* [PATCH 1/1] migration/cpr: Add HMP support for cpr-transfer
@ 2026-06-21 7:26 Dongli Zhang
2026-06-23 12:24 ` Dr. David Alan Gilbert
2026-06-24 15:26 ` Fabiano Rosas
0 siblings, 2 replies; 4+ messages in thread
From: Dongli Zhang @ 2026-06-21 7:26 UTC (permalink / raw)
To: qemu-devel; +Cc: dave, peterx, farosas, maciej.szmigiero, mark.kanda, bchaney
Currently the cpr-transfer source QEMU instance cannot be driven entirely
via HMP. The source must use QMP in order to specify both the
main migration channel and the CPR channel.
Extend the HMP migrate command with an optional CPR channel URI. When the
migration mode is cpr-transfer, HMP uses this URI to build a
CPR MigrationChannel in addition to the main migration channel. The new
argument is rejected unless the migration mode is cpr-transfer, so existing
HMP migrate usage is unchanged.
For example, source QEMU HMP commands can be something like below. The
"unix:/tmp/cpr.sock" is for CPR URI.
(qemu) migrate_set_parameter mode cpr-transfer
(qemu) migrate tcp:0:50002 unix:/tmp/cpr.sock
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
---
hmp-commands.hx | 11 +++++++----
migration/migration-hmp-cmds.c | 18 ++++++++++++++++++
2 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 7ae2468a3d..021e51b142 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -928,16 +928,17 @@ ERST
{
.name = "migrate",
- .args_type = "detach:-d,resume:-r,uri:s",
- .params = "[-d] [-r] uri",
+ .args_type = "detach:-d,resume:-r,uri:s,uri-cpr:s?",
+ .params = "[-d] [-r] uri [uri-cpr]",
.help = "migrate to URI (using -d to not wait for completion)"
- "\n\t\t\t -r to resume a paused postcopy migration",
+ "\n\t\t\t -r to resume a paused postcopy migration"
+ "\n\t\t\t uri-cpr specifies CPR URI for cpr-transfer mode",
.cmd = hmp_migrate,
},
SRST
-``migrate [-d] [-r]`` *uri*
+``migrate [-d] [-r]`` *uri* [*uri-cpr*]
Migrate the VM to *uri*.
``-d``
@@ -945,6 +946,8 @@ SRST
query an ongoing migration process, use "info migrate".
``-r``
Resume a paused postcopy migration.
+ ``uri-cpr``
+ Specify CPR URI for cpr-transfer mode. It must be a UNIX domain socket.
ERST
{
diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
index 8b385f560e..42ca652bb3 100644
--- a/migration/migration-hmp-cmds.c
+++ b/migration/migration-hmp-cmds.c
@@ -836,9 +836,11 @@ void hmp_migrate(Monitor *mon, const QDict *qdict)
bool detach = qdict_get_try_bool(qdict, "detach", false);
bool resume = qdict_get_try_bool(qdict, "resume", false);
const char *uri = qdict_get_str(qdict, "uri");
+ const char *uri_cpr = qdict_get_try_str(qdict, "uri-cpr");
Error *err = NULL;
g_autoptr(MigrationChannelList) caps = NULL;
g_autoptr(MigrationChannel) channel = NULL;
+ g_autoptr(MigrationChannel) channel_cpr = NULL;
if (!migrate_uri_parse(uri, &channel, &err)) {
hmp_handle_error(mon, err);
@@ -846,6 +848,22 @@ void hmp_migrate(Monitor *mon, const QDict *qdict)
}
QAPI_LIST_PREPEND(caps, g_steal_pointer(&channel));
+ if (uri_cpr) {
+ if (migrate_mode() != MIG_MODE_CPR_TRANSFER) {
+ error_setg(&err, "uri-cpr requires cpr-transfer mode");
+ hmp_handle_error(mon, err);
+ return;
+ }
+
+ if (!migrate_uri_parse(uri_cpr, &channel_cpr, &err)) {
+ hmp_handle_error(mon, err);
+ return;
+ }
+
+ channel_cpr->channel_type = MIGRATION_CHANNEL_TYPE_CPR;
+ QAPI_LIST_PREPEND(caps, g_steal_pointer(&channel_cpr));
+ }
+
qmp_migrate(NULL, true, caps, true, resume, &err);
if (hmp_handle_error(mon, err)) {
return;
--
2.43.7
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH 1/1] migration/cpr: Add HMP support for cpr-transfer
2026-06-21 7:26 [PATCH 1/1] migration/cpr: Add HMP support for cpr-transfer Dongli Zhang
@ 2026-06-23 12:24 ` Dr. David Alan Gilbert
2026-06-23 13:03 ` Peter Xu
2026-06-24 15:26 ` Fabiano Rosas
1 sibling, 1 reply; 4+ messages in thread
From: Dr. David Alan Gilbert @ 2026-06-23 12:24 UTC (permalink / raw)
To: Dongli Zhang
Cc: qemu-devel, peterx, farosas, maciej.szmigiero, mark.kanda,
bchaney
* Dongli Zhang (dongli.zhang@oracle.com) wrote:
> Currently the cpr-transfer source QEMU instance cannot be driven entirely
> via HMP. The source must use QMP in order to specify both the
> main migration channel and the CPR channel.
>
> Extend the HMP migrate command with an optional CPR channel URI. When the
> migration mode is cpr-transfer, HMP uses this URI to build a
> CPR MigrationChannel in addition to the main migration channel. The new
> argument is rejected unless the migration mode is cpr-transfer, so existing
> HMP migrate usage is unchanged.
>
> For example, source QEMU HMP commands can be something like below. The
> "unix:/tmp/cpr.sock" is for CPR URI.
>
> (qemu) migrate_set_parameter mode cpr-transfer
> (qemu) migrate tcp:0:50002 unix:/tmp/cpr.sock
>
> Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Yeh this looks OK to me; I don't see a check for if you do:
(qemu) migrate_set_parameter mode cpr-transfer
(qemu) migrate tcp:0:50002
Does that get caught by the qmp_migrate or should you add a check here?
I do have a slight preference for using flag optional parameters rather
than positional, e.g.
migrate -c unix:/tmp/cpr.sock tcp:0:50002
but I wouldn't insist on it.
Dave
> ---
> hmp-commands.hx | 11 +++++++----
> migration/migration-hmp-cmds.c | 18 ++++++++++++++++++
> 2 files changed, 25 insertions(+), 4 deletions(-)
>
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index 7ae2468a3d..021e51b142 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -928,16 +928,17 @@ ERST
>
> {
> .name = "migrate",
> - .args_type = "detach:-d,resume:-r,uri:s",
> - .params = "[-d] [-r] uri",
> + .args_type = "detach:-d,resume:-r,uri:s,uri-cpr:s?",
> + .params = "[-d] [-r] uri [uri-cpr]",
> .help = "migrate to URI (using -d to not wait for completion)"
> - "\n\t\t\t -r to resume a paused postcopy migration",
> + "\n\t\t\t -r to resume a paused postcopy migration"
> + "\n\t\t\t uri-cpr specifies CPR URI for cpr-transfer mode",
> .cmd = hmp_migrate,
> },
>
>
> SRST
> -``migrate [-d] [-r]`` *uri*
> +``migrate [-d] [-r]`` *uri* [*uri-cpr*]
> Migrate the VM to *uri*.
>
> ``-d``
> @@ -945,6 +946,8 @@ SRST
> query an ongoing migration process, use "info migrate".
> ``-r``
> Resume a paused postcopy migration.
> + ``uri-cpr``
> + Specify CPR URI for cpr-transfer mode. It must be a UNIX domain socket.
> ERST
>
> {
> diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
> index 8b385f560e..42ca652bb3 100644
> --- a/migration/migration-hmp-cmds.c
> +++ b/migration/migration-hmp-cmds.c
> @@ -836,9 +836,11 @@ void hmp_migrate(Monitor *mon, const QDict *qdict)
> bool detach = qdict_get_try_bool(qdict, "detach", false);
> bool resume = qdict_get_try_bool(qdict, "resume", false);
> const char *uri = qdict_get_str(qdict, "uri");
> + const char *uri_cpr = qdict_get_try_str(qdict, "uri-cpr");
> Error *err = NULL;
> g_autoptr(MigrationChannelList) caps = NULL;
> g_autoptr(MigrationChannel) channel = NULL;
> + g_autoptr(MigrationChannel) channel_cpr = NULL;
>
> if (!migrate_uri_parse(uri, &channel, &err)) {
> hmp_handle_error(mon, err);
> @@ -846,6 +848,22 @@ void hmp_migrate(Monitor *mon, const QDict *qdict)
> }
> QAPI_LIST_PREPEND(caps, g_steal_pointer(&channel));
>
> + if (uri_cpr) {
> + if (migrate_mode() != MIG_MODE_CPR_TRANSFER) {
> + error_setg(&err, "uri-cpr requires cpr-transfer mode");
> + hmp_handle_error(mon, err);
> + return;
> + }
> +
> + if (!migrate_uri_parse(uri_cpr, &channel_cpr, &err)) {
> + hmp_handle_error(mon, err);
> + return;
> + }
> +
> + channel_cpr->channel_type = MIGRATION_CHANNEL_TYPE_CPR;
> + QAPI_LIST_PREPEND(caps, g_steal_pointer(&channel_cpr));
> + }
> +
> qmp_migrate(NULL, true, caps, true, resume, &err);
> if (hmp_handle_error(mon, err)) {
> return;
> --
> 2.43.7
>
--
-----Open up your eyes, open up your mind, open up your code -------
/ Dr. David Alan Gilbert | Running GNU/Linux | Happy \
\ dave @ treblig.org | | In Hex /
\ _________________________|_____ http://www.treblig.org |_______/
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH 1/1] migration/cpr: Add HMP support for cpr-transfer
2026-06-23 12:24 ` Dr. David Alan Gilbert
@ 2026-06-23 13:03 ` Peter Xu
0 siblings, 0 replies; 4+ messages in thread
From: Peter Xu @ 2026-06-23 13:03 UTC (permalink / raw)
To: Dr. David Alan Gilbert
Cc: Dongli Zhang, qemu-devel, farosas, maciej.szmigiero, mark.kanda,
bchaney
On Tue, Jun 23, 2026 at 12:24:57PM +0000, Dr. David Alan Gilbert wrote:
> * Dongli Zhang (dongli.zhang@oracle.com) wrote:
> > Currently the cpr-transfer source QEMU instance cannot be driven entirely
> > via HMP. The source must use QMP in order to specify both the
> > main migration channel and the CPR channel.
> >
> > Extend the HMP migrate command with an optional CPR channel URI. When the
> > migration mode is cpr-transfer, HMP uses this URI to build a
> > CPR MigrationChannel in addition to the main migration channel. The new
> > argument is rejected unless the migration mode is cpr-transfer, so existing
> > HMP migrate usage is unchanged.
> >
> > For example, source QEMU HMP commands can be something like below. The
> > "unix:/tmp/cpr.sock" is for CPR URI.
> >
> > (qemu) migrate_set_parameter mode cpr-transfer
> > (qemu) migrate tcp:0:50002 unix:/tmp/cpr.sock
> >
> > Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
>
> Yeh this looks OK to me; I don't see a check for if you do:
> (qemu) migrate_set_parameter mode cpr-transfer
> (qemu) migrate tcp:0:50002
>
> Does that get caught by the qmp_migrate or should you add a check here?
>
> I do have a slight preference for using flag optional parameters rather
> than positional, e.g.
>
> migrate -c unix:/tmp/cpr.sock tcp:0:50002
>
> but I wouldn't insist on it.
I'll also vote for that.
Thanks,
--
Peter Xu
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/1] migration/cpr: Add HMP support for cpr-transfer
2026-06-21 7:26 [PATCH 1/1] migration/cpr: Add HMP support for cpr-transfer Dongli Zhang
2026-06-23 12:24 ` Dr. David Alan Gilbert
@ 2026-06-24 15:26 ` Fabiano Rosas
1 sibling, 0 replies; 4+ messages in thread
From: Fabiano Rosas @ 2026-06-24 15:26 UTC (permalink / raw)
To: Dongli Zhang, qemu-devel
Cc: dave, peterx, maciej.szmigiero, mark.kanda, bchaney
Dongli Zhang <dongli.zhang@oracle.com> writes:
> Currently the cpr-transfer source QEMU instance cannot be driven entirely
> via HMP. The source must use QMP in order to specify both the
> main migration channel and the CPR channel.
>
> Extend the HMP migrate command with an optional CPR channel URI. When the
> migration mode is cpr-transfer, HMP uses this URI to build a
> CPR MigrationChannel in addition to the main migration channel. The new
> argument is rejected unless the migration mode is cpr-transfer, so existing
> HMP migrate usage is unchanged.
>
> For example, source QEMU HMP commands can be something like below. The
> "unix:/tmp/cpr.sock" is for CPR URI.
>
> (qemu) migrate_set_parameter mode cpr-transfer
> (qemu) migrate tcp:0:50002 unix:/tmp/cpr.sock
>
> Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
> ---
> hmp-commands.hx | 11 +++++++----
> migration/migration-hmp-cmds.c | 18 ++++++++++++++++++
> 2 files changed, 25 insertions(+), 4 deletions(-)
>
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index 7ae2468a3d..021e51b142 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -928,16 +928,17 @@ ERST
>
> {
> .name = "migrate",
> - .args_type = "detach:-d,resume:-r,uri:s",
> - .params = "[-d] [-r] uri",
> + .args_type = "detach:-d,resume:-r,uri:s,uri-cpr:s?",
> + .params = "[-d] [-r] uri [uri-cpr]",
> .help = "migrate to URI (using -d to not wait for completion)"
> - "\n\t\t\t -r to resume a paused postcopy migration",
> + "\n\t\t\t -r to resume a paused postcopy migration"
> + "\n\t\t\t uri-cpr specifies CPR URI for cpr-transfer mode",
> .cmd = hmp_migrate,
> },
>
>
> SRST
> -``migrate [-d] [-r]`` *uri*
> +``migrate [-d] [-r]`` *uri* [*uri-cpr*]
> Migrate the VM to *uri*.
>
> ``-d``
> @@ -945,6 +946,8 @@ SRST
> query an ongoing migration process, use "info migrate".
> ``-r``
> Resume a paused postcopy migration.
> + ``uri-cpr``
> + Specify CPR URI for cpr-transfer mode. It must be a UNIX domain socket.
> ERST
>
> {
> diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
> index 8b385f560e..42ca652bb3 100644
> --- a/migration/migration-hmp-cmds.c
> +++ b/migration/migration-hmp-cmds.c
> @@ -836,9 +836,11 @@ void hmp_migrate(Monitor *mon, const QDict *qdict)
> bool detach = qdict_get_try_bool(qdict, "detach", false);
> bool resume = qdict_get_try_bool(qdict, "resume", false);
> const char *uri = qdict_get_str(qdict, "uri");
> + const char *uri_cpr = qdict_get_try_str(qdict, "uri-cpr");
> Error *err = NULL;
> g_autoptr(MigrationChannelList) caps = NULL;
> g_autoptr(MigrationChannel) channel = NULL;
> + g_autoptr(MigrationChannel) channel_cpr = NULL;
>
> if (!migrate_uri_parse(uri, &channel, &err)) {
> hmp_handle_error(mon, err);
> @@ -846,6 +848,22 @@ void hmp_migrate(Monitor *mon, const QDict *qdict)
> }
> QAPI_LIST_PREPEND(caps, g_steal_pointer(&channel));
>
> + if (uri_cpr) {
> + if (migrate_mode() != MIG_MODE_CPR_TRANSFER) {
> + error_setg(&err, "uri-cpr requires cpr-transfer mode");
Most users probably won't know what an uri-cpr is. Maybe: "a second uri
can only be used in cpr-transfer mode".
> + hmp_handle_error(mon, err);
> + return;
> + }
> +
> + if (!migrate_uri_parse(uri_cpr, &channel_cpr, &err)) {
> + hmp_handle_error(mon, err);
> + return;
> + }
> +
> + channel_cpr->channel_type = MIGRATION_CHANNEL_TYPE_CPR;
> + QAPI_LIST_PREPEND(caps, g_steal_pointer(&channel_cpr));
> + }
> +
> qmp_migrate(NULL, true, caps, true, resume, &err);
> if (hmp_handle_error(mon, err)) {
> return;
^ permalink raw reply [flat|nested] 4+ messages in thread
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2026-06-21 7:26 [PATCH 1/1] migration/cpr: Add HMP support for cpr-transfer Dongli Zhang
2026-06-23 12:24 ` Dr. David Alan Gilbert
2026-06-23 13:03 ` Peter Xu
2026-06-24 15:26 ` Fabiano Rosas
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