ACK/Cmnt: [SRU][Bionic][PULL+follow-up] Update speculation side-channel mitigations
Stefan Bader
stefan.bader at canonical.com
Wed Mar 27 15:02:50 UTC 2019
On 25.03.19 05:58, 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
>
> for you to fetch changes up to c50e39ffc134b9db8b3f8ee97bf6935f5e11d22a:
>
> x86/speculation: Provide IBPB always command line options (2019-03-15 18:33:39 +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
>
> 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
>
> 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
>
> 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 | 2 +
> arch/x86/include/asm/msr-index.h | 5 +-
> arch/x86/include/asm/nospec-branch.h | 43 +-
> 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 | 510 +++++++++++++++++++-----
> 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 | 16 +-
> arch/x86/lib/usercopy.c | 5 +
> arch/x86/mm/tlb.c | 120 ++++--
> 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 -
> tools/include/uapi/linux/prctl.h | 13 +
> 33 files changed, 916 insertions(+), 232 deletions(-)
> create mode 100644 arch/x86/kernel/process.h
> create mode 100644 include/linux/sched/smt.h
>
>
More or less with same comments as for the Cosmic set. With additionally
wondering whether the 2 follow-ups might also be needed in Cosmic. I think the
follow-ups from that submission were added to this Bionic one.
Acked-by: Stefan Bader <stefan.bader at canonical.com>
[including follow-up patches]
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