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

[Jan Kiszka]

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

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