Subject: Re: [PATCH v11 10/22] vfio iommu type1: Add support for mediated
 devices
To: Kirti Wankhede <kwankhede@nvidia.com>, alex.williamson@redhat.com,
        pbonzini@redhat.com, kraxel@redhat.com, cjia@nvidia.com
References: <1478293856-8191-1-git-send-email-kwankhede@nvidia.com>
 <1478293856-8191-11-git-send-email-kwankhede@nvidia.com>
Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, kevin.tian@intel.com,
        jike.song@intel.com, bjsdjshi@linux.vnet.ibm.com,
        linux-kernel@vger.kernel.org
From: Alexey Kardashevskiy <aik@ozlabs.ru>
Message-ID: <93c0ace9-bf1f-3d94-56ab-3513f7183a1b@ozlabs.ru>
Date: Tue, 8 Nov 2016 17:52:47 +1100
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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