diff options
| author | David Kaplan <david.kaplan@amd.com> | 2025-07-07 13:33:00 -0500 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2025-07-11 17:56:40 +0200 |
| commit | e3a88d4c068242c00a1d6ddfd3c711fc22983f75 (patch) | |
| tree | 06c0c8264d2fa57073f2100662207ffb834933b3 /arch/x86/kernel/cpu/bugs.c | |
| parent | 2d31d2874663cde2cab8c18bfb52ed8be6dfa958 (diff) | |
x86/bugs: Add attack vector controls for MDS
Use attack vector controls to determine if MDS mitigation is required.
The global mitigations=off command now simply disables all attack vectors
so explicit checking of mitigations=off is no longer needed.
If cross-thread attack mitigations are required, disable SMT.
Signed-off-by: David Kaplan <david.kaplan@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250707183316.1349127-6-david.kaplan@amd.com
Diffstat (limited to 'arch/x86/kernel/cpu/bugs.c')
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index b083e7eabc56..31e0cf87d71e 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -441,13 +441,17 @@ static bool verw_clear_cpu_buf_mitigation_selected __ro_after_init; static void __init mds_select_mitigation(void) { - if (!boot_cpu_has_bug(X86_BUG_MDS) || cpu_mitigations_off()) { + if (!boot_cpu_has_bug(X86_BUG_MDS)) { mds_mitigation = MDS_MITIGATION_OFF; return; } - if (mds_mitigation == MDS_MITIGATION_AUTO) - mds_mitigation = MDS_MITIGATION_FULL; + if (mds_mitigation == MDS_MITIGATION_AUTO) { + if (should_mitigate_vuln(X86_BUG_MDS)) + mds_mitigation = MDS_MITIGATION_FULL; + else + mds_mitigation = MDS_MITIGATION_OFF; + } if (mds_mitigation == MDS_MITIGATION_OFF) return; @@ -457,7 +461,7 @@ static void __init mds_select_mitigation(void) static void __init mds_update_mitigation(void) { - if (!boot_cpu_has_bug(X86_BUG_MDS) || cpu_mitigations_off()) + if (!boot_cpu_has_bug(X86_BUG_MDS)) return; /* If TAA, MMIO, or RFDS are being mitigated, MDS gets mitigated too. */ @@ -478,7 +482,7 @@ static void __init mds_apply_mitigation(void) mds_mitigation == MDS_MITIGATION_VMWERV) { setup_force_cpu_cap(X86_FEATURE_CLEAR_CPU_BUF); if (!boot_cpu_has(X86_BUG_MSBDS_ONLY) && - (mds_nosmt || cpu_mitigations_auto_nosmt())) + (mds_nosmt || smt_mitigations == SMT_MITIGATIONS_ON)) cpu_smt_disable(false); } } |