spapr: Fix migration of PCI host bridges from qemu-2.7
daa23699 "spapr_pci: Add a 64-bit MMIO window" subtly broke migration from qemu-2.7 to the current version. It split the device's MMIO window into two pieces for 32-bit and 64-bit MMIO. The patch included backwards compatibility code to convert the old property into the new format. However, the property value was also transferred in the migration stream and compared with a (probably unwise) VMSTATE_EQUAL. So, the "raw" value from 2.7 is compared to the new style converted value from (pre-)2.8 giving a mismatch and migration failure. Although it would be technically possible to fix this in a way allowing backwards migration, that would leave an ugly legacy around indefinitely. This patch takes the simpler approach of bumping the migration version, dropping the unwise VMSTATE_EQUAL (and some equally unwise ones around it) and ignoring them on an incoming migration. Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au> Reviewed-by: NAlexey Kardashevskiy <aik@ozlabs.ru>
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