colo: Fix crash during device vmstate load
With colo we load device vmstate during each checkpoint, on top of a vm that was already running. Some devices expect a reset before loading vmstate on such a previously running vm. This fixes a crash when using COLO with Q35 machine. The reset adds 10-20ms overhead to the checkpointing proces in my testing. Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Lukas Straub <lukasstraub2@web.de> Link: https://lore.kernel.org/qemu-devel/20260302-colo_unit_test_multifd-v11-10-d653fb3b1d80@web.de Signed-off-by: Fabiano Rosas <farosas@suse.de>
Lukas Straub committed
Mar 2, 2026 at 12:45 UTC
32603ba372266f9a32cd56f4c5d7137ea00fdf15
1 file changed
+6
migration/colo.c
+6
@@ -729,6 +729,12 @@ static void colo_incoming_process_checkpoint(MigrationIncomingState *mis,
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bql_lock();
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vmstate_loading = true;
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+ /*
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+ * With colo we load device vmstate during each checkpoint, on top of
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+ * a vm that was already running. Some devices expect a reset before
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+ * loading vmstate on such a previously running vm.
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+ */
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+ qemu_system_reset(SHUTDOWN_CAUSE_SNAPSHOT_LOAD);
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colo_flush_ram_cache();
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ret = qemu_load_device_state(fb, errp);
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if (ret < 0) {