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Signed-off-by: David Kaplan --- arch/x86/kernel/cpu/bugs.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 9d5c6a3e50e1..0430635bb17d 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -2477,6 +2477,24 @@ static void __init spectre_v2_apply_mitigation(void) } } =20 +#ifdef CONFIG_DYNAMIC_MITIGATIONS +static void spectre_v2_reset_mitigation(void) +{ + x86_spec_ctrl_base &=3D ~SPEC_CTRL_IBRS; + x86_spec_ctrl_base &=3D ~SPEC_CTRL_RRSBA_DIS_S; + rrsba_disabled =3D false; + setup_clear_cpu_cap(X86_FEATURE_KERNEL_IBRS); + setup_clear_cpu_cap(X86_FEATURE_RETPOLINE_LFENCE); + setup_clear_cpu_cap(X86_FEATURE_RETPOLINE); + setup_clear_cpu_cap(X86_FEATURE_RSB_CTXSW); + setup_clear_cpu_cap(X86_FEATURE_USE_IBPB_FW); + spectre_v2_enabled =3D SPECTRE_V2_NONE; + nospectre_v2 =3D false; + spectre_v2_cmd =3D IS_ENABLED(CONFIG_MITIGATION_SPECTRE_V2) ? + SPECTRE_V2_CMD_AUTO : SPECTRE_V2_CMD_NONE; +} +#endif + static void update_stibp_msr(void * __unused) { u64 val =3D spec_ctrl_current() | (x86_spec_ctrl_base & SPEC_CTRL_STIBP); @@ -3810,5 +3828,6 @@ void __warn_thunk(void) void arch_cpu_reset_mitigations(void) { spectre_v1_reset_mitigation(); + spectre_v2_reset_mitigation(); } #endif --=20 2.34.1