[SRU][G/aws][PULL] aws: update Xen hibernation patch set

[Stefan Bader]

On 24.02.21 15:41, Andrea Righi wrote:
> BugLink: https://bugs.launchpad.net/bugs/1913410
> BugLink: https://bugs.launchpad.net/bugs/1906850

I have not looked into the actual pull request but if it contains the second bug
report as an active reference this might lead to confusion. The whole system
around bug references in launchpad not really is up for going backwards. And for
Focal the status is fix-released. When we apply the replacements and release
them everything will go through verification and release messages there again.

So for G its probably ok to keep it active, for F there should not be a change
related to the second bug report before and after, so I would probably change
that commit to only use BugLink for the new refresh bug (maybe keep the old one
as "OldBug:" or whatever as long as it is not BugLink.

And for B you would have to add that nomination to the second bug.

-Stefan
> 
> [Impact]
> 
> Amazon maintains a custom kernel patch set to properly support
> hibernation in Xen.
> 
> This patch set is available in the amazonlinux kernel git repository:
> https://github.com/amazonlinux/linux.git
> 
> It is important to periodically re-sync our version of this patch set
> with the new versions that are pushed by Amazon and make sure we include
> all the required patches and drop the old ones.
> 
> This pull request is a revert of the old xen/hibernation patch set +
> applying the new patch set.
> 
> Many of these patches required a small backporting activity, mostly due
> to context adjustments (no functional changes).
> 
> [Test case]
> 
> A test kernel with this new patch set applied has been extensively
> tested in the AWS cloud both by our testing scripts (multiple
> hibernation/resume cycles) and by Amazon with positive results.
> 
> [Fix]
> 
> Revert the old xen/hibernation patch set + apply the new patch set.
> 
> [Regression potential]
> 
> All the changes are touching the Xen (guest) code and hibernation,
> so we can only see potential regressions in these subsystems.
> 
> --
> 
> The following changes since commit 497a6691ca053fcb53b0a971317be9736c54f675:
> 
>   UBUNTU: Ubuntu-aws-5.8.0-1024.26 (2021-02-10 15:04:42 -0600)
> 
> are available in the Git repository at:
> 
>   git://git.launchpad.net/~arighi/ubuntu/+source/linux-aws/+git/groovy f7396c3d5475959ae21011425f39bcaf02cb91f1
> 
> for you to fetch changes up to f7396c3d5475959ae21011425f39bcaf02cb91f1:
> 
>   UBUNTU: SAUCE: x86: tsc: avoid system instability in hibernation (2021-02-24 15:10:41 +0100)
> 
> ----------------------------------------------------------------
> Anchal Agarwal (3):
>       UBUNTU: SAUCE: x86/xen: Introduce new function to map HYPERVISOR_shared_info on Resume
>       UBUNTU: SAUCE: xen: Introduce wrapper for save/restore sched clock offset
>       UBUNTU: SAUCE: xen: Update sched clock offset to avoid system instability in hibernation
> 
> Andrea Righi (11):
>       Revert "UBUNTU: SAUCE: xen: Update sched clock offset to avoid system instability in hibernation"
>       Revert "UBUNTU: SAUCE: xen: Introduce wrapper for save/restore sched clock offset"
>       Revert "UBUNTU: SAUCE: x86/xen: save and restore steal clock"
>       Revert "UBUNTU: SAUCE: xen/time: introduce xen_{save,restore}_steal_clock"
>       Revert "UBUNTU: SAUCE: xen-netfront: add callbacks for PM suspend and hibernation"
>       Revert "UBUNTU: SAUCE: xen-blkfront: add callbacks for PM suspend and hibernation"
>       Revert "UBUNTU: SAUCE: x86/xen: add system core suspend and resume callbacks"
>       Revert "UBUNTU: SAUCE: x86/xen: Introduce new function to map HYPERVISOR_shared_info on Resume"
>       Revert "UBUNTU: SAUCE: xenbus: add freeze/thaw/restore callbacks support"
>       Revert "UBUNTU: SAUCE: xen/manage: keep track of the on-going suspend mode"
>       UBUNTU: SAUCE: xen-netfront: prevent unnecessary close on hibernate
> 
> Eduardo Valentin (1):
>       UBUNTU: SAUCE: x86: tsc: avoid system instability in hibernation
> 
> Munehisa Kamata (7):
>       UBUNTU: SAUCE: xen/manage: keep track of the on-going suspend mode
>       UBUNTU: SAUCE: xenbus: add freeze/thaw/restore callbacks support
>       UBUNTU: SAUCE: x86/xen: add system core suspend and resume callbacks
>       UBUNTU: SAUCE: xen-netfront: add callbacks for PM suspend and hibernation support
>       UBUNTU: SAUCE: xen-blkfront: add callbacks for PM suspend and hibernation
>       UBUNTU: SAUCE: xen/time: introduce xen_{save,restore}_steal_clock
>       UBUNTU: SAUCE: x86/xen: save and restore steal clock
> 
>  arch/x86/kernel/tsc.c             | 29 +++++++++++++++++++
>  drivers/block/xen-blkfront.c      | 61 +++++++++++++++++++--------------------
>  drivers/net/xen-netfront.c        | 11 ++++++-
>  drivers/xen/xenbus/xenbus_probe.c | 19 ++++++------
>  include/linux/sched/clock.h       |  5 ++++
>  kernel/sched/clock.c              |  4 +--
>  6 files changed, 86 insertions(+), 43 deletions(-)
>