Igor Mammedov <[email protected]> writes:
> On Wed, 27 Mar 2019 16:03:46 +0100
> Markus Armbruster <[email protected]> wrote:
>
>> Recent commit cda4aa9a5a0 moved block backend creation before machine
>> property evaluation. This broke block backends registering migration
>> blockers. Commit e60483f2f84 fixed it by moving migration object
>> creation before block backend creation. This broke migration with
>> Xen. Turns out we need to configure the accelerator before we create
>> the migration object so that Xen's accelerator compat properties get
>> applied. Fix by calling configure_accelerator() earlier, right before
>> migration_object_init().
>>
>> Fixes: e60483f2f8498ae08ae79ca4c6fb03a3317f5e1e
>> Reported-by: Anthony PERARD <[email protected]>
>> Signed-off-by: Markus Armbruster <[email protected]>
>> ---
>> vl.c | 8 ++++++--
>> 1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/vl.c b/vl.c
>> index d61d5604e5..28b9e9a170 100644
>> --- a/vl.c
>> +++ b/vl.c
>> @@ -4276,6 +4276,12 @@ int main(int argc, char **argv, char **envp)
>> exit(0);
>> }
>>
>> + /*
>> + * Must run before migration_object_init() to make Xen's
>> + * accelerator compat properties stick
>> + */
>> + configure_accelerator(current_machine, argv[0]);
>> +
> Setting machine properties with this change happens after
> accelerator was initialized.
>
> It probably will break initialization of accelerator features
> (to name a couple kernel-irqchip, memory-encryption) that depend
> on machine properties being set before accelerator is initialized.
I'm blind. Can you suggest a potential reproducer for me to try?
>> /*
>> * Migration object can only be created after global properties
>> * are applied correctly.
>> @@ -4297,8 +4303,6 @@ int main(int argc, char **argv, char **envp)
>> current_machine->maxram_size = maxram_size;
>> current_machine->ram_slots = ram_slots;
>>
>> - configure_accelerator(current_machine, argv[0]);
>> -
>> if (!qtest_enabled() && machine_class->deprecation_reason) {
>> error_report("Machine type '%s' is deprecated: %s",
>> machine_class->name,
>> machine_class->deprecation_reason);
