ACK/Cmnt: [SRU][Trusty][PULL] Cleanup Meltdown/Spectre implementation (LP: #1779848)

[Stefan Bader]

On 09.10.18 15:37, Juerg Haefliger wrote:
> BugLink: https://bugs.launchpad.net/bugs/1779848
> 
> == SRU Justification ==
> 
> Ubuntu kernels contain Meltdown and Spectre mitigations that are largely based on embargoed patches but what eventually landed in upstream is different in some places. We should clean up the different kernels to bring them closer in line with upstream.
> 
> == Fix ==
> 
> Add missing upstream patches.
> 
> == Regression Potential ==
> 
> Medium. The patches have been in upstream for quite a while now and are baked in but some of the backporting is not completely trivial and without risk.
> 
> == Test Case ==
> 
> TBD.
> 
> *** BLURB HERE ***
> 
> Signed-off-by: Juerg Haefliger <juergh at canonical.com>
> ---
> 
> The following changes since commit cefa65a1685282dcbadad7c914d4d8e89428a5eb:
> 
>   UBUNTU: Ubuntu-3.13.0-161.211 (2018-10-03 16:41:43 +0200)
> 
> are available in the Git repository at:
> 
>   git://git.launchpad.net/~juergh/+git/trusty-linux lp1779848
> 
> for you to fetch changes up to 8cccec097d1fb83c610f9dddd47827fb6d3237aa:
> 
>   UBUNTU: SAUCE: x86/speculation: Cleanup IBRS runtime control handling (2018-10-09 10:46:55 +0200)
> 
> ----------------------------------------------------------------
> Arnd Bergmann (1):
>       x86/pti: Mark constant arrays as __initconst
> 
> Ben Hutchings (1):
>       xen: Add xen_arch_suspend()
> 
> Borislav Petkov (2):
>       x86/nospec: Fix header guards names
>       x86/bugs: Drop one "mitigation" from dmesg
> 
> Dan Carpenter (1):
>       x86/spectre: Fix an error message
> 
> Dave Hansen (1):
>       x86/Documentation: Add PTI description
> 
> David Woodhouse (5):
>       x86/cpufeatures: Add AMD feature bits for Speculation Control
>       x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support
>       x86/cpufeatures: Clean up Spectre v2 related CPUID flags
>       x86/cpuid: Fix up "virtual" IBRS/IBPB/STIBP feature bits on Intel
>       x86/speculation: Use IBRS if available before calling into firmware
> 
> Dou Liyang (1):
>       x86/spectre: Check CONFIG_RETPOLINE in command line parser
> 
> Ingo Molnar (1):
>       x86/speculation: Move firmware_restrict_branch_speculation_*() from C to CPP
> 
> Juerg Haefliger (14):
>       Revert "x86/cpu/AMD: Make the LFENCE instruction serialized"
>       UBUNTU: SAUCE: x86/cpufeatures: Reorder spectre-related feature bits
>       UBUNTU: SAUCE: x86/msr: Fix formatting of msr-index.h
>       UBUNTU: SAUCE: x86/msr: Rename MSR spec control feature bits
>       UBUNTU: SAUCE: x86/speculation: Use synthetic bits for IBRS/IBPB/STIBP
>       UBUNTU: SAUCE: x86/cpufeatures: Disentangle MSR_SPEC_CTRL enumeration from IBRS
>       UBUNTU: SAUCE: x86/bugs: Fix re-use of SPEC_CTRL MSR boot value
>       UBUNTU: SAUCE: Move SSBD feature detection to common code
>       UBUNTU: SAUCE: x86/speculation: Move vendor specific IBRS/IBPB control code
>       UBUNTU: SAUCE: x86/speculation: Query individual feature flags when reloading microcode
>       UBUNTU: SAUCE: x86/pti: Evaluate X86_BUG_CPU_MELTDOWN when pti=auto
>       UBUNTU: SAUCE: x86/speculation: Make use of indirect_branch_prediction_barrier()
>       UBUNTU: SAUCE: x86/speculation: Cleanup IBPB runtime control handling
>       UBUNTU: SAUCE: x86/speculation: Cleanup IBRS runtime control handling
> 
> Juergen Gross (1):
>       x86/xen: Zero MSR_IA32_SPEC_CTRL before suspend
> 
> KarimAllah Ahmed (1):
>       x86/spectre: Simplify spectre_v2 command line parsing
> 
> Tom Lendacky (2):
>       x86/cpu/AMD: Make LFENCE a serializing instruction
>       x86/cpu/AMD: Use LFENCE_RDTSC in preference to MFENCE_RDTSC
> 
> zhenwei.pi (1):
>       x86/pti: Document fix wrong index
> 
>  Documentation/kernel-parameters.txt   |  21 ++--
>  Documentation/x86/pti.txt             | 186 +++++++++++++++++++++++++++++++++
>  arch/x86/include/asm/apm.h            |   6 ++
>  arch/x86/include/asm/cpufeature.h     |  31 ++++--
>  arch/x86/include/asm/efi.h            |   7 ++
>  arch/x86/include/asm/nospec-branch.h  |  62 ++++++++++-
>  arch/x86/include/asm/spec_ctrl.h      |  13 ++-
>  arch/x86/include/uapi/asm/msr-index.h |  34 +++---
>  arch/x86/kernel/acpi/cstate.c         |   6 +-
>  arch/x86/kernel/cpu/amd.c             |  92 ++++++++--------
>  arch/x86/kernel/cpu/bugs.c            | 169 ++++++++++++++++++++----------
>  arch/x86/kernel/cpu/common.c          |  40 ++++++-
>  arch/x86/kernel/cpu/intel.c           |  19 ----
>  arch/x86/kernel/microcode_core.c      |  20 ----
>  arch/x86/kernel/process.c             |  11 +-
>  arch/x86/kernel/smpboot.c             |   6 +-
>  arch/x86/kvm/svm.c                    |  11 +-
>  arch/x86/kvm/vmx.c                    |   3 +-
>  arch/x86/mm/kaiser.c                  |   7 +-
>  arch/x86/mm/tlb.c                     |   5 +-
>  arch/x86/xen/suspend.c                |  24 +++++
>  drivers/xen/manage.c                  |   9 +-
>  include/linux/smp.h                   |  87 ----------------
>  include/xen/xen-ops.h                 |   1 +
>  kernel/smp.c                          |  46 --------
>  kernel/sysctl.c                       | 191 ++++++++++++++++++++--------------
>  26 files changed, 672 insertions(+), 435 deletions(-)
>  create mode 100644 Documentation/x86/pti.txt
> 

Ok, my main concern was to keep Xenial and Trusty functionally in sync which I
think was confirmed we do, so I guess we should go ahead and pull this in
carefully observe how it goes.

-Stefan


Acked-by: Stefan Bader <stefan.bader at canonical.com>

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