Re: [PATCH v4 0/4] virtio: Clean up scatterlists and use the DMA API

Jan Kiszka
2015-07-29T08:20:34Z

On 2015-07-29 10:17, Paolo Bonzini wrote:
>
>
> On 29/07/2015 02:47, Andy Lutomirski wrote:
>>>> If new kernels ignore the IOMMU for devices that don't set the flag
>>>> and there are physical devices that already exist and don't set the
>>>> flag, then those devices won't work reliably on most modern
>>>> non-virtual platforms, PPC included.
>>>
>>> Are there many virtio physical devices out there ? We are talking about
>>> a virtio flag right ? Or have you been considering something else ?
>>
>> Yes, virtio flag. I dislike having a virtio flag at all, but so far
>> no one has come up with any better ideas. If there was a reliable,
>> cross-platform mechanism for per-device PCI bus properties, I'd be all
>> for using that instead.
>
> No, a virtio flag doesn't make sense.

That will create the risk of subtly breaking old guests over new setups.
I wouldn't suggest this.

Jan

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