From 5f602085f03840e9cef0b53d01ab6e9eaf126382 Mon Sep 17 00:00:00 2001
Message-Id: <5f602085f03840e9cef0b53d01ab6e9eaf126382@dist-git>
From: Peter Krempa <pkrempa@redhat.com>
Date: Fri, 31 Jul 2015 15:19:26 +0200
Subject: [PATCH] qemu: Reject migration with memory-hotplug if destination
 doesn't support it

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
(cherry picked from commit 136f3de4112c75af0b38fc1946f44e3658ed1890)

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 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 d789110..6386744 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;
 
-- 
2.5.0