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Signed-off-by: David Kaplan --- arch/x86/kernel/cpu/bugs.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 0430635bb17d..1f56ccb5f641 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -1542,6 +1542,20 @@ static void __init retbleed_apply_mitigation(void) cpu_smt_disable(false); } =20 +#ifdef CONFIG_DYNAMIC_MITIGATIONS +static void retbleed_reset_mitigation(void) +{ + setup_clear_cpu_cap(X86_FEATURE_RETHUNK); + setup_clear_cpu_cap(X86_FEATURE_UNRET); + setup_clear_cpu_cap(X86_FEATURE_ENTRY_IBPB); + setup_clear_cpu_cap(X86_FEATURE_IBPB_ON_VMEXIT); + setup_clear_cpu_cap(X86_FEATURE_CALL_DEPTH); + x86_return_thunk =3D __x86_return_thunk; + retbleed_mitigation =3D IS_ENABLED(CONFIG_MITIGATION_RETBLEED) ? + RETBLEED_MITIGATION_AUTO : RETBLEED_MITIGATION_NONE; +} +#endif + #undef pr_fmt #define pr_fmt(fmt) "ITS: " fmt =20 @@ -3829,5 +3843,6 @@ void arch_cpu_reset_mitigations(void) { spectre_v1_reset_mitigation(); spectre_v2_reset_mitigation(); + retbleed_reset_mitigation(); } #endif --=20 2.34.1