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authorAnton Nefedov <anton.nefedov@virtuozzo.com>2017-07-06 15:08:50 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2017-07-14 11:04:33 +0200
commit7bb86085e61befc95551055e26645cb23c3f0b86 (patch)
treed6727fbff8b5d996a0d1325ec04bfe14d17f3afa /qapi-schema.json
parent81517ba37a6cec59f92396b4722861868eb0a500 (diff)
downloadqemu-arm-7bb86085e61befc95551055e26645cb23c3f0b86.tar.gz
char: chardevice hotswap
This patch adds a possibility to change a char device without a frontend removal. Ideally, it would have to happen transparently to a frontend, i.e. frontend would continue its regular operation. However, backends are not stateless and are set up by the frontends via qemu_chr_fe_<> functions, and it's not (generally) possible to replay that setup entirely in a backend code, as different chardevs respond to the setup calls differently, so do frontends work differently basing on those setup responses. Moreover, some frontend can generally get and save the backend pointer (qemu_chr_fe_get_driver()), and it will become invalid after backend change. So, a frontend which would like to support chardev hotswap has to register a "backend change" handler, and redo its backend setup there. Signed-off-by: Anton Nefedov <anton.nefedov@virtuozzo.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <1499342940-56739-4-git-send-email-anton.nefedov@virtuozzo.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'qapi-schema.json')
-rw-r--r--qapi-schema.json40
1 files changed, 40 insertions, 0 deletions
diff --git a/qapi-schema.json b/qapi-schema.json
index 485767f1ab..ab438ead70 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -5090,6 +5090,46 @@
'returns': 'ChardevReturn' }
##
+# @chardev-change:
+#
+# Change a character device backend
+#
+# @id: the chardev's ID, must exist
+# @backend: new backend type and parameters
+#
+# Returns: ChardevReturn.
+#
+# Since: 2.10
+#
+# Example:
+#
+# -> { "execute" : "chardev-change",
+# "arguments" : { "id" : "baz",
+# "backend" : { "type" : "pty", "data" : {} } } }
+# <- { "return": { "pty" : "/dev/pty/42" } }
+#
+# -> {"execute" : "chardev-change",
+# "arguments" : {
+# "id" : "charchannel2",
+# "backend" : {
+# "type" : "socket",
+# "data" : {
+# "addr" : {
+# "type" : "unix" ,
+# "data" : {
+# "path" : "/tmp/charchannel2.socket"
+# }
+# },
+# "server" : true,
+# "wait" : false }}}}
+# <- {"return": {}}
+#
+##
+{ 'command': 'chardev-change', 'data': {'id' : 'str',
+ 'backend' : 'ChardevBackend' },
+ 'returns': 'ChardevReturn' }
+
+##
# @chardev-remove:
#
# Remove a character device backend