Re: [Qemu-devel] [RFC v3 06/10] virt: Assign a VFIO platform device with -device option

[Eric Auger]

On 06/25/2014 11:30 PM, Alexander Graf wrote:
> 
> On 02.06.14 09:49, Eric Auger wrote:
>> This patch aims at allowing the end-user to specify the device he
>> wants to directly assign to his mach-virt guest in the QEMU command
>> line.
>>
>> The QEMU platform device becomes generic.
>>
>> Current choice is to reuse the "-device" option.
>>
>> For example when assigning Calxeda Midway xgmac device this option
>> is used:
>> -device vfio-platform,vfio_device="fff51000.ethernet",\
>> compat="calxeda/hb-xgmac",mmap-timeout-ms=1000
> 
> I think we're walking into the right direction, but there is one major
> nit I have. I don't think we should have a -device vfio-platform. I
> think we should have a -device vfio-xgmac that maybe inherits from an
> abstrace vfio-platform class.
> 
> That way machine code can assemble the device tree according to the
> device and you can also implement hardware specific hacks or
> dependencies if you need them - for example the MMIO masking to find an
> EOI you did earlier.
I must admit I am lacking experience of other devices than my dear
xgmac. I can just say that for the time beeing the approach seems to fit
some ARM Amba devices like PL330 DMA. We need to go further to identity
the limits of this generic approach.

Best Regards

Eric
> 
> 
> Alex
>