On 09/03/2017 10:58, Jason Wang wrote:
>
>
> On 2017年03月09日 17:28, Igor Mammedov wrote:
>> On Thu, 9 Mar 2017 10:32:44 +0800
>> Jason Wang<jasow...@redhat.com> wrote:
>>
>>> On 2017年03月09日 00:40, Igor Mammedov wrote:
>>>> On Tue, 7 Mar 2017 14:47:30 +0200
>>>> Marcel Apfelbaum<mar...@redhat.com> wrote:
>>>>
>>>>> On 03/07/2017 11:09 AM, Jason Wang wrote:
>>>>>> After commit 96a8821d2141 ("virtio: unbreak virtio-pci with IOMMU
>>>>>> after caching ring translations"), IOMMU was required to be
>>>>>> created in
>>>>>> advance. This is because we can only get the correct dma_as after pci
>>>>>> IOMMU (e.g intel_iommu) was initialized. This is suboptimal and
>>>>>> inconvenient for user. This patch releases this by:
>>>>>>
>>>>>> - introduce a bus_master_ready method for PCIDeviceClass and trigger
>>>>>> this during pci_init_bus_master
>>>>>> - implement virtio-pci method and 1) reset the dma_as 2) re-register
>>>>>> the memory listener to the new dma_as
>> Instead of trying to fix up later it's possible to refuse
>> adding iommu device if other devices has been added before
>> it with -device/device_add.
>> That would match current CLI semantics where device that
>> others depend on should be listed on CLI before that others
>> are listed.
>
> Yes, but it works by chance in the past for the device that does not
> want bus_master_as in their realize. This change may surprise their users.
There is another posssibility. Create the address space at init time
and add a container region instead of the bus_master_enable_region
alias. Then at machine_done time you create the bus_master_enable_region.
This removes the need for the callbacks and makes the MemoryListener
just work.
Paolo
