[libvirt] [PATCH] qemu: Reject migration with memory-hotplug if destination doesn't support it

Peter Krempa pkrempa at redhat.com
Thu Jul 30 14:47:02 UTC 2015


If destination libvirt doesn't support memory hotplug since all the
support was introduced by adding new elements the destination would
attempt to start qemu with an invalid configuration. The worse part is
that qemu might hang in such situation.

Fix this by sending a required migration feature called 'memory-hotplug'
to the destination. If the destination doesn't recognize it it will fail
the migration.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1248350
---
 src/qemu/qemu_migration.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index f5866c4..824126f 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -86,6 +86,7 @@ enum qemuMigrationCookieFlags {
     QEMU_MIGRATION_COOKIE_FLAG_NETWORK,
     QEMU_MIGRATION_COOKIE_FLAG_NBD,
     QEMU_MIGRATION_COOKIE_FLAG_STATS,
+    QEMU_MIGRATION_COOKIE_FLAG_MEMORY_HOTPLUG,

     QEMU_MIGRATION_COOKIE_FLAG_LAST
 };
@@ -98,7 +99,8 @@ VIR_ENUM_IMPL(qemuMigrationCookieFlag,
               "persistent",
               "network",
               "nbd",
-              "statistics");
+              "statistics",
+              "memory-hotplug");

 enum qemuMigrationCookieFeatures {
     QEMU_MIGRATION_COOKIE_GRAPHICS  = (1 << QEMU_MIGRATION_COOKIE_FLAG_GRAPHICS),
@@ -107,6 +109,7 @@ enum qemuMigrationCookieFeatures {
     QEMU_MIGRATION_COOKIE_NETWORK = (1 << QEMU_MIGRATION_COOKIE_FLAG_NETWORK),
     QEMU_MIGRATION_COOKIE_NBD = (1 << QEMU_MIGRATION_COOKIE_FLAG_NBD),
     QEMU_MIGRATION_COOKIE_STATS = (1 << QEMU_MIGRATION_COOKIE_FLAG_STATS),
+    QEMU_MIGRATION_COOKIE_MEMORY_HOTPLUG = (1 << QEMU_MIGRATION_COOKIE_FLAG_MEMORY_HOTPLUG),
 };

 typedef struct _qemuMigrationCookieGraphics qemuMigrationCookieGraphics;
@@ -1352,6 +1355,9 @@ qemuMigrationBakeCookie(qemuMigrationCookiePtr mig,
         qemuMigrationCookieAddStatistics(mig, dom) < 0)
         return -1;

+    if (flags & QEMU_MIGRATION_COOKIE_MEMORY_HOTPLUG)
+        mig->flagsMandatory |= QEMU_MIGRATION_COOKIE_MEMORY_HOTPLUG;
+
     if (!(*cookieout = qemuMigrationCookieXMLFormatStr(driver, mig)))
         return -1;

@@ -2974,6 +2980,11 @@ qemuMigrationBeginPhase(virQEMUDriverPtr driver,
         }
     }

+    if (vm->def->mem.max_memory ||
+        (vm->newDef &&
+         vm->newDef->mem.max_memory))
+        cookieFlags |= QEMU_MIGRATION_COOKIE_MEMORY_HOTPLUG;
+
     if (!(mig = qemuMigrationEatCookie(driver, vm, NULL, 0, 0)))
         goto cleanup;

-- 
2.4.5




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