Messages in this thread Patch in this message | | | Date | Tue, 15 Aug 2023 11:57:24 +0200 | From | Borislav Petkov <> | Subject | [PATCH] x86/srso: Correct the mitigation status when SMT is disabled |
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On Mon, Aug 14, 2023 at 11:17:27PM +0200, Borislav Petkov wrote: > Lemme see how ugly it becomes tomorrow.
Not too bad, considering bugs.c's ugliness.
From: "Borislav Petkov (AMD)" <bp@alien8.de> Date: Tue, 15 Aug 2023 11:53:13 +0200 Subject: [PATCH] x86/srso: Correct the mitigation status when SMT is disabled
Specify how is SRSO mitigated when SMT is disabled. Also, correct the SMT check for that.
Fixes: e9fbc47b818b ("x86/srso: Disable the mitigation on unaffected configurations") Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> --- arch/x86/kernel/cpu/bugs.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 6c04aef4b63b..dc8f874fdd63 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -2417,8 +2417,7 @@ static void __init srso_select_mitigation(void) * Zen1/2 with SMT off aren't vulnerable after the right * IBPB microcode has been applied. */ - if ((boot_cpu_data.x86 < 0x19) && - (!cpu_smt_possible() || (cpu_smt_control == CPU_SMT_DISABLED))) { + if (boot_cpu_data.x86 < 0x19 && !cpu_smt_possible()) { setup_force_cpu_cap(X86_FEATURE_SRSO_NO); return; } @@ -2698,8 +2697,12 @@ static ssize_t retbleed_show_state(char *buf) static ssize_t srso_show_state(char *buf) { - if (boot_cpu_has(X86_FEATURE_SRSO_NO)) - return sysfs_emit(buf, "Not affected\n"); + if (boot_cpu_has(X86_FEATURE_SRSO_NO)) { + if (sched_smt_active()) + return sysfs_emit(buf, "Not affected\n"); + else + return sysfs_emit(buf, "Mitigation: SMT disabled\n"); + } return sysfs_emit(buf, "%s%s\n", srso_strings[srso_mitigation], -- 2.42.0.rc0.25.ga82fb66fed25 -- Regards/Gruss, Boris.
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