migration: Change zero_copy_send from migration parameter to migration capability

When originally implemented, zero_copy_send was designed as a Migration
paramenter.

But taking into account how is that supposed to work, and how
the difference between a capability and a parameter, it only makes sense
that zero-copy-send would work better as a capability.

Taking into account how recently the change got merged, it was decided
that it's still time to make it right, and convert zero_copy_send into
a Migration capability.

Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
  dgilbert: always define the capability, even on non-Linux but error if
set; avoids build problems with the capability

1 files changed, 9 insertions, 24 deletions

diff --git a/qapi/migration.json b/qapi/migration.json
index 6130cd9fae..7102e474a6 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -461,6 +461,13 @@
 #                       procedure starts. The VM RAM is saved with running VM.
 #                       (since 6.0)
 #
+# @zero-copy-send: Controls behavior on sending memory pages on migration.
+#                  When true, enables a zero-copy mechanism for sending
+#                  memory pages, if host supports it.
+#                  Requires that QEMU be permitted to use locked memory
+#                  for guest RAM pages.
+#                  (since 7.1)
+#
 # Features:
 # @unstable: Members @x-colo and @x-ignore-shared are experimental.
 #
@@ -474,7 +481,8 @@
            'block', 'return-path', 'pause-before-switchover', 'multifd',
            'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate',
            { 'name': 'x-ignore-shared', 'features': [ 'unstable' ] },
-           'validate-uuid', 'background-snapshot'] }
+           'validate-uuid', 'background-snapshot',
+           'zero-copy-send'] }
 
 ##
 # @MigrationCapabilityStatus:
@@ -738,12 +746,6 @@
 #                      will consume more CPU.
 #                      Defaults to 1. (Since 5.0)
 #
-# @zero-copy-send: Controls behavior on sending memory pages on migration.
-#                  When true, enables a zero-copy mechanism for sending
-#                  memory pages, if host supports it.
-#                  Requires that QEMU be permitted to use locked memory
-#                  for guest RAM pages.
-#                  Defaults to false. (Since 7.1)
 #
 # @block-bitmap-mapping: Maps block nodes and bitmaps on them to
 #                        aliases for the purpose of dirty bitmap migration.  Such
@@ -784,7 +786,6 @@
            'xbzrle-cache-size', 'max-postcopy-bandwidth',
            'max-cpu-throttle', 'multifd-compression',
            'multifd-zlib-level' ,'multifd-zstd-level',
-           { 'name': 'zero-copy-send', 'if' : 'CONFIG_LINUX'},
            'block-bitmap-mapping' ] }
 
 ##
@@ -911,13 +912,6 @@
 #                      will consume more CPU.
 #                      Defaults to 1. (Since 5.0)
 #
-# @zero-copy-send: Controls behavior on sending memory pages on migration.
-#                  When true, enables a zero-copy mechanism for sending
-#                  memory pages, if host supports it.
-#                  Requires that QEMU be permitted to use locked memory
-#                  for guest RAM pages.
-#                  Defaults to false. (Since 7.1)
-#
 # @block-bitmap-mapping: Maps block nodes and bitmaps on them to
 #                        aliases for the purpose of dirty bitmap migration.  Such
 #                        aliases may for example be the corresponding names on the
@@ -972,7 +966,6 @@
             '*multifd-compression': 'MultiFDCompression',
             '*multifd-zlib-level': 'uint8',
             '*multifd-zstd-level': 'uint8',
-            '*zero-copy-send': { 'type': 'bool', 'if': 'CONFIG_LINUX' },
             '*block-bitmap-mapping': [ 'BitmapMigrationNodeAlias' ] } }
 
 ##
@@ -1119,13 +1112,6 @@
 #                      will consume more CPU.
 #                      Defaults to 1. (Since 5.0)
 #
-# @zero-copy-send: Controls behavior on sending memory pages on migration.
-#                  When true, enables a zero-copy mechanism for sending
-#                  memory pages, if host supports it.
-#                  Requires that QEMU be permitted to use locked memory
-#                  for guest RAM pages.
-#                  Defaults to false. (Since 7.1)
-#
 # @block-bitmap-mapping: Maps block nodes and bitmaps on them to
 #                        aliases for the purpose of dirty bitmap migration.  Such
 #                        aliases may for example be the corresponding names on the
@@ -1178,7 +1164,6 @@
             '*multifd-compression': 'MultiFDCompression',
             '*multifd-zlib-level': 'uint8',
             '*multifd-zstd-level': 'uint8',
-            '*zero-copy-send': { 'type': 'bool', 'if': 'CONFIG_LINUX' },
             '*block-bitmap-mapping': [ 'BitmapMigrationNodeAlias' ] } }
 
 ##