Igor Mammedov d96c4d5f19 vl.c: fix migration failure for 3.1 and older machine types ... Migration from QEMU(v4.0) fails when using 3.1 or older machine type. For example if one attempts to migrate QEMU-2.12 started as qemu-system-ppc64 -nodefaults -M pseries-2.12 -m 4096 -mem-path /tmp/ to current master, it will fail with qemu-system-ppc64: Unknown ramblock "ppc_spapr.ram", cannot accept migration qemu-system-ppc64: error while loading state for instance 0x0 of device 'ram' qemu-system-ppc64: load of migration failed: Invalid argument Caused by 900c0ba373 commit which switches main RAM allocation to memory backends and the fact in 3.1 and older QEMU, backends used full[***] QOM path as memory region name instead of backend's name. That was changed after 3.1 to use prefix-less names by default (fa0cb34d22) for new machine types. *** effectively makes main RAM memory region names defined by MachineClass::default_ram_id being altered with '/objects/' prefix and therefore migration fails as old QEMU sends prefix-less name while new QEMU expects name with prefix when using 3.1 and older machine types. Fix it by forcing implicit[1] memory backend to always use prefix-less names for its memory region by setting 'x-use-canonical-path-for-ramblock-id' property to false. 1) i.e. memory backend created by compat glue which maps -m/-mem-path/-mem-prealloc/default RAM size into appropriate backend type/options to match old CLI format. Fixes: 900c0ba373 Signed-off-by: Igor Mammedov <imammedo@redhat.com> Reported-by: Lukáš Doktor <ldoktor@redhat.com> Message-Id: <20200304172748.15338-1-imammedo@redhat.com> Tested-by: Lukáš Doktor <ldoktor@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>		2020-03-25 12:31:38 +00:00
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main.c
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vl.c	vl.c: fix migration failure for 3.1 and older machine types	2020-03-25 12:31:38 +00:00