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* [Qemu-devel] [PATCH] Introduce "xen-load-devices-state"
@ 2016-03-10 10:23 Changlong Xie
  2016-03-10 20:31 ` Eric Blake
  0 siblings, 1 reply; 4+ messages in thread
From: Changlong Xie @ 2016-03-10 10:23 UTC (permalink / raw)
  To: qemu devel, Juan Quintela, Amit Shah, Eric Blake,
	Markus Armbruster
  Cc: Dr. David Alan Gilbert, zhanghailiang

From: Wen Congyang <wency@cn.fujitsu.com>

Introduce a "xen-load-devices-state" QAPI command that can be used to load
the state of all devices, but not the RAM or the block devices of the
VM.

We only have hmp commands savevm/loadvm, and qmp commands
xen-save-devices-state.

We use this new command for COLO:
1. suspend both primay vm and secondary vm
2. sync the state
3. resume both primary vm and secondary vm

In such case, we need to update all devices's state in any time.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Changlong Xie <xiecl.fnst@cn.fujitsu.com>
---
 migration/savevm.c | 36 ++++++++++++++++++++++++++++++++++++
 qapi-schema.json   | 18 ++++++++++++++++++
 qmp-commands.hx    | 27 +++++++++++++++++++++++++++
 3 files changed, 81 insertions(+)

diff --git a/migration/savevm.c b/migration/savevm.c
index 96e7db5..aaead12 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -50,6 +50,7 @@
 #include "qemu/iov.h"
 #include "block/snapshot.h"
 #include "block/qapi.h"
+#include "hw/xen/xen.h"
 
 
 #ifndef ETH_P_RARP
@@ -1768,6 +1769,12 @@ qemu_loadvm_section_start_full(QEMUFile *f, MigrationIncomingState *mis)
         return -EINVAL;
     }
 
+    /* Validate if it is a device's state */
+    if (xen_enabled() && se->is_ram) {
+        error_report("loadvm: %s RAM loading not allowed on Xen", idstr);
+        return -EINVAL;
+    }
+
     /* Add entry */
     le = g_malloc0(sizeof(*le));
 
@@ -2077,6 +2084,35 @@ void qmp_xen_save_devices_state(const char *filename, Error **errp)
     }
 }
 
+void qmp_xen_load_devices_state(const char *filename, Error **errp)
+{
+    QEMUFile *f;
+    int saved_vm_running;
+    int ret;
+
+    saved_vm_running = runstate_is_running();
+    vm_stop(RUN_STATE_RESTORE_VM);
+
+    f = qemu_fopen(filename, "rb");
+    if (!f) {
+        error_setg_file_open(errp, errno, filename);
+        goto out;
+    }
+
+    migration_incoming_state_new(f);
+    ret = qemu_loadvm_state(f);
+    qemu_fclose(f);
+    migration_incoming_state_destroy();
+    if (ret < 0) {
+        error_setg(errp, QERR_IO_ERROR);
+    }
+
+out:
+    if (saved_vm_running) {
+        vm_start();
+    }
+}
+
 int load_vmstate(const char *name)
 {
     BlockDriverState *bs, *bs_vm_state;
diff --git a/qapi-schema.json b/qapi-schema.json
index 362c9d8..27416b6 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -4122,3 +4122,21 @@
 ##
 { 'enum': 'ReplayMode',
   'data': [ 'none', 'record', 'play' ] }
+
+##
+# @xen-load-devices-state:
+#
+# Load the state of all devices from file. The RAM and the block devices
+# of the VM are not loaded by this command.
+#
+# @filename: the file to load the state of the devices from as binary
+# data. See xen-save-devices-state.txt for a description of the binary
+# format.
+#
+# Returns: Nothing on success
+#          If @filename cannot be opened, OpenFileFailed
+#          If an I/O error occurs while reading the file, IOError
+#
+# Since: 2.6
+##
+{ 'command': 'xen-load-devices-state', 'data': {'filename': 'str'} }
diff --git a/qmp-commands.hx b/qmp-commands.hx
index b629673..5af24a0 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -587,6 +587,33 @@ Example:
 EQMP
 
     {
+        .name       = "xen-load-devices-state",
+        .args_type  = "filename:F",
+        .mhandler.cmd_new = qmp_marshal_xen_load_devices_state,
+    },
+
+SQMP
+xen-load-devices-state
+-------
+
+Load the state of all devices from file. The RAM and the block devices
+of the VM are not loaded by this command.
+
+Arguments:
+
+- "filename": the file to load the state of the devices from as binary
+data. See xen-save-devices-state.txt for a description of the binary
+format.
+
+Example:
+
+-> { "execute": "xen-load-devices-state",
+     "arguments": { "filename": "/tmp/resume" } }
+<- { "return": {} }
+
+EQMP
+
+    {
         .name       = "xen-set-global-dirty-log",
         .args_type  = "enable:b",
         .mhandler.cmd_new = qmp_marshal_xen_set_global_dirty_log,
-- 
1.9.3

^ permalink raw reply related	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2016-03-11  7:28 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2016-03-10 10:23 [Qemu-devel] [PATCH] Introduce "xen-load-devices-state" Changlong Xie
2016-03-10 20:31 ` Eric Blake
2016-03-11  1:29   ` Changlong Xie
2016-03-11  7:28   ` Markus Armbruster

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