From b8c791a3fc2767e6d899e3e0c590a93cb0ee7e03 Mon Sep 17 00:00:00 2001

Message-Id: <b8c791a3fc2767e6d899e3e0c590a93cb0ee7e03@dist-git>

From: Jiri Denemark <jdenemar@redhat.com>

Date: Thu, 30 Jun 2022 12:52:38 +0200

Subject: [PATCH] qemu_migration: Apply max-postcopy-bandwidth on post-copy

 resume

When resuming post-copy migration users may want to limit the bandwidth

used by the migration and use a value that is different from the one

specified when the migration was originally started.

Resolves: https://gitlab.com/libvirt/libvirt/-/issues/333

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

(cherry picked from commit 766abdc291ba606379a7d197bff477fef25fb508)

https://bugzilla.redhat.com/show_bug.cgi?id=2111070

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

---

 src/qemu/qemu_migration.c            | 12 ++++++--

 src/qemu/qemu_migration_params.c     | 45 ++++++++++++++++++----------

 src/qemu/qemu_migration_paramspriv.h |  3 +-

 tests/qemumigparamstest.c            |  2 +-

 tests/qemumigrationcookiexmltest.c   |  2 +-

 5 files changed, 42 insertions(+), 22 deletions(-)

diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c

index 285a49c5ff..8a2f5b09a1 100644

--- a/src/qemu/qemu_migration.c

+++ b/src/qemu/qemu_migration.c

@@ -5097,12 +5097,13 @@ qemuMigrationSrcRun(virQEMUDriver *driver,

 static int

 qemuMigrationSrcResume(virDomainObj *vm,

-                       qemuMigrationParams *migParams G_GNUC_UNUSED,

+                       qemuMigrationParams *migParams,

                        const char *cookiein,

                        int cookieinlen,

                        char **cookieout,

                        int *cookieoutlen,

-                       qemuMigrationSpec *spec)

+                       qemuMigrationSpec *spec,

+                       unsigned long flags)

 {

     qemuDomainObjPrivate *priv = vm->privateData;

     virQEMUDriver *driver = priv->driver;

@@ -5119,6 +5120,10 @@ qemuMigrationSrcResume(virDomainObj *vm,

     if (!mig)

         return -1;

+    if (qemuMigrationParamsApply(driver, vm, VIR_ASYNC_JOB_MIGRATION_OUT,

+                                 migParams, flags) < 0)

+        return -1;

+

     if (qemuDomainObjEnterMonitorAsync(driver, vm,

                                        VIR_ASYNC_JOB_MIGRATION_OUT) < 0)

         return -1;

@@ -5200,6 +5205,7 @@ qemuMigrationSrcPerformNative(virQEMUDriver *driver,

     if (STREQ(uribits->scheme, "unix")) {

         if ((flags & VIR_MIGRATE_TLS) &&

+            !(flags & VIR_MIGRATE_POSTCOPY_RESUME) &&

             !qemuMigrationParamsTLSHostnameIsSet(migParams)) {

             virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",

                            _("Explicit destination hostname is required "

@@ -5231,7 +5237,7 @@ qemuMigrationSrcPerformNative(virQEMUDriver *driver,

     if (flags & VIR_MIGRATE_POSTCOPY_RESUME) {

         ret = qemuMigrationSrcResume(vm, migParams, cookiein, cookieinlen,

-                                     cookieout, cookieoutlen, &spec);

+                                     cookieout, cookieoutlen, &spec, flags);

     } else {

         ret = qemuMigrationSrcRun(driver, vm, persist_xml, cookiein, cookieinlen,

                                   cookieout, cookieoutlen, flags, resource,

diff --git a/src/qemu/qemu_migration_params.c b/src/qemu/qemu_migration_params.c

index a68aed9aa4..6ea0bde13a 100644

--- a/src/qemu/qemu_migration_params.c

+++ b/src/qemu/qemu_migration_params.c

@@ -141,6 +141,7 @@ struct _qemuMigrationParamsTPMapItem {

 typedef struct _qemuMigrationParamInfoItem qemuMigrationParamInfoItem;

 struct _qemuMigrationParamInfoItem {

     qemuMigrationParamType type;

+    bool applyOnPostcopyResume;

 };

 /* Migration capabilities which should always be enabled as long as they

@@ -265,6 +266,7 @@ static const qemuMigrationParamInfoItem qemuMigrationParamInfo[] = {

     },

     [QEMU_MIGRATION_PARAM_MAX_POSTCOPY_BANDWIDTH] = {

         .type = QEMU_MIGRATION_PARAM_TYPE_ULL,

+        .applyOnPostcopyResume = true,

     },

     [QEMU_MIGRATION_PARAM_MULTIFD_CHANNELS] = {

         .type = QEMU_MIGRATION_PARAM_TYPE_INT,

@@ -782,7 +784,8 @@ qemuMigrationParamsFromJSON(virJSONValue *params)

 virJSONValue *

-qemuMigrationParamsToJSON(qemuMigrationParams *migParams)

+qemuMigrationParamsToJSON(qemuMigrationParams *migParams,

+                          bool postcopyResume)

 {

     g_autoptr(virJSONValue) params = virJSONValueNewObject();

     size_t i;

@@ -795,6 +798,9 @@ qemuMigrationParamsToJSON(qemuMigrationParams *migParams)

         if (!pv->set)

             continue;

+        if (postcopyResume && !qemuMigrationParamInfo[i].applyOnPostcopyResume)

+            continue;

+

         switch (qemuMigrationParamInfo[i].type) {

         case QEMU_MIGRATION_PARAM_TYPE_INT:

             rc = virJSONValueObjectAppendNumberInt(params, name, pv->value.i);

@@ -868,6 +874,7 @@ qemuMigrationCapsToJSON(virBitmap *caps,

  *

  * Send parameters stored in @migParams to QEMU. If @apiFlags is non-zero, some

  * parameters that do not make sense for the enabled flags will be ignored.

+ * VIR_MIGRATE_POSTCOPY_RESUME is the only flag checked currently.

  *

  * Returns 0 on success, -1 on failure.

  */

@@ -876,32 +883,38 @@ qemuMigrationParamsApply(virQEMUDriver *driver,

                          virDomainObj *vm,

                          int asyncJob,

                          qemuMigrationParams *migParams,

-                         unsigned long apiFlags G_GNUC_UNUSED)

+                         unsigned long apiFlags)

 {

     qemuDomainObjPrivate *priv = vm->privateData;

     bool xbzrleCacheSize_old = false;

     g_autoptr(virJSONValue) params = NULL;

     g_autoptr(virJSONValue) caps = NULL;

     qemuMigrationParam xbzrle = QEMU_MIGRATION_PARAM_XBZRLE_CACHE_SIZE;

+    bool postcopyResume = !!(apiFlags & VIR_MIGRATE_POSTCOPY_RESUME);

     int ret = -1;

     if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)

         return -1;

-    if (asyncJob == VIR_ASYNC_JOB_NONE) {

-        if (!virBitmapIsAllClear(migParams->caps)) {

-            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",

-                           _("Migration capabilities can only be set by "

-                             "a migration job"));

-            goto cleanup;

-        }

-    } else {

-        if (!(caps = qemuMigrationCapsToJSON(priv->migrationCaps, migParams->caps)))

-            goto cleanup;

+    /* Changing capabilities is only allowed before migration starts, we need

+     * to skip them when resuming post-copy migration.

+     */

+    if (!postcopyResume) {

+        if (asyncJob == VIR_ASYNC_JOB_NONE) {

+            if (!virBitmapIsAllClear(migParams->caps)) {

+                virReportError(VIR_ERR_INTERNAL_ERROR, "%s",

+                               _("Migration capabilities can only be set by "

+                                 "a migration job"));

+                goto cleanup;

+            }

+        } else {

+            if (!(caps = qemuMigrationCapsToJSON(priv->migrationCaps, migParams->caps)))

+                goto cleanup;

-        if (virJSONValueArraySize(caps) > 0 &&

-            qemuMonitorSetMigrationCapabilities(priv->mon, &caps) < 0)

-            goto cleanup;

+            if (virJSONValueArraySize(caps) > 0 &&

+                qemuMonitorSetMigrationCapabilities(priv->mon, &caps) < 0)

+                goto cleanup;

+        }

     }

     /* If QEMU is too old to support xbzrle-cache-size migration parameter,

@@ -917,7 +930,7 @@ qemuMigrationParamsApply(virQEMUDriver *driver,

         migParams->params[xbzrle].set = false;

     }

-    if (!(params = qemuMigrationParamsToJSON(migParams)))

+    if (!(params = qemuMigrationParamsToJSON(migParams, postcopyResume)))

         goto cleanup;

     if (virJSONValueObjectKeysNumber(params) > 0 &&

diff --git a/src/qemu/qemu_migration_paramspriv.h b/src/qemu/qemu_migration_paramspriv.h

index f7e0f51fbd..34d51231ff 100644

--- a/src/qemu/qemu_migration_paramspriv.h

+++ b/src/qemu/qemu_migration_paramspriv.h

@@ -26,7 +26,8 @@

 #pragma once

 virJSONValue *

-qemuMigrationParamsToJSON(qemuMigrationParams *migParams);

+qemuMigrationParamsToJSON(qemuMigrationParams *migParams,

+                          bool postcopyResume);

 qemuMigrationParams *

 qemuMigrationParamsFromJSON(virJSONValue *params);

diff --git a/tests/qemumigparamstest.c b/tests/qemumigparamstest.c

index bcdee5f32b..5d45a9dd58 100644

--- a/tests/qemumigparamstest.c

+++ b/tests/qemumigparamstest.c

@@ -155,7 +155,7 @@ qemuMigParamsTestJSON(const void *opaque)

     if (!(migParams = qemuMigrationParamsFromJSON(paramsIn)))

         return -1;

-    if (!(paramsOut = qemuMigrationParamsToJSON(migParams)) ||

+    if (!(paramsOut = qemuMigrationParamsToJSON(migParams, false)) ||

         !(actualJSON = virJSONValueToString(paramsOut, true)))

         return -1;

diff --git a/tests/qemumigrationcookiexmltest.c b/tests/qemumigrationcookiexmltest.c

index 316bfedd15..9731348b53 100644

--- a/tests/qemumigrationcookiexmltest.c

+++ b/tests/qemumigrationcookiexmltest.c

@@ -333,7 +333,7 @@ testQemuMigrationCookieBlockDirtyBitmaps(const void *opaque)

     qemuMigrationParamsSetBlockDirtyBitmapMapping(migParams, &migParamsBitmaps);

-    if (!(paramsOut = qemuMigrationParamsToJSON(migParams)) ||

+    if (!(paramsOut = qemuMigrationParamsToJSON(migParams, false)) ||

         !(actualJSON = virJSONValueToString(paramsOut, true)))

         return -1;

-- 

2.35.1