[SRU][Bionic][PULL] Update speculation side-channel mitigations

Tyler Hicks tyhicks at canonical.com
Mon Mar 25 21:26:09 UTC 2019

On 2019-03-25 04:58:37, Tyler Hicks wrote:
> Update the speculation side-channel mitigations to match recent upstream
> changes in order to get userspace to userspace protections for Spectre Variant
> 2, a few minor fixes for SSBD, and one that touches code related to Meltdown
> changes.
> STIBP mode will be used conditionally. It will not be used on non-SMT systems.
> It will be used on SMT systems to protect processes that have seccomp filters
> loaded or processes that have used prctl() and the newly defined
> PR_SPEC_INDIRECT_BRANCH argument to opt into STIBP protection.
> Indirect Branch Prediction Barrier (IBPB) will also be used conditionally when
> switching between different userspace tasks and one of the tasks has a seccomp filter loaded or has used prctl() to opt into protection.
> I've tested these patches on SMT and non-SMT systems that I've been using for
> several days without any issues. I've also ran the x86 selftests. Additionally,
> I verified that loading a seccomp filter and/or opting into the mitigations via
> prctl() correctly enables STIBP mode on the SMT system. Finally, I verified
> that the dmesg and /sys/devices/system/cpu/vulnerabilities/* files report the
> correct status when using the "nospectre_v2", "spectre_v2=off",
> "spectre_v2_user=secccomp,ipbp", "spectre_v2_user=on", and
> "spectre_v2_user=off" kernel command line options.
> All but three of the patches were clean cherry-picks. The three that required
> backported were simple backports. These patches have all been applied to
> various linux-stable trees.
> The following changes since commit 53f4f4b0576f627345fb3769fdd6d20b6249dd91:
>   UBUNTU: Ubuntu-4.15.0-47.50 (2019-03-13 04:37:50 +0000)
> are available in the git repository at:
>   https://git.launchpad.net/~tyhicks/ubuntu/+source/linux/+git/bionic speculation

I went ahead and updated this branch with the 4 additional commits that
Juerg identified in the corresponding Cosmic thread. I've boot tested
those additional commits. Here's the updated pull request:

The following changes since commit 53f4f4b0576f627345fb3769fdd6d20b6249dd91:

  UBUNTU: Ubuntu-4.15.0-47.50 (2019-03-13 04:37:50 +0000)

are available in the git repository at:

  https://git.launchpad.net/~tyhicks/ubuntu/+source/linux/+git/bionic speculation

for you to fetch changes up to 5ea0a844e1b95bde97d7a55305358068af5908c5:

  x86, modpost: Replace last remnants of RETPOLINE with CONFIG_RETPOLINE (2019-03-25 18:25:02 +0000)

Andi Kleen (1):
      x86/spectre: Add missing family 6 check to microcode check

Andy Lutomirski (1):
      x86/nmi: Fix NMI uaccess race against CR3 switching

Arnaldo Carvalho de Melo (1):
      tools headers: Synchronize prctl.h ABI header

Jim Mattson (1):
      kvm: svm: Ensure an IBPB on all affected CPUs when freeing a vmcb

Jiri Kosina (3):
      x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation
      x86/speculation: Apply IBPB more strictly to avoid cross-process data leak
      x86/speculation: Propagate information about RSB filling mitigation to sysfs

Konrad Rzeszutek Wilk (3):
      x86/bugs: Add AMD's variant of SSB_NO
      x86/bugs: Add AMD's SPEC_CTRL MSR usage
      x86/bugs: Switch the selection of mitigation from CPU vendor to CPU features

Peter Zijlstra (Intel) (1):
      sched/smt: Make sched_smt_present track topology

Thomas Gleixner (22):
      KVM: x86: SVM: Call x86_spec_ctrl_set_guest/host() with interrupts disabled
      x86/speculation: Rename SSBD update functions
      x86/Kconfig: Select SCHED_SMT if SMP enabled
      sched/smt: Expose sched_smt_present static key
      x86/speculation: Rework SMT state change
      x86/l1tf: Show actual SMT state
      x86/speculation: Reorder the spec_v2 code
      x86/speculation: Mark string arrays const correctly
      x86/speculataion: Mark command line parser data __initdata
      x86/speculation: Unify conditional spectre v2 print functions
      x86/speculation: Add command line control for indirect branch speculation
      x86/process: Consolidate and simplify switch_to_xtra() code
      x86/speculation: Avoid __switch_to_xtra() calls
      x86/speculation: Prepare for conditional IBPB in switch_mm()
      ptrace: Remove unused ptrace_may_access_sched() and MODE_IBRS
      x86/speculation: Split out TIF update
      x86/speculation: Prevent stale SPEC_CTRL msr content
      x86/speculation: Prepare arch_smt_update() for PRCTL mode
      x86/speculation: Add prctl() control for indirect branch speculation
      x86/speculation: Enable prctl mode for spectre_v2_user
      x86/speculation: Add seccomp Spectre v2 user space protection mode
      x86/speculation: Provide IBPB always command line options

Thomas Lendacky (1):
      x86/speculation: Add support for STIBP always-on preferred mode

Tim Chen (7):
      x86/speculation: Update the TIF_SSBD comment
      x86/speculation: Clean up spectre_v2_parse_cmdline()
      x86/speculation: Remove unnecessary ret variable in cpu_show_common()
      x86/speculation: Move STIPB/IBPB string conditionals out of cpu_show_common()
      x86/speculation: Disable STIBP when enhanced IBRS is in use
      x86/speculation: Reorganize speculation control MSRs update
      x86/speculation: Prepare for per task indirect branch speculation control

Tom Lendacky (2):
      x86/bugs: Update when to check for the LS_CFG SSBD mitigation
      x86/bugs: Fix the AMD SSBD usage of the SPEC_CTRL MSR

WANG Chao (1):
      x86, modpost: Replace last remnants of RETPOLINE with CONFIG_RETPOLINE

Waiman Long (1):
      x86/speculation: Change misspelled STIPB to STIBP

Zhenzhong Duan (3):
      x86/speculation: Add RETPOLINE_AMD support to the inline asm CALL_NOSPEC variant
      x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support
      x86/retpoline: Remove minimal retpoline support

 Documentation/admin-guide/kernel-parameters.txt |  56 ++-
 Documentation/userspace-api/spec_ctrl.rst       |   9 +
 arch/x86/Kconfig                                |  12 +-
 arch/x86/Makefile                               |   5 +-
 arch/x86/events/core.c                          |   2 +-
 arch/x86/include/asm/cpufeatures.h              |   3 +
 arch/x86/include/asm/msr-index.h                |   5 +-
 arch/x86/include/asm/nospec-branch.h            |  44 +-
 arch/x86/include/asm/spec-ctrl.h                |  20 +-
 arch/x86/include/asm/switch_to.h                |   3 -
 arch/x86/include/asm/thread_info.h              |  20 +-
 arch/x86/include/asm/tlbflush.h                 |  48 ++-
 arch/x86/kernel/cpu/amd.c                       |   4 +-
 arch/x86/kernel/cpu/bugs.c                      | 528 +++++++++++++++++++-----
 arch/x86/kernel/cpu/common.c                    |   9 +-
 arch/x86/kernel/cpu/intel.c                     |   3 +
 arch/x86/kernel/process.c                       | 101 ++++-
 arch/x86/kernel/process.h                       |  39 ++
 arch/x86/kernel/process_32.c                    |  10 +-
 arch/x86/kernel/process_64.c                    |  10 +-
 arch/x86/kvm/cpuid.c                            |  10 +-
 arch/x86/kvm/svm.c                              |  36 +-
 arch/x86/lib/usercopy.c                         |   5 +
 arch/x86/mm/tlb.c                               | 120 ++++--
 include/linux/compiler-gcc.h                    |   2 +-
 include/linux/module.h                          |   2 +-
 include/linux/ptrace.h                          |   4 +-
 include/linux/sched.h                           |   9 +
 include/linux/sched/smt.h                       |  20 +
 include/uapi/linux/prctl.h                      |   1 +
 kernel/cpu.c                                    |  14 +-
 kernel/sched/core.c                             |  19 +-
 kernel/sched/sched.h                            |   4 +-
 scripts/Makefile.build                          |   2 -
 scripts/mod/modpost.c                           |   2 +-
 tools/include/uapi/linux/prctl.h                |  13 +
 36 files changed, 953 insertions(+), 241 deletions(-)
 create mode 100644 arch/x86/kernel/process.h
 create mode 100644 include/linux/sched/smt.h

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