Re: [Qemu-devel] [PATCH qemu v6 12/15] spapr_vfio_pci: Remove redundant spapr-pci-vfio-host-bridge

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 04/22/2015 04:47 PM, David Gibson wrote:
> On Sat, Apr 11, 2015 at 01:24:41AM +1000, Alexey Kardashevskiy wrote:
>> sPAPRTCETable is handling 2 TCE tables already:
>>
>> 1) guest view of the TCE table - emulated devices use only this table;
>>
>> 2) hardware IOMMU table - VFIO PCI devices use it for actual work but
>> it does not replace 1) and it is not visible to the guest.
>> The initialization of this table is driven by vfio-pci device,
>> DMA map/unmap requests are handled via MemoryListener so there is very
>> little to do in spapr-pci-vfio-host-bridge.
>>
>> This moves VFIO bits to the generic spapr-pci-host-bridge which allows
>> putting emulated and VFIO devices on the same PHB. It is still possible
>> to create multiple PHBs and avoid sharing PHB resouces for emulated and
>> VFIO devices.
>>
>> If there is no VFIO-PCI device attaches, no special ioctls will be called.
>> If there are some VFIO-PCI devices attached, PHB may refuse to attach
>> another VFIO-PCI device if a VFIO container on the host kernel side
>> does not support
>> container sharing.
>>
>> This changes spapr-pci-host-bridge to support properties of
>> spapr-pci-vfio-host-bridge. This makes spapr-pci-vfio-host-bridge type
>> equal to spapr-pci-host-bridge.
>>
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>
> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
>
>> ---
>>
>> How do create aliases for types?
>
> ^^ I assume this is left over from some notes of your own?

Nope, this is a question to the public. I ended up having 2 different QOM 
types (one is derived from another and has an extra property - "iommuid") 
while I could (probably) have just one (spapr-pci-host-bridge) and the 
other (spapr-pci-vfio-host-bridge) would be an alias as we have aliases for 
machines (when "pseries" is an alias for "pseries-2.3", etc). I am fine 
with the existing approach as it does not add new property to 
spapr-pci-host-bridge (otherwise it would have to), but still.



-- 
Alexey