This backport introduces IBRS support to 5.4.y in order to mitigate Retbleed on Intel parts. Though some very small pieces for AMD have been picked up as well, "UNRET" mitigations are not backported, nor IBPB. It is expected, though, that the backport will report AMD systems as vulnerable or not affected, depending on the parts and the BTC_NO bit.
One note here is that the PBRSB mitigation was backported previously to the 5.4 series, and this would have made things a little bit more complicated. So, I reverted it and applied it later on.
This has been boot-tested and smoke-tested on a bunch of AMD and Intel systems.
Alexandre Chartre (2): x86/bugs: Report AMD retbleed vulnerability x86/bugs: Add AMD retbleed= boot parameter
Andrew Cooper (1): x86/cpu/amd: Enumerate BTC_NO
Daniel Sneddon (1): x86/speculation: Add RSB VM Exit protections
Josh Poimboeuf (9): x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=n x86/speculation: Fix firmware entry SPEC_CTRL handling x86/speculation: Fix SPEC_CTRL write on SMT state change x86/speculation: Use cached host SPEC_CTRL value for guest entry/exit x86/speculation: Remove x86_spec_ctrl_mask KVM: VMX: Flatten __vmx_vcpu_run() KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS KVM: VMX: Fix IBRS handling after vmexit x86/speculation: Fill RSB on vmexit for IBRS
Mark Gross (1): x86/cpu: Add a steppings field to struct x86_cpu_id
Nathan Chancellor (1): x86/speculation: Use DECLARE_PER_CPU for x86_spec_ctrl_current
Pawan Gupta (4): x86/speculation: Add spectre_v2=ibrs option to support Kernel IBRS x86/bugs: Add Cannon lake to RETBleed affected CPU list x86/speculation: Disable RRSBA behavior x86/bugs: Warn when "ibrs" mitigation is selected on Enhanced IBRS parts
Peter Zijlstra (11): x86/kvm/vmx: Make noinstr clean x86/cpufeatures: Move RETPOLINE flags to word 11 x86/bugs: Keep a per-CPU IA32_SPEC_CTRL value x86/entry: Remove skip_r11rcx x86/entry: Add kernel IBRS implementation x86/bugs: Optimize SPEC_CTRL MSR writes x86/bugs: Split spectre_v2_select_mitigation() and spectre_v2_user_select_mitigation() x86/bugs: Report Intel retbleed vulnerability intel_idle: Disable IBRS during long idle x86/speculation: Change FILL_RETURN_BUFFER to work with objtool x86/common: Stamp out the stepping madness
Thadeu Lima de Souza Cascardo (3): Revert "x86/speculation: Add RSB VM Exit protections" Revert "x86/cpu: Add a steppings field to struct x86_cpu_id" KVM: VMX: Convert launched argument to flags
Thomas Gleixner (2): x86/devicetable: Move x86 specific macro out of generic code x86/cpu: Add consistent CPU match macros
Uros Bizjak (2): KVM/VMX: Use TEST %REG,%REG instead of CMP $0,%REG in vmenter.S KVM/nVMX: Use __vmx_vcpu_run in nested_vmx_check_vmentry_hw
.../admin-guide/kernel-parameters.txt | 13 + arch/x86/entry/calling.h | 68 +++- arch/x86/entry/entry_32.S | 2 - arch/x86/entry/entry_64.S | 34 +- arch/x86/entry/entry_64_compat.S | 11 +- arch/x86/include/asm/cpu_device_id.h | 132 ++++++- arch/x86/include/asm/cpufeatures.h | 13 +- arch/x86/include/asm/intel-family.h | 6 + arch/x86/include/asm/msr-index.h | 10 + arch/x86/include/asm/nospec-branch.h | 54 +-- arch/x86/kernel/cpu/amd.c | 21 +- arch/x86/kernel/cpu/bugs.c | 365 ++++++++++++++---- arch/x86/kernel/cpu/common.c | 61 +-- arch/x86/kernel/cpu/match.c | 13 +- arch/x86/kernel/cpu/scattered.c | 1 + arch/x86/kernel/process.c | 2 +- arch/x86/kvm/svm.c | 1 + arch/x86/kvm/vmx/nested.c | 32 +- arch/x86/kvm/vmx/run_flags.h | 8 + arch/x86/kvm/vmx/vmenter.S | 161 ++++---- arch/x86/kvm/vmx/vmx.c | 72 ++-- arch/x86/kvm/vmx/vmx.h | 5 + arch/x86/kvm/x86.c | 4 +- drivers/base/cpu.c | 8 + drivers/cpufreq/acpi-cpufreq.c | 1 + drivers/cpufreq/amd_freq_sensitivity.c | 1 + drivers/idle/intel_idle.c | 43 ++- include/linux/cpu.h | 2 + include/linux/kvm_host.h | 2 +- include/linux/mod_devicetable.h | 4 +- tools/arch/x86/include/asm/cpufeatures.h | 2 +- 31 files changed, 840 insertions(+), 312 deletions(-) create mode 100644 arch/x86/kvm/vmx/run_flags.h