ACK/cmt: [SRU X][PATCH 0/1] LP: #1802421 - i40e + iommu data corruption

[Khaled Elmously]

On 2018-11-09 12:11:09 , Daniel Axtens wrote:
> A user reports that using an i40e with intel_iommu=on with the Xenial
> GA kernel causes data corruption. Using the Xenial HWE kernel or an
> out-of-tree driver more recent than the version shipped with Xenial
> solves the issue.
> 
> [Impact]
> Corrupted data is returned from the network card intermittently. This
> is often noticeable when using apt, as the checksums are verified. If
> often leads to failure of apt operations. When there are no checksums
> done, this could lead to silent data corruption.
> 
> [Fix]
> This was fixed somewhere post-4.4. Testing identified b32bfa17246d
> ("i40e: Drop packet split receive routine") which is part of a broader
> refactor. Picking this patch alone is sufficient to fix the issue. My
> theory is that iommu exposes an issue in the packet split receive
> routine and so removing it is sufficient to prevent the problem from
> occurring.
> 
> [Test]
> A user tested a Xenial 4.4 kernel with this patch applied and it fixed
> their issue - no data corruption was observed. (The test repeatedly
> deletes the apt cache and then does apt update.)
> 
> [Regression Potential]
> It's a messy change inside i40e, so the risk is that i40e will be
> broken in some subtle way we haven't noticed, or have performance
> issues. None of these have been observed so far.
> 
> 
> Jesse Brandeburg (1):
>   i40e: Drop packet split receive routine
> 
>  drivers/net/ethernet/intel/i40e/i40e.h        |   3 -
>  .../net/ethernet/intel/i40e/i40e_debugfs.c    |   4 +-
>  .../net/ethernet/intel/i40e/i40e_ethtool.c    |  19 --
>  drivers/net/ethernet/intel/i40e/i40e_main.c   |  49 +---
>  drivers/net/ethernet/intel/i40e/i40e_txrx.c   | 244 +-----------------
>  drivers/net/ethernet/intel/i40e/i40e_txrx.h   |   7 -
>  6 files changed, 10 insertions(+), 316 deletions(-)
>

Acked-by: Khalid Elmously <khalid.elmously at canonical.com>