ACK: [SRU][jammy:linux-azure][PATCH 0/3] Ubuntu 20.04 confidential VM deployments are failing

[Aaron Jauregui]

On Mon, Jan 27, 2025 at 08:20:34PM -0600, John Cabaj wrote:
> BugLink: https://bugs.launchpad.net/bugs/2096813
> 
> SRU Justification
> 
> [Impact]
> 
> * 20.04 Azure CVM (with 5.15 kernel) instances are failing to boot with high reproducibility
> 
> [Fix]
> 
> * Clean reverts of the following commits:
> * 8bd834015a5e: "UBUNTU: SAUCE: swiotlb: Split up single swiotlb lock"
> * 3db34e258474: "UBUNTU: SAUCE: swiotlb: allocate memory in a cache-friendly way"
> * 9e1b646a9cac: "UBUNTU: SAUCE: swiotlb: use bitmap to track free slots"
> 
> [Test Plan]
> 
> * Compile tested
> * Boot tested
> * Tested with Azure images, booted successfully 25 consecutive times
> 
> [Regression potential]
> 
> * Changes isolated, minimal regression risk. Changes were SAUCE patches, so reverting back to upstream functionality.
> * Likely small I/O performance hit under heavy I/O, but alleviates system hangs
> 
> [Other info]
> 
> * SF#00405149
> 
> John Cabaj (3):
>   Revert "UBUNTU: SAUCE: swiotlb: Split up single swiotlb lock"
>   Revert "UBUNTU: SAUCE: swiotlb: allocate memory in a cache-friendly
>     way"
>   Revert "UBUNTU: SAUCE: swiotlb: use bitmap to track free slots"
> 
>  .../admin-guide/kernel-parameters.txt         |   4 +-
>  arch/x86/kernel/acpi/boot.c                   |   4 -
>  include/linux/swiotlb.h                       |  44 +--
>  kernel/dma/swiotlb.c                          | 280 ++++++------------
>  4 files changed, 102 insertions(+), 230 deletions(-)

Acked-by: Aaron Jauregui <aaron.jauregui at canonical.com>