Re: [PATCH v10 11/11] vfio: Document nested stage control

[Zenghui Yu]

Hi Eric,

On 2020/3/21 0:19, Eric Auger wrote:
> The VFIO API was enhanced to support nested stage control: a bunch of
> new iotcls, one DMA FAULT region and an associated specific IRQ.
>
> Let's document the process to follow to set up nested mode.
>
> Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>

[...]

> +The userspace must be prepared to receive faults. The VFIO-PCI device
> +exposes one dedicated DMA FAULT region: it contains a ring buffer and
> +its header that allows to manage the head/tail indices. The region is
> +identified by the following index/subindex:
> +- VFIO_REGION_TYPE_NESTED/VFIO_REGION_SUBTYPE_NESTED_DMA_FAULT
> +
> +The DMA FAULT region exposes a VFIO_REGION_INFO_CAP_PRODUCER_FAULT
> +region capability that allows the userspace to retrieve the ABI version
> +of the fault records filled by the host.

Nit: I don't see this capability in the code.


Thanks,
Zenghui