Re: [PATCH v3] vfio-pci: Provide reviewers and acceptance criteria for vendor drivers

[Yishai Hadas <yishaih@nvidia.com>]

On 3/14/2022 10:24 PM, Alex Williamson wrote:
> Vendor or device specific extensions for devices exposed to userspace
> through the vfio-pci-core library open both new functionality and new
> risks.  Here we attempt to provided formalized requirements and
> expectations to ensure that future drivers both collaborate in their
> interaction with existing host drivers, as well as receive additional
> reviews from community members with experience in this area.
>
> Cc: Jason Gunthorpe <jgg@nvidia.com>
> Cc: Yishai Hadas <yishaih@nvidia.com>
> Cc: Kevin Tian <kevin.tian@intel.com>
> Acked-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Reviewed-by: Yishai Hadas <yishaih@nvidia.com>

> ---
>
> v3:
>
> Relocate to Documentation/driver-api/
> Include index.rst reference
> Cross link from maintainer-entry-profile
> Add Shameer's Ack
>
> v2:
>
> Added Yishai
>
> v1:
>
> Per the proposal here[1], I've collected those that volunteered and
> those that I interpreted as showing interest (alpha by last name).  For
> those on the reviewers list below, please R-b/A-b to keep your name as a
> reviewer.  More volunteers are still welcome, please let me know
> explicitly; R-b/A-b will not be used to automatically add reviewers but
> are of course welcome.  Thanks,
>
> Alex
>
> [1]https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fall%2F20220310134954.0df4bb12.alex.williamson%40redhat.com%2F&amp;data=04%7C01%7Cyishaih%40nvidia.com%7Cf97af54aedc341708d6f08da05f8b34b%7C43083d15727340c1b7db39efd9ccc17a%7C0%7C0%7C637828862983240522%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=aQQY6NWJ65p%2B6nyzMXu9VUpOFi1ZClrSW0fQZbLWuoE%3D&amp;reserved=0
>
>   Documentation/driver-api/index.rst                 |    1 +
>   .../vfio-pci-vendor-driver-acceptance.rst          |   35 ++++++++++++++++++++
>   .../maintainer/maintainer-entry-profile.rst        |    1 +
>   MAINTAINERS                                        |   10 ++++++
>   4 files changed, 47 insertions(+)
>   create mode 100644 Documentation/driver-api/vfio-pci-vendor-driver-acceptance.rst
>
> diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst
> index c57c609ad2eb..da1372c8ec3d 100644
> --- a/Documentation/driver-api/index.rst
> +++ b/Documentation/driver-api/index.rst
> @@ -103,6 +103,7 @@ available subsections can be seen below.
>      sync_file
>      vfio-mediated-device
>      vfio
> +   vfio-pci-vendor-driver-acceptance
>      xilinx/index
>      xillybus
>      zorro
> diff --git a/Documentation/driver-api/vfio-pci-vendor-driver-acceptance.rst b/Documentation/driver-api/vfio-pci-vendor-driver-acceptance.rst
> new file mode 100644
> index 000000000000..3a108d748681
> --- /dev/null
> +++ b/Documentation/driver-api/vfio-pci-vendor-driver-acceptance.rst
> @@ -0,0 +1,35 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +Acceptance criteria for vfio-pci device specific driver variants
> +================================================================
> +
> +Overview
> +--------
> +The vfio-pci driver exists as a device agnostic driver using the
> +system IOMMU and relying on the robustness of platform fault
> +handling to provide isolated device access to userspace.  While the
> +vfio-pci driver does include some device specific support, further
> +extensions for yet more advanced device specific features are not
> +sustainable.  The vfio-pci driver has therefore split out
> +vfio-pci-core as a library that may be reused to implement features
> +requiring device specific knowledge, ex. saving and loading device
> +state for the purposes of supporting migration.
> +
> +In support of such features, it's expected that some device specific
> +variants may interact with parent devices (ex. SR-IOV PF in support of
> +a user assigned VF) or other extensions that may not be otherwise
> +accessible via the vfio-pci base driver.  Authors of such drivers
> +should be diligent not to create exploitable interfaces via such
> +interactions or allow unchecked userspace data to have an effect
> +beyond the scope of the assigned device.
> +
> +New driver submissions are therefore requested to have approval via
> +Sign-off/Acked-by/etc for any interactions with parent drivers.
> +Additionally, drivers should make an attempt to provide sufficient
> +documentation for reviewers to understand the device specific
> +extensions, for example in the case of migration data, how is the
> +device state composed and consumed, which portions are not otherwise
> +available to the user via vfio-pci, what safeguards exist to validate
> +the data, etc.  To that extent, authors should additionally expect to
> +require reviews from at least one of the listed reviewers, in addition
> +to the overall vfio maintainer.
> diff --git a/Documentation/maintainer/maintainer-entry-profile.rst b/Documentation/maintainer/maintainer-entry-profile.rst
> index 5d5cc3acdf85..8b4971c7e3fa 100644
> --- a/Documentation/maintainer/maintainer-entry-profile.rst
> +++ b/Documentation/maintainer/maintainer-entry-profile.rst
> @@ -103,3 +103,4 @@ to do something different in the near future.
>      ../nvdimm/maintainer-entry-profile
>      ../riscv/patch-acceptance
>      ../driver-api/media/maintainer-entry-profile
> +   ../driver-api/vfio-pci-vendor-driver-acceptance
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 4322b5321891..fd17d1891216 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -20314,6 +20314,16 @@ F:	drivers/vfio/mdev/
>   F:	include/linux/mdev.h
>   F:	samples/vfio-mdev/
>   
> +VFIO PCI VENDOR DRIVERS
> +R:	Jason Gunthorpe <jgg@nvidia.com>
> +R:	Yishai Hadas <yishaih@nvidia.com>
> +R:	Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> +R:	Kevin Tian <kevin.tian@intel.com>
> +L:	kvm@vger.kernel.org
> +S:	Maintained
> +P:	Documentation/driver-api/vfio-pci-vendor-driver-acceptance.rst
> +F:	drivers/vfio/pci/*/
> +
>   VFIO PLATFORM DRIVER
>   M:	Eric Auger <eric.auger@redhat.com>
>   L:	kvm@vger.kernel.org
>
>