Re: [Qemu-devel] [PATCH qemu v7 06/14] spapr_iommu: Introduce "enabled" state for TCE table

[Paolo Bonzini <pbonzini@redhat.com>]

On 04/07/2015 03:12, Alexey Kardashevskiy wrote:
>>
>>> One step back :) Whole dance is what here? There are:
>>> 1) del+set_size(0)
>>> 2) set_size(not zero)+add
>>
>> Then no need for begin/commit. :)
> 
> I got a new problem here - set_size(0) + set_size(not 0) do not invoke
> region_del/region_add which does not seem right. As the result,
> vfio_listener_region_del() never gets called and the IOMMU MR notifier
> stays in the container->giommu_list. What is the correct solution to this?
> 
> Incorrect (most likely :) ) solution is in
> [PATCH qemu v9 13/13] spapr_pci/spapr_pci_vfio: Support Dynamic DMA
> Windows (DDW)
> where I explicitely do  memory_region_del_subregion() +
> memory_region_add_subregion() which seems to do the right job.

I would like a comment there explaining the problem (i.e. what you would
have done, what you expected and what were the actual results: it's not
even that clear from this email), but it doesn't seem like an awful
thing to do.

Paolo