Re: [Qemu-devel] [PATCH 3/3] apic: always update the in-kernel status after loading

[Paolo Bonzini <pbonzini@redhat.com>]

Il 30/10/2012 13:38, Avi Kivity ha scritto:
> On 10/30/2012 02:16 PM, Paolo Bonzini wrote:
>> The LAPIC is loaded separately from the rest of the VCPU state.  Thus,
>> when restoring the CPU the dummy post-reset state is passed to the
>> in-kernel APIC.
>>
>> This can cause MSI injection to fail if attempted during the restore of
>> another device, because the LAPIC believes it's not enabled.
>>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> ---
>>  hw/apic_common.c |    1 +
>>  1 files changed, 1 insertions(+), 0 deletions(-)
>>
>> diff --git a/hw/apic_common.c b/hw/apic_common.c
>> index f373ba8..1ef52b2 100644
>> --- a/hw/apic_common.c
>> +++ b/hw/apic_common.c
>> @@ -362,6 +362,7 @@ static int apic_dispatch_post_load(void *opaque, int version_id)
>>      if (info->post_load) {
>>          info->post_load(s);
>>      }
>> +    cpu_put_apic_state(DEVICE(s));
>>      return 0;
>>  }
> 
> Aren't we still dependent on the order of processing?  If the APIC is
> restored after the device, won't we get the same problem?

Strictly speaking yes, but CPUs and APICs are always the first devices
to be saved.

Paolo