From 7cbfdb081de6e4eb684447ba48869082df798419 Mon Sep 17 00:00:00 2001
Message-Id: <7cbfdb081de6e4eb684447ba48869082df798419@dist-git>
From: Jiri Denemark <jdenemar@redhat.com>
Date: Wed, 22 Jun 2022 16:12:02 +0200
Subject: [PATCH] qemu_migration: Restore original memory locking limit
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

For RDMA migration we update memory locking limit, but never set it back
once migration finishes (on the destination host) or aborts (on the
source host).

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
(cherry picked from commit d4d3bb813031275c2c7cf72724b83c97ce82ab7a)

https://bugzilla.redhat.com/show_bug.cgi?id=2117272

Conflicts:
	src/qemu/qemu_migration.c
            - post-copy resovery not backported

The original 8.7.0 backport contained a bug which was later fixed by
"qemu_migration: Fix restoring memlock limit on destination". This
backport includes the follow up fix squashed in.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 src/qemu/qemu_domain.c    | 12 ++++++++++++
 src/qemu/qemu_domain.h    |  3 +++
 src/qemu/qemu_migration.c | 11 +++++++++--
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index a81789f194..c24d1e4d53 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -2389,6 +2389,11 @@ qemuDomainObjPrivateXMLFormat(virBuffer *buf,
                           priv->originalMemlock);
     }
 
+    if (priv->preMigrationMemlock > 0) {
+        virBufferAsprintf(buf, "<preMigrationMemlock>%llu</preMigrationMemlock>\n",
+                          priv->preMigrationMemlock);
+    }
+
     return 0;
 }
 
@@ -3117,6 +3122,13 @@ qemuDomainObjPrivateXMLParse(xmlXPathContextPtr ctxt,
         goto error;
     }
 
+    if (virXPathULongLong("string(./preMigrationMemlock)", ctxt,
+                          &priv->preMigrationMemlock) == -2) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("failed to parse pre-migration memlock limit"));
+        return -1;
+    }
+
     return 0;
 
  error:
diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index 6d1d23439a..d6e8a7a0fb 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -146,6 +146,9 @@ struct _qemuDomainObjPrivate {
     int nbdPort; /* Port used for migration with NBD */
     unsigned short migrationPort;
     int preMigrationState;
+    unsigned long long preMigrationMemlock; /* Original RLIMIT_MEMLOCK in case
+                                               it was changed for the current
+                                               migration job. */
 
     virChrdevs *devs;
 
diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 10338f8e87..01102c4300 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -2974,7 +2974,8 @@ qemuMigrationDstPrepareAny(virQEMUDriver *driver,
 
     if (STREQ_NULLABLE(protocol, "rdma") &&
         vm->def->mem.hard_limit > 0 &&
-        qemuDomainSetMaxMemLock(vm, vm->def->mem.hard_limit << 10, NULL) < 0) {
+        qemuDomainSetMaxMemLock(vm, vm->def->mem.hard_limit << 10,
+                                &priv->preMigrationMemlock) < 0) {
         goto stopjob;
     }
 
@@ -3451,6 +3452,7 @@ qemuMigrationSrcConfirmPhase(virQEMUDriver *driver,
                                          VIR_DOMAIN_EVENT_STOPPED_MIGRATED);
         virObjectEventStateQueue(driver->domainEventState, event);
         qemuDomainEventEmitJobCompleted(driver, vm);
+        priv->preMigrationMemlock = 0;
     } else {
         virErrorPtr orig_err;
         int reason;
@@ -3471,6 +3473,7 @@ qemuMigrationSrcConfirmPhase(virQEMUDriver *driver,
 
         qemuMigrationParamsReset(driver, vm, QEMU_ASYNC_JOB_MIGRATION_OUT,
                                  jobPriv->migParams, priv->job.apiFlags);
+        qemuDomainSetMaxMemLock(vm, 0, &priv->preMigrationMemlock);
 
         qemuDomainSaveStatus(vm);
     }
@@ -4224,7 +4227,8 @@ qemuMigrationSrcRun(virQEMUDriver *driver,
     case MIGRATION_DEST_HOST:
         if (STREQ(spec->dest.host.protocol, "rdma") &&
             vm->def->mem.hard_limit > 0 &&
-            qemuDomainSetMaxMemLock(vm, vm->def->mem.hard_limit << 10, NULL) < 0) {
+            qemuDomainSetMaxMemLock(vm, vm->def->mem.hard_limit << 10,
+                                    &priv->preMigrationMemlock) < 0) {
             goto exit_monitor;
         }
         rc = qemuMonitorMigrateToHost(priv->mon, migrate_flags,
@@ -5408,6 +5412,7 @@ qemuMigrationSrcPerformPhase(virQEMUDriver *driver,
     if (ret < 0) {
         qemuMigrationParamsReset(driver, vm, QEMU_ASYNC_JOB_MIGRATION_OUT,
                                  jobPriv->migParams, priv->job.apiFlags);
+        qemuDomainSetMaxMemLock(vm, 0, &priv->preMigrationMemlock);
         qemuMigrationJobFinish(driver, vm);
     } else {
         qemuMigrationJobContinue(vm);
@@ -5869,6 +5874,8 @@ qemuMigrationDstFinish(virQEMUDriver *driver,
          */
         if (inPostCopy)
             g_clear_pointer(&priv->job.completed, qemuDomainJobInfoFree);
+
+        qemuDomainSetMaxMemLock(vm, 0, &priv->preMigrationMemlock);
     }
 
     qemuMigrationParamsReset(driver, vm, QEMU_ASYNC_JOB_MIGRATION_IN,
-- 
2.35.1