Re: [Qemu-devel] [PATCH 1/2] pci: Add pci_device_get_host_irq

[Jan Kiszka]

On 2012-06-01 18:05, Michael S. Tsirkin wrote:
> On Fri, Jun 01, 2012 at 05:54:15PM +0200, Jan Kiszka wrote:
>> On 2012-06-01 17:28, Michael S. Tsirkin wrote:
>>>>> So I won't object to adding a new API but if we do
>>>>> it properly this won't help compatibility :(
>>>>
>>>> It will as this API does not touch the parts that affect the vmstate
>>>> (ie. semantics of irq_count won't change).
>>>
>>> Yes but irq_count in vmstate is a bug. IMO even if we do
>>> not change anything we should ignore irq_count on
>>> load and recalculate it from what the devices supply.
>>
>> I don't disagree. But this will only allow keeping backward migration
>> support if we preserve the semantics of current map_irq somewhere - to
>> keep the chance of calculating the legacy values for vmsave as well.
>>
>> Jan
> 
> We don't need to preserve it, right? We can calculate it before
> savevm.

We can't calculate it without something like the additional
infrastructure I listed.

Jan

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