Re: [PATCH v9 00/12] Add Mediated device support
From: Alex Williamson
Date: Mon Oct 17 2016 - 17:41:09 EST
On Tue, 18 Oct 2016 02:52:00 +0530
Kirti Wankhede <kwankhede@xxxxxxxxxx> wrote:
> This series adds Mediated device support to Linux host kernel. Purpose
> of this series is to provide a common interface for mediated device
> management that can be used by different devices. This series introduces
> Mdev core module that creates and manages mediated devices, VFIO based
> driver for mediated devices that are created by mdev core module and
> update VFIO type1 IOMMU module to support pinning & unpinning for mediated
> What changed in v9?
> - added class named 'mdev_bus' that contains links to devices that are
> registered with the mdev core driver.
> - The [<type-id>] name is created by adding the the device driver string as a
> prefix to the string provided by the vendor driver.
> - 'device_api' attribute should be provided by vendor driver and should show
> which device API is being created, for example, "vfio-pci" for a PCI device.
> - Renamed link to its type in mdev device directory to 'mdev_type'
> - Split commits in multple individual commits
> - Added function to get device_api string based on vfio_device_info.flags.
> - Handled the case if all devices attached to the normal IOMMU API domain
> go away and mdev device still exist in domain. Updated page accounting
> for local domain.
> - Similarly if device is attached to normal IOMMU API domain, mappings are
> establised and page accounting is updated accordingly.
> - Tested hot-plug and hot-unplug of vGPU and GPU pass through device with
> Linux VM.
I also commented that there must be an invalidation mechanism for pages
pinned by the vendor driver. This is where pfn pinning was adjusting
accounting after a DMA_MAP, where the pfn should have been invalidated
on user unmap. Userspace is in control of page mappings, the vendor
driver cannot maintain references to pages unmapped by the user. I
would suggest that minimally some sort of callback needs to be
registered for every set of pinned pages to be called when the user
unmaps those IOVAs. Thanks,
> - Updated Documentation and sample driver, mtty.c, accordingly.
> Kirti Wankhede (12):
> vfio: Mediated device Core driver
> vfio: VFIO based driver for Mediated devices
> vfio: Rearrange functions to get vfio_group from dev
> vfio iommu: Add support for mediated devices
> vfio: Introduce common function to add capabilities
> vfio_pci: Update vfio_pci to use vfio_info_add_capability()
> vfio: Introduce vfio_set_irqs_validate_and_prepare()
> vfio_pci: Updated to use vfio_set_irqs_validate_and_prepare()
> vfio_platform: Updated to use vfio_set_irqs_validate_and_prepare()
> vfio: Add function to get device_api string from
> docs: Add Documentation for Mediated devices
> docs: Sample driver to demonstrate how to use Mediated device
> Documentation/vfio-mdev/Makefile | 13 +
> Documentation/vfio-mdev/mtty.c | 1429 ++++++++++++++++++++++
> Documentation/vfio-mdev/vfio-mediated-device.txt | 389 ++++++
> drivers/vfio/Kconfig | 1 +
> drivers/vfio/Makefile | 1 +
> drivers/vfio/mdev/Kconfig | 18 +
> drivers/vfio/mdev/Makefile | 5 +
> drivers/vfio/mdev/mdev_core.c | 372 ++++++
> drivers/vfio/mdev/mdev_driver.c | 128 ++
> drivers/vfio/mdev/mdev_private.h | 41 +
> drivers/vfio/mdev/mdev_sysfs.c | 296 +++++
> drivers/vfio/mdev/vfio_mdev.c | 148 +++
> drivers/vfio/pci/vfio_pci.c | 101 +-
> drivers/vfio/platform/vfio_platform_common.c | 31 +-
> drivers/vfio/vfio.c | 287 ++++-
> drivers/vfio/vfio_iommu_type1.c | 692 +++++++++--
> include/linux/mdev.h | 177 +++
> include/linux/vfio.h | 23 +-
> 18 files changed, 3948 insertions(+), 204 deletions(-)
> create mode 100644 Documentation/vfio-mdev/Makefile
> create mode 100644 Documentation/vfio-mdev/mtty.c
> create mode 100644 Documentation/vfio-mdev/vfio-mediated-device.txt
> create mode 100644 drivers/vfio/mdev/Kconfig
> create mode 100644 drivers/vfio/mdev/Makefile
> create mode 100644 drivers/vfio/mdev/mdev_core.c
> create mode 100644 drivers/vfio/mdev/mdev_driver.c
> create mode 100644 drivers/vfio/mdev/mdev_private.h
> create mode 100644 drivers/vfio/mdev/mdev_sysfs.c
> create mode 100644 drivers/vfio/mdev/vfio_mdev.c
> create mode 100644 include/linux/mdev.h