Re: [Qemu-devel] [PATCH v11 10/22] vfio iommu type1: Add support for mediated devices

[Alexey Kardashevskiy]

On 05/11/16 08:10, Kirti Wankhede wrote:
> VFIO IOMMU drivers are designed for the devices which are IOMMU capable.
> Mediated device only uses IOMMU APIs, the underlying hardware can be
> managed by an IOMMU domain.
> 
> Aim of this change is:
> - To use most of the code of TYPE1 IOMMU driver for mediated devices
> - To support direct assigned device and mediated device in single module
> 
> This change adds pin and unpin support for mediated device to TYPE1 IOMMU
> backend module. More details:
> - vfio_pin_pages() callback here uses task and address space of vfio_dma,
>   that is, of the process who mapped that iova range.
> - Added pfn_list tracking logic to address space structure. All pages
>   pinned through this interface are trached in its address space.
> - Pinned pages list is used to verify unpinning request and to unpin
>   remaining pages while detaching the group for that device.
> - Page accounting is updated to account in its address space where the
>   pages are pinned/unpinned.
> -  Accouting for mdev device is only done if there is no iommu capable
>   domain in the container. When there is a direct device assigned to the
>   container and that domain is iommu capable, all pages are already pinned
>   during DMA_MAP.
> - Page accouting is updated on hot plug and unplug mdev device and pass
>   through device.
> 
> Tested by assigning below combinations of devices to a single VM:
> - GPU pass through only

This does not require this patchset, right?

> - vGPU device only

Out of curiosity - how exactly did you test this? The exact GPU, how to
create vGPU, what was the QEMU command line and the guest does with this
passed device? Thanks.




-- 
Alexey