Xen devel - Jul 2012 - [PATCH 1/4] QMP, Introduce set-global-dirty-log command.

This command is used during a migration of a guest under Xen. It calls
memory_global_dirty_log_start or memory_global_dirty_log_stop according to the
argument pass to the command.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
---
 qapi-schema.json |   13 +++++++++++++
 qmp-commands.hx  |   24 ++++++++++++++++++++++++
 xen-all.c        |   15 +++++++++++++++
 xen-stub.c       |    5 +++++
 4 files changed, 57 insertions(+), 0 deletions(-)

diff --git a/qapi-schema.json b/qapi-schema.json
index 1ab5dbd..e8d17b5 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1765,6 +1765,19 @@
 { ''command'': ''xen-save-devices-state'',
''data'': {''filename'':
''str''} }
 
 ##
+# @xen-set-global-dirty-log
+#
+# Enable or disable the global dirty log mode.
+#
+# @enable: true to enable, false to disable.
+#
+# Returns: nothing
+#
+# Since: 1.2
+##
+{ ''command'': ''xen-set-global-dirty-log'',
''data'': { ''enable'': ''bool''
} }
+
+##
 # @device_del:
 #
 # Remove a device from a guest
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 2e1a38e..c92decd 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -468,6 +468,30 @@ Example:
 EQMP
 
     {
+        .name       = "xen-set-global-dirty-log",
+        .args_type  = "enable:b",
+        .mhandler.cmd_new = qmp_marshal_input_xen_set_global_dirty_log,
+    },
+
+SQMP
+xen-set-global-dirty-log
+-------
+
+Enable or disable the global dirty log mode.
+
+Arguments:
+
+- "enable": Enable it or disable it.
+
+Example:
+
+-> { "execute": "xen-set-global-dirty-log",
+     "arguments": { "enable": true } }
+<- { "return": {} }
+
+EQMP
+
+    {
         .name       = "migrate",
         .args_type  = "detach:-d,blk:-b,inc:-i,uri:s",
         .mhandler.cmd_new = qmp_marshal_input_migrate,
diff --git a/xen-all.c b/xen-all.c
index 59f2323..8995d43 100644
--- a/xen-all.c
+++ b/xen-all.c
@@ -14,6 +14,7 @@
 #include "hw/pc.h"
 #include "hw/xen_common.h"
 #include "hw/xen_backend.h"
+#include "qmp-commands.h"
 
 #include "range.h"
 #include "xen-mapcache.h"
@@ -36,6 +37,7 @@
 
 static MemoryRegion ram_memory, ram_640k, ram_lo, ram_hi;
 static MemoryRegion *framebuffer;
+static bool xen_in_migration;
 
 /* Compatibility with older version */
 #if __XEN_LATEST_INTERFACE_VERSION__ < 0x0003020a
@@ -552,10 +554,14 @@ static void xen_log_sync(MemoryListener *listener,
MemoryRegionSection *section)
 
 static void xen_log_global_start(MemoryListener *listener)
 {
+    if (xen_enabled()) {
+        xen_in_migration = true;
+    }
 }
 
 static void xen_log_global_stop(MemoryListener *listener)
 {
+    xen_in_migration = false;
 }
 
 static void xen_eventfd_add(MemoryListener *listener,
@@ -586,6 +592,15 @@ static MemoryListener xen_memory_listener = {
     .priority = 10,
 };
 
+void qmp_xen_set_global_dirty_log(bool enable, Error **errp)
+{
+    if (enable) {
+        memory_global_dirty_log_start();
+    } else {
+        memory_global_dirty_log_stop();
+    }
+}
+
 /* VCPU Operations, MMIO, IO ring ... */
 
 static void xen_reset_vcpu(void *opaque)
diff --git a/xen-stub.c b/xen-stub.c
index 8ff2b79..5e66ba8 100644
--- a/xen-stub.c
+++ b/xen-stub.c
@@ -11,6 +11,7 @@
 #include "qemu-common.h"
 #include "hw/xen.h"
 #include "memory.h"
+#include "qmp-commands.h"
 
 void xenstore_store_pv_console_info(int i, CharDriverState *chr)
 {
@@ -54,3 +55,7 @@ int xen_init(void)
 void xen_register_framebuffer(MemoryRegion *mr)
 {
 }
+
+void qmp_xen_set_global_dirty_log(bool enable, Error **errp)
+{
+}
-- 
Anthony PERARD

On 07/17/2012 04:30 PM, Anthony PERARD wrote:
> This command is used during a migration of a guest under Xen. It calls
> memory_global_dirty_log_start or memory_global_dirty_log_stop according to
the
> argument pass to the command.
Is the command truly needed?  Can''t it come from the xen library you
link to?


-- 
error compiling committee.c: too many arguments to function

On Tue, 17 Jul 2012, Avi Kivity wrote:
> On 07/17/2012 04:30 PM, Anthony PERARD wrote:
> > This command is used during a migration of a guest under Xen. It calls
> > memory_global_dirty_log_start or memory_global_dirty_log_stop
according to the
> > argument pass to the command.
> 
> Is the command truly needed?  Can''t it come from the xen library
you
> link to?
I thought that a while ago we decided to use QMP rather than xenstore to
issue Xen commands to QEMU.
The only xenstore stuff left are the PV protocols and few parameters.

Of course we could use xenstore to issue commands again, but it goes
against the last year and an half of development :-)

On 07/17/2012 08:58 PM, Stefano Stabellini wrote:
> On Tue, 17 Jul 2012, Avi Kivity wrote:
>> On 07/17/2012 04:30 PM, Anthony PERARD wrote:
>> > This command is used during a migration of a guest under Xen. It
calls
>> > memory_global_dirty_log_start or memory_global_dirty_log_stop
according to the
>> > argument pass to the command.
>> 
>> Is the command truly needed?  Can''t it come from the xen
library you
>> link to?
> 
> I thought that a while ago we decided to use QMP rather than xenstore to
> issue Xen commands to QEMU.
> The only xenstore stuff left are the PV protocols and few parameters.
> 
> Of course we could use xenstore to issue commands again, but it goes
> against the last year and an half of development :-)
This particular command is weird.  You enable dirty logging via an
external interface, but all output goes through the internal interface.
 It doesn''t make much sense.

But let''s not reopen the issue, if it was decided to go with qmp
command
for those things then so be it.

-- 
error compiling committee.c: too many arguments to function