Re: [Qemu-devel] [PATCH 2/5] pc: hack for migration compatibility from QEMU 2.0

[Paolo Bonzini]

Il 28/07/2014 17:05, Michael S. Tsirkin ha scritto:
>> > +/* These are used to size the ACPI tables for -M pc-i440fx-1.7 and
>> > + * -M pc-i440fx-2.0.  Even if the actual amount of AML generated grows
>> > + * a little bit, there should be plenty of free space since the DSDT
>> > + * shrunk by ~1.5k between QEMU 2.0 and QEMU 2.1.
>> > + */
>> > +#define ACPI_BUILD_LEGACY_CPU_AML_SIZE    97
>> > +#define ACPI_BUILD_LEGACY_BRIDGE_AML_SIZE 1872
> 
> Hmm this is wrong if some slot is occupied by a
> non hotpluggable device, is it not?

I honestly have no idea.  If even more complicated code is needed, I'd
rather get rid of all this bridge stuff altogether (as far as computing
the AML size goes), and declare 2.0->2.1 migration broken if the VM has
bridges.

Paolo