldn't be called with any other values */
+        abort();
+    }
+}
+
 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;
@@ -3152,7 +3168,7 @@ 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;
@@ -3274,7 +3290,7 @@ 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 b29d8af..f1b94d6 100644
--- a/trace-events
+++ b/trace-events
@@ -1439,7 +1439,7 @@ 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) ""
-- 
2.4.3