[PATCH 0/8] colo migration cleanups

[PATCH 0/8] colo migration cleanups

[Lukas Straub]

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Hello Everyone,
Here are some cleanups around the colo migration code. Notably, we only
support the same qemu version on both sides for now. Though in this
patchset I still try to be support migration to a newer qemu version.

Lukas Straub (8):
  colo: Only support the same qemu version on source and destination
  colo: Setup ram cache in normal migration path
  colo: Replace migration_incoming_colo_enabled() with migrate_colo()
  colo: Remove ENABLE_COLO loadvm command functions
  colo: Don't send ENABLE_COLO command
  colo: Reject colo with postcopy capability enabled
  colo: Reject colo with block migration capability enabled
  ram: Remove useless colo special-casing

 docs/COLO-FT.txt         |  2 ++
 include/migration/colo.h |  3 --
 migration/colo.c         |  2 +-
 migration/migration.c    | 63 ++++++++++------------------------------
 migration/options.c      | 14 +++++++++
 migration/ram.c          | 14 ++++-----
 migration/savevm.c       | 21 +-------------
 migration/savevm.h       |  1 -
 migration/trace-events   |  1 -
 9 files changed, 41 insertions(+), 80 deletions(-)

-- 
2.39.2

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[PATCH 1/8] colo: Only support the same qemu version on source and destination

[Lukas Straub]

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Signed-off-by: Lukas Straub <lukasstraub2@web.de>
---
 docs/COLO-FT.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/docs/COLO-FT.txt b/docs/COLO-FT.txt
index 2e760a4aee..8e64480dbd 100644
--- a/docs/COLO-FT.txt
+++ b/docs/COLO-FT.txt
@@ -148,6 +148,8 @@ in test procedure.
 Note: Here we are running both instances on the same host for testing,
 change the IP Addresses if you want to run it on two hosts. Initially
 127.0.0.1 is the Primary Host and 127.0.0.2 is the Secondary Host.
+Note: COLO is a experimental feature, so currently is should only be used
+with the same qemu version on sourcee and target.
 
 == Startup qemu ==
 1. Primary:
-- 
2.39.2


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[PATCH 2/8] colo: Setup ram cache in normal migration path

[Lukas Straub]

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Now that x-colo capability needs to be always enabled on the
incoming side we can use that to initialize the ram cache in
the normal migration path.

Signed-off-by: Lukas Straub <lukasstraub2@web.de>
---
 migration/migration.c | 16 ++++++++++++----
 migration/savevm.c    | 10 +---------
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index dc05c6f6ea..050bd8ffc8 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -404,10 +404,6 @@ int migration_incoming_enable_colo(void)
         return -EINVAL;
     }
 
-    if (ram_block_discard_disable(true)) {
-        error_report("COLO: cannot disable RAM discard");
-        return -EBUSY;
-    }
     migration_colo_enabled = true;
     return 0;
 }
@@ -519,6 +515,18 @@ process_incoming_migration_co(void *opaque)
         goto fail;
     }
 
+    if (migrate_colo()) {
+        if (ram_block_discard_disable(true)) {
+            error_report("COLO: cannot disable RAM discard");
+            goto fail;
+        }
+
+        if (colo_init_ram_cache() < 0) {
+            error_report("Init ram cache failed");
+            goto fail;
+        }
+    }
+
     mis->largest_page_size = qemu_ram_pagesize_largest();
     postcopy_state_set(POSTCOPY_INCOMING_NONE);
     migrate_set_state(&mis->state, MIGRATION_STATUS_NONE,
diff --git a/migration/savevm.c b/migration/savevm.c
index bc284087f9..155abb0fda 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -2302,15 +2302,7 @@ static int loadvm_handle_recv_bitmap(MigrationIncomingState *mis,
 
 static int loadvm_process_enable_colo(MigrationIncomingState *mis)
 {
-    int ret = migration_incoming_enable_colo();
-
-    if (!ret) {
-        ret = colo_init_ram_cache();
-        if (ret) {
-            migration_incoming_disable_colo();
-        }
-    }
-    return ret;
+    return migration_incoming_enable_colo();
 }
 
 /*
-- 
2.39.2


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[PATCH 3/8] colo: Replace migration_incoming_colo_enabled() with migrate_colo()

[Lukas Straub]

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Signed-off-by: Lukas Straub <lukasstraub2@web.de>
---
 include/migration/colo.h | 1 -
 migration/colo.c         | 2 +-
 migration/migration.c    | 7 +------
 migration/ram.c          | 2 +-
 4 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/include/migration/colo.h b/include/migration/colo.h
index eaac07f26d..4a1955067b 100644
--- a/include/migration/colo.h
+++ b/include/migration/colo.h
@@ -27,7 +27,6 @@ bool migration_in_colo_state(void);
 /* loadvm */
 int migration_incoming_enable_colo(void);
 void migration_incoming_disable_colo(void);
-bool migration_incoming_colo_enabled(void);
 bool migration_incoming_in_colo_state(void);
 
 COLOMode get_colo_mode(void);
diff --git a/migration/colo.c b/migration/colo.c
index 72f4f7b37e..8b0e7c9af3 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -927,7 +927,7 @@ int coroutine_fn colo_incoming_co(void)
 
     assert(qemu_mutex_iothread_locked());
 
-    if (!migration_incoming_colo_enabled()) {
+    if (!migrate_colo()) {
         return 0;
     }
 
diff --git a/migration/migration.c b/migration/migration.c
index 050bd8ffc8..2506fd63f7 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -379,11 +379,6 @@ int migrate_send_rp_req_pages(MigrationIncomingState *mis,
 }
 
 static bool migration_colo_enabled;
-bool migration_incoming_colo_enabled(void)
-{
-    return migration_colo_enabled;
-}
-
 void migration_incoming_disable_colo(void)
 {
     ram_block_discard_disable(false);
@@ -484,7 +479,7 @@ static void process_incoming_migration_bh(void *opaque)
         } else {
             runstate_set(RUN_STATE_PAUSED);
         }
-    } else if (migration_incoming_colo_enabled()) {
+    } else if (migrate_colo()) {
         migration_incoming_disable_colo();
         vm_start();
     } else {
diff --git a/migration/ram.c b/migration/ram.c
index 5283a75f02..e3eadd08cd 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -3892,7 +3892,7 @@ static int ram_load_precopy(QEMUFile *f)
              * speed of the migration, but it obviously reduce the downtime of
              * back-up all SVM'S memory in COLO preparing stage.
              */
-            if (migration_incoming_colo_enabled()) {
+            if (migrate_colo()) {
                 if (migration_incoming_in_colo_state()) {
                     /* In COLO stage, put all pages into cache temporarily */
                     host = colo_cache_from_block_offset(block, addr, true);
-- 
2.39.2


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[PATCH 4/8] colo: Remove ENABLE_COLO loadvm command functions

[Lukas Straub]

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No need for it anymore now that x-colo capability is required
on incoming side. Still accept the command as noop, for
compatibility with older qemu.

Signed-off-by: Lukas Straub <lukasstraub2@web.de>
---
 include/migration/colo.h |  2 --
 migration/migration.c    | 26 --------------------------
 migration/savevm.c       |  7 +------
 3 files changed, 1 insertion(+), 34 deletions(-)

diff --git a/include/migration/colo.h b/include/migration/colo.h
index 4a1955067b..addbc24fcf 100644
--- a/include/migration/colo.h
+++ b/include/migration/colo.h
@@ -25,8 +25,6 @@ void migrate_start_colo_process(MigrationState *s);
 bool migration_in_colo_state(void);
 
 /* loadvm */
-int migration_incoming_enable_colo(void);
-void migration_incoming_disable_colo(void);
 bool migration_incoming_in_colo_state(void);
 
 COLOMode get_colo_mode(void);
diff --git a/migration/migration.c b/migration/migration.c
index 2506fd63f7..1d347533f9 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -378,31 +378,6 @@ int migrate_send_rp_req_pages(MigrationIncomingState *mis,
     return migrate_send_rp_message_req_pages(mis, rb, start);
 }
 
-static bool migration_colo_enabled;
-void migration_incoming_disable_colo(void)
-{
-    ram_block_discard_disable(false);
-    migration_colo_enabled = false;
-}
-
-int migration_incoming_enable_colo(void)
-{
-#ifndef CONFIG_REPLICATION
-    error_report("ENABLE_COLO command come in migration stream, but COLO "
-                 "module is not built in");
-    return -ENOTSUP;
-#endif
-
-    if (!migrate_colo()) {
-        error_report("ENABLE_COLO command come in migration stream, but c-colo "
-                     "capability is not set");
-        return -EINVAL;
-    }
-
-    migration_colo_enabled = true;
-    return 0;
-}
-
 void migrate_add_address(SocketAddress *address)
 {
     MigrationIncomingState *mis = migration_incoming_get_current();
@@ -480,7 +455,6 @@ static void process_incoming_migration_bh(void *opaque)
             runstate_set(RUN_STATE_PAUSED);
         }
     } else if (migrate_colo()) {
-        migration_incoming_disable_colo();
         vm_start();
     } else {
         runstate_set(global_state_get_runstate());
diff --git a/migration/savevm.c b/migration/savevm.c
index 155abb0fda..3a1de15bd0 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -2300,11 +2300,6 @@ static int loadvm_handle_recv_bitmap(MigrationIncomingState *mis,
     return 0;
 }
 
-static int loadvm_process_enable_colo(MigrationIncomingState *mis)
-{
-    return migration_incoming_enable_colo();
-}
-
 /*
  * Process an incoming 'QEMU_VM_COMMAND'
  * 0           just a normal return
@@ -2387,7 +2382,7 @@ static int loadvm_process_command(QEMUFile *f)
         return loadvm_handle_recv_bitmap(mis, len);
 
     case MIG_CMD_ENABLE_COLO:
-        return loadvm_process_enable_colo(mis);
+        return 0;
     }
 
     return 0;
-- 
2.39.2


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[PATCH 5/8] colo: Don't send ENABLE_COLO command

[Lukas Straub]

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We should only migrate to qemu with newer version, and there it's
not needed anymore.

Signed-off-by: Lukas Straub <lukasstraub2@web.de>
---
 migration/migration.c  | 5 -----
 migration/savevm.c     | 6 ------
 migration/savevm.h     | 1 -
 migration/trace-events | 1 -
 4 files changed, 13 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 1d347533f9..a954ff4f7d 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2929,11 +2929,6 @@ static void *migration_thread(void *opaque)
         qemu_savevm_send_postcopy_advise(s->to_dst_file);
     }
 
-    if (migrate_colo()) {
-        /* Notify migration destination that we enable COLO */
-        qemu_savevm_send_colo_enable(s->to_dst_file);
-    }
-
     qemu_savevm_state_setup(s->to_dst_file);
 
     qemu_savevm_wait_unplug(s, MIGRATION_STATUS_SETUP,
diff --git a/migration/savevm.c b/migration/savevm.c
index 3a1de15bd0..5986f852b2 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1035,12 +1035,6 @@ static void qemu_savevm_command_send(QEMUFile *f,
     qemu_fflush(f);
 }
 
-void qemu_savevm_send_colo_enable(QEMUFile *f)
-{
-    trace_savevm_send_colo_enable();
-    qemu_savevm_command_send(f, MIG_CMD_ENABLE_COLO, 0, NULL);
-}
-
 void qemu_savevm_send_ping(QEMUFile *f, uint32_t value)
 {
     uint32_t buf;
diff --git a/migration/savevm.h b/migration/savevm.h
index fb636735f0..cb3318e9e2 100644
--- a/migration/savevm.h
+++ b/migration/savevm.h
@@ -57,7 +57,6 @@ void qemu_savevm_send_postcopy_ram_discard(QEMUFile *f, const char *name,
                                            uint16_t len,
                                            uint64_t *start_list,
                                            uint64_t *length_list);
-void qemu_savevm_send_colo_enable(QEMUFile *f);
 void qemu_savevm_live_state(QEMUFile *f);
 int qemu_save_device_state(QEMUFile *f);
 
diff --git a/migration/trace-events b/migration/trace-events
index cdaef7a1ea..bd3ec40e31 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -36,7 +36,6 @@ savevm_send_ping(uint32_t val) "0x%x"
 savevm_send_postcopy_listen(void) ""
 savevm_send_postcopy_run(void) ""
 savevm_send_postcopy_resume(void) ""
-savevm_send_colo_enable(void) ""
 savevm_send_recv_bitmap(char *name) "%s"
 savevm_state_setup(void) ""
 savevm_state_resume_prepare(void) ""
-- 
2.39.2


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[PATCH 6/8] colo: Reject colo with postcopy capability enabled

[Lukas Straub]

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Signed-off-by: Lukas Straub <lukasstraub2@web.de>
---
 migration/migration.c | 5 +++--
 migration/options.c   | 9 +++++++++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index a954ff4f7d..9860f960f2 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2333,9 +2333,10 @@ static void migration_completion(MigrationState *s)
         goto fail;
     }
 
-    if (migrate_colo() && s->state == MIGRATION_STATUS_ACTIVE) {
+    if (migrate_colo()) {
         /* COLO does not support postcopy */
-        migrate_set_state(&s->state, MIGRATION_STATUS_ACTIVE,
+        assert(s->state != MIGRATION_STATUS_POSTCOPY_ACTIVE);
+        migrate_set_state(&s->state, current_active_state,
                           MIGRATION_STATUS_COLO);
     } else {
         migrate_set_state(&s->state, current_active_state,
diff --git a/migration/options.c b/migration/options.c
index b62ab30cd5..d3d4525d40 100644
--- a/migration/options.c
+++ b/migration/options.c
@@ -445,8 +445,17 @@ bool migrate_caps_check(bool *old_caps, bool *new_caps, Error **errp)
         error_append_hint(errp, "Please enable replication before COLO.\n");
         return false;
     }
+#else
+    if (new_caps[MIGRATION_CAPABILITY_X_COLO]) {
+        if (new_caps[MIGRATION_CAPABILITY_POSTCOPY_RAM]) {
+            error_setg(errp, "COLO is not compatible with postcopy");
+            return false;
+        }
+    }
 #endif
 
+
+
     if (new_caps[MIGRATION_CAPABILITY_POSTCOPY_RAM]) {
         /* This check is reasonably expensive, so only when it's being
          * set the first time, also it's only the destination that needs
-- 
2.39.2


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[PATCH 7/8] colo: Reject colo with block migration capability enabled

[Lukas Straub]

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Signed-off-by: Lukas Straub <lukasstraub2@web.de>
---
 migration/migration.c | 4 ----
 migration/options.c   | 5 +++++
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 9860f960f2..270130579f 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1571,10 +1571,6 @@ static bool migrate_prepare(MigrationState *s, bool blk, bool blk_inc,
     }
 
     if (blk || blk_inc) {
-        if (migrate_colo()) {
-            error_setg(errp, "No disk migration is required in COLO mode");
-            return false;
-        }
         if (migrate_block() || migrate_block_incremental()) {
             error_setg(errp, "Command options are incompatible with "
                        "current migration capabilities");
diff --git a/migration/options.c b/migration/options.c
index d3d4525d40..1e9659fcb3 100644
--- a/migration/options.c
+++ b/migration/options.c
@@ -451,6 +451,11 @@ bool migrate_caps_check(bool *old_caps, bool *new_caps, Error **errp)
             error_setg(errp, "COLO is not compatible with postcopy");
             return false;
         }
+
+        if (new_caps[MIGRATION_CAPABILITY_BLOCK]) {
+            error_setg(errp, "COLO is not compatible with block migration");
+            return false;
+        }
     }
 #endif
 
-- 
2.39.2


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[PATCH 8/8] ram: Remove useless colo special-casing

[Lukas Straub]

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This is not needed, as colo primary side everything is more or less
a new migration for every checkpoint.

Also, we only enter colo mode after the precopy migration is finished
so this if is always taken. Still add an assert just in case.

Signed-off-by: Lukas Straub <lukasstraub2@web.de>
---
 migration/ram.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index e3eadd08cd..e5c1146360 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -2994,17 +2994,17 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
     RAMBlock *block;
     int ret;
 
+    assert(!migration_in_colo_state());
+
     if (compress_threads_save_setup()) {
         return -1;
     }
 
-    /* migration has already setup the bitmap, reuse it. */
-    if (!migration_in_colo_state()) {
-        if (ram_init_all(rsp) != 0) {
-            compress_threads_save_cleanup();
-            return -1;
-        }
+    if (ram_init_all(rsp) != 0) {
+        compress_threads_save_cleanup();
+        return -1;
     }
+
     (*rsp)->pss[RAM_CHANNEL_PRECOPY].pss_channel = f;
 
     WITH_RCU_READ_LOCK_GUARD() {
-- 
2.39.2

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RE: [PATCH 1/8] colo: Only support the same qemu version on source and destination

[Dong, Eddie]

> -----Original Message-----
> From: qemu-devel-bounces+eddie.dong=intel.com@nongnu.org <qemu-
> devel-bounces+eddie.dong=intel.com@nongnu.org> On Behalf Of Lukas
> Straub
> Sent: Thursday, June 22, 2023 5:15 AM
> To: qemu-devel <qemu-devel@nongnu.org>
> Cc: Zhang, Hailiang <zhanghailiang@xfusion.com>; Juan Quintela
> <quintela@redhat.com>; Peter Xu <peterx@redhat.com>; Leonardo Bras
> <leobras@redhat.com>; Zhang, Chen <chen.zhang@intel.com>
> Subject: [PATCH 1/8] colo: Only support the same qemu version on source
> and destination
> 
> Signed-off-by: Lukas Straub <lukasstraub2@web.de>
> ---
>  docs/COLO-FT.txt | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/docs/COLO-FT.txt b/docs/COLO-FT.txt index
> 2e760a4aee..8e64480dbd 100644
> --- a/docs/COLO-FT.txt
> +++ b/docs/COLO-FT.txt
> @@ -148,6 +148,8 @@ in test procedure.
>  Note: Here we are running both instances on the same host for testing,
> change the IP Addresses if you want to run it on two hosts. Initially
>  127.0.0.1 is the Primary Host and 127.0.0.2 is the Secondary Host.
> +Note: COLO is a experimental feature, 
an experimental feature

>so currently is should only be
it should ...

> +used with the same qemu version on sourcee and target.
> 
>  == Startup qemu ==
>  1. Primary:
> --
> 2.39.2

RE: [PATCH 1/8] colo: Only support the same qemu version on source and destination

[Zhang, Chen]

> -----Original Message-----
> From: Dong, Eddie <eddie.dong@intel.com>
> Sent: Friday, June 23, 2023 1:17 AM
> To: Lukas Straub <lukasstraub2@web.de>; qemu-devel <qemu-
> devel@nongnu.org>
> Cc: Zhang, Hailiang <zhanghailiang@xfusion.com>; Juan Quintela
> <quintela@redhat.com>; Peter Xu <peterx@redhat.com>; Leonardo Bras
> <leobras@redhat.com>; Zhang, Chen <chen.zhang@intel.com>
> Subject: RE: [PATCH 1/8] colo: Only support the same qemu version on
> source and destination
> 
> 
> 
> > -----Original Message-----
> > From: qemu-devel-bounces+eddie.dong=intel.com@nongnu.org <qemu-
> > devel-bounces+eddie.dong=intel.com@nongnu.org> On Behalf Of Lukas
> > Straub
> > Sent: Thursday, June 22, 2023 5:15 AM
> > To: qemu-devel <qemu-devel@nongnu.org>
> > Cc: Zhang, Hailiang <zhanghailiang@xfusion.com>; Juan Quintela
> > <quintela@redhat.com>; Peter Xu <peterx@redhat.com>; Leonardo Bras
> > <leobras@redhat.com>; Zhang, Chen <chen.zhang@intel.com>
> > Subject: [PATCH 1/8] colo: Only support the same qemu version on
> > source and destination
> >
> > Signed-off-by: Lukas Straub <lukasstraub2@web.de>
> > ---
> >  docs/COLO-FT.txt | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/docs/COLO-FT.txt b/docs/COLO-FT.txt index
> > 2e760a4aee..8e64480dbd 100644
> > --- a/docs/COLO-FT.txt
> > +++ b/docs/COLO-FT.txt
> > @@ -148,6 +148,8 @@ in test procedure.
> >  Note: Here we are running both instances on the same host for
> > testing, change the IP Addresses if you want to run it on two hosts.
> > Initially
> >  127.0.0.1 is the Primary Host and 127.0.0.2 is the Secondary Host.
> > +Note: COLO is a experimental feature,
> an experimental feature
> 
> >so currently is should only be
> it should ...
> 
> > +used with the same qemu version on sourcee and target.

S/sourcee/source

Thanks
Chen

> >
> >  == Startup qemu ==
> >  1. Primary:
> > --
> > 2.39.2

RE: [PATCH 2/8] colo: Setup ram cache in normal migration path

[Zhang, Chen]

> -----Original Message-----
> From: Lukas Straub <lukasstraub2@web.de>
> Sent: Thursday, June 22, 2023 8:15 PM
> To: qemu-devel <qemu-devel@nongnu.org>
> Cc: Zhang, Hailiang <zhanghailiang@xfusion.com>; Juan Quintela
> <quintela@redhat.com>; Peter Xu <peterx@redhat.com>; Leonardo Bras
> <leobras@redhat.com>; Zhang, Chen <chen.zhang@intel.com>
> Subject: [PATCH 2/8] colo: Setup ram cache in normal migration path
> 
> Now that x-colo capability needs to be always enabled on the incoming side
> we can use that to initialize the ram cache in the normal migration path.
> 
> Signed-off-by: Lukas Straub <lukasstraub2@web.de>
> ---
>  migration/migration.c | 16 ++++++++++++----
>  migration/savevm.c    | 10 +---------
>  2 files changed, 13 insertions(+), 13 deletions(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c index
> dc05c6f6ea..050bd8ffc8 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -404,10 +404,6 @@ int migration_incoming_enable_colo(void)
>          return -EINVAL;
>      }
> 
> -    if (ram_block_discard_disable(true)) {
> -        error_report("COLO: cannot disable RAM discard");
> -        return -EBUSY;
> -    }

COLO may call here when occur each checkpoint to pin the guest memory, in the Colo_incoming_process_checkpoint().
Is it still working after move to the "process_incoming_migration_co()" ?


>      migration_colo_enabled = true;
>      return 0;
>  }
> @@ -519,6 +515,18 @@ process_incoming_migration_co(void *opaque)
>          goto fail;
>      }
> 
> +    if (migrate_colo()) {
> +        if (ram_block_discard_disable(true)) {
> +            error_report("COLO: cannot disable RAM discard");
> +            goto fail;
> +        }
> +
> +        if (colo_init_ram_cache() < 0) {
> +            error_report("Init ram cache failed");

Change the code path to here need to add COLO tag to the error:
error_report("Init COLO ram cache failed");

It looks here removed the original  migration_incoming_disable_colo(),
But maybe it's OK for goto fail directly.

Thanks
Chen

> +            goto fail;
> +        }
> +    }
> +
>      mis->largest_page_size = qemu_ram_pagesize_largest();
>      postcopy_state_set(POSTCOPY_INCOMING_NONE);
>      migrate_set_state(&mis->state, MIGRATION_STATUS_NONE, diff --git
> a/migration/savevm.c b/migration/savevm.c index bc284087f9..155abb0fda
> 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -2302,15 +2302,7 @@ static int
> loadvm_handle_recv_bitmap(MigrationIncomingState *mis,
> 
>  static int loadvm_process_enable_colo(MigrationIncomingState *mis)  {
> -    int ret = migration_incoming_enable_colo();
> -
> -    if (!ret) {
> -        ret = colo_init_ram_cache();
> -        if (ret) {
> -            migration_incoming_disable_colo();
> -        }
> -    }
> -    return ret;
> +    return migration_incoming_enable_colo();
>  }
> 
>  /*
> --
> 2.39.2