ACK/Cmnt: [SRU][F/aws][PATCH v3 0/6] aws: proper fix for c5.18xlarge hibernation issues

[Tim Gardner]

Acked-by: Tim Gardner <tim.gardner at canonical.com>

pr_info() exists in focal/linux-aws. I'm curious why you didn't preserve 
it in patch 2/6 ?

On 5/19/21 9:15 AM, Andrea Righi wrote:
> BugLink: https://bugs.launchpad.net/bugs/1920944
> 
> [Impact]
> 
> In LP: #1918694 we applied a fix and a workaround to solve the
> hibernation issues on c5.18xlarge. The workaround was in the form of a
> SAUCE patch:
> 
>    "UBUNTU: SAUCE: aws: kvm: double the size of hv_clock_boot"
> 
> It looks like we can replace this workaround with a proper fix, by
> applying this patch:
> 
> http://next.patchew.org/Linux/20210414123544.1060604-1-vkuznets@redhat.com/
> 
> [Test plan]
> 
> Create a c5.18xlarge instance, run the memory stress test script (the
> same test script that we are using to stress test hibernation), trigger
> the hibernate event, trigger the resume event. Repeat a couple of times
> and the problem is very likely to happen.
> 
> [Fix]
> 
> Replace "UBUNTU: SAUCE: aws: kvm: double the size of hv_clock_boot"
> with:
> 
> http://next.patchew.org/Linux/20210414123544.1060604-1-vkuznets@redhat.com/
> 
> The fix has been tested extensively in the AWS infrastructure with
> positive results.
> 
> [Where problems could occur]
> 
> This new code introduced by the fix can be executed also when a CPU is
> put offline, so we may see potential regressions in the KVM CPU
> hotplugging.
> 
> ----------------------------------------------------------------
> Changelog (v2 -> v3):
>   - updated backported / signed-off lines with the right upstream info
>     (thanks Guilherme!)
> 
> NOTE: backport activity was minimal, it only required some context
> adjustments to properly apply the changes.
> 
> Andrea Righi (1):
>        Revert "UBUNTU: SAUCE: aws: kvm: double the size of hv_clock_boot"
> 
> Vitaly Kuznetsov (5):
>        x86/kvm: Fix pr_info() for async PF setup/teardown
>        x86/kvm: Teardown PV features on boot CPU as well
>        x86/kvm: Disable kvmclock on all CPUs on shutdown
>        x86/kvm: Disable all PV features on crash
>        x86/kvm: Unify kvm_pv_guest_cpu_reboot() with kvm_guest_cpu_offline()
> 
>   arch/x86/include/asm/kvm_para.h |   9 ++----
>   arch/x86/kernel/kvm.c           | 113 ++++++++++++++++++++++++++++++++++++++++++++----------------------
>   arch/x86/kernel/kvmclock.c      |  28 ++---------------
>   3 files changed, 79 insertions(+), 71 deletions(-)
> 
> 

-- 
-----------
Tim Gardner
Canonical, Inc