[SRU][Mantic][PATCH 0/1] UBUNTU: SAUCE: Add mdev_set_iommu_device() kABI

[Tarun Gupta]

BugLink : https://bugs.launchpad.net/bugs/1988806

SRU Justification:

[Impact]

Currently, with below commit present in 5.16 upstream kernel,
mdev_set_iommu_device() kABI is removed.

 fda49d97f2c4 ("vfio: remove the unused mdev iommu hook")

This results in SRIOV based Nvidia vGPU being broken with kernels that
have the above upstream commit present.
So, with Ubuntu 22.04 HWE kernel update (i.e the 6.5.x Mantic kernel),
SRIOV based Nvidia vGPU is broken.

Earlier, during Kinetic and Lunar release, a similar patch
was accepted. Refer
https://lists.ubuntu.com/archives/kernel-team/2022-September/133142.html 
https://lists.ubuntu.com/archives/kernel-team/2023-May/139578.html

[Fix]

On 6.5.x HWE kernel, we revert the above patch which removed the support
for mdev_set_iommu_device() kABI so that vGPU works fine.

Separately, to fix this in upstream kernels, vGPU will adopt
vfio-pci-core framework instead of using MDEV framework.
In Ubuntu 24.04 LTS onwards, we don't need this custom patch as vGPU
will use vfio-pci-framework. This should be the last Ubuntu release that
requires this custom mdev patch.

[Testcase]

Run SRIOV based (Ampere+) Nvidia vGPU on 6.5.x (Mantic) kernel.


Tarun Gupta (1):
  UBUNTU: SAUCE: Add mdev_set_iommu_device() kABI

 drivers/vfio/mdev/mdev_driver.c  |   1 +
 drivers/vfio/mdev/mdev_private.h |   1 -
 drivers/vfio/vfio_iommu_type1.c  | 127 ++++++++++++++++++++++++++++---
 include/linux/mdev.h             |  22 ++++++
 4 files changed, 141 insertions(+), 10 deletions(-)

-- 
2.31.1