diff options
| author | David Kaplan <david.kaplan@amd.com> | 2025-06-25 10:58:03 -0500 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-06-26 10:56:39 +0200 |
| commit | 1fd5eb02867ac7db9144bd44c8edfad0189c8e57 (patch) | |
| tree | 68efa5768c00e158118273022ea43888602a2303 /arch/x86/kernel/cpu/bugs.c | |
| parent | ab9f2388e0b99cd164ddbd74a6133d3070e2788d (diff) | |
x86/bugs: Add SRSO_MITIGATION_NOSMT
AMD Zen1 and Zen2 CPUs with SMT disabled are not vulnerable to SRSO.
Instead of overloading the X86_FEATURE_SRSO_NO bit to indicate this,
define a separate mitigation to make the code cleaner.
Signed-off-by: David Kaplan <david.kaplan@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: H . Peter Anvin <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250625155805.600376-2-david.kaplan@amd.com
Diffstat (limited to 'arch/x86/kernel/cpu/bugs.c')
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index bdef2c9aa1b8..6c991afb7b78 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -2851,6 +2851,7 @@ enum srso_mitigation { SRSO_MITIGATION_UCODE_NEEDED, SRSO_MITIGATION_SAFE_RET_UCODE_NEEDED, SRSO_MITIGATION_MICROCODE, + SRSO_MITIGATION_NOSMT, SRSO_MITIGATION_SAFE_RET, SRSO_MITIGATION_IBPB, SRSO_MITIGATION_IBPB_ON_VMEXIT, @@ -2862,6 +2863,7 @@ static const char * const srso_strings[] = { [SRSO_MITIGATION_UCODE_NEEDED] = "Vulnerable: No microcode", [SRSO_MITIGATION_SAFE_RET_UCODE_NEEDED] = "Vulnerable: Safe RET, no microcode", [SRSO_MITIGATION_MICROCODE] = "Vulnerable: Microcode, no safe RET", + [SRSO_MITIGATION_NOSMT] = "Mitigation: SMT disabled", [SRSO_MITIGATION_SAFE_RET] = "Mitigation: Safe RET", [SRSO_MITIGATION_IBPB] = "Mitigation: IBPB", [SRSO_MITIGATION_IBPB_ON_VMEXIT] = "Mitigation: IBPB on VMEXIT only", @@ -2914,8 +2916,7 @@ static void __init srso_select_mitigation(void) * IBPB microcode has been applied. */ if (boot_cpu_data.x86 < 0x19 && !cpu_smt_possible()) { - setup_force_cpu_cap(X86_FEATURE_SRSO_NO); - srso_mitigation = SRSO_MITIGATION_NONE; + srso_mitigation = SRSO_MITIGATION_NOSMT; return; } } else { @@ -2968,8 +2969,7 @@ static void __init srso_update_mitigation(void) srso_mitigation = SRSO_MITIGATION_IBPB; if (boot_cpu_has_bug(X86_BUG_SRSO) && - !cpu_mitigations_off() && - !boot_cpu_has(X86_FEATURE_SRSO_NO)) + !cpu_mitigations_off()) pr_info("%s\n", srso_strings[srso_mitigation]); } @@ -3265,9 +3265,6 @@ 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, "Mitigation: SMT disabled\n"); - return sysfs_emit(buf, "%s\n", srso_strings[srso_mitigation]); } |