diff options
| author | Josh Poimboeuf <jpoimboe@kernel.org> | 2025-04-08 14:47:33 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-04-09 12:41:55 +0200 |
| commit | 18bae0dfec15b24ec14ca17dc18603372f5f254f (patch) | |
| tree | 32855ad9816301f74424af456152276859eb2f9e /arch | |
| parent | b1b19cfcf4656c75088dc06b7499f493e0dec3e5 (diff) | |
x86/bugs: Don't fill RSB on VMEXIT with eIBRS+retpoline
eIBRS protects against guest->host RSB underflow/poisoning attacks.
Adding retpoline to the mix doesn't change that. Retpoline has a
balanced CALL/RET anyway.
So the current full RSB filling on VMEXIT with eIBRS+retpoline is
overkill. Disable it or do the VMEXIT_LITE mitigation if needed.
Suggested-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Reviewed-by: Amit Shah <amit.shah@amd.com>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Link: https://lore.kernel.org/r/84a1226e5c9e2698eae1b5ade861f1b8bf3677dc.1744148254.git.jpoimboe@kernel.org
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 99265098d045..a10b37bb747e 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -1617,20 +1617,20 @@ static void __init spectre_v2_determine_rsb_fill_type_at_vmexit(enum spectre_v2_ case SPECTRE_V2_NONE: return; - case SPECTRE_V2_EIBRS_LFENCE: case SPECTRE_V2_EIBRS: + case SPECTRE_V2_EIBRS_LFENCE: + case SPECTRE_V2_EIBRS_RETPOLINE: if (boot_cpu_has_bug(X86_BUG_EIBRS_PBRSB)) { - setup_force_cpu_cap(X86_FEATURE_RSB_VMEXIT_LITE); pr_info("Spectre v2 / PBRSB-eIBRS: Retire a single CALL on VMEXIT\n"); + setup_force_cpu_cap(X86_FEATURE_RSB_VMEXIT_LITE); } return; - case SPECTRE_V2_EIBRS_RETPOLINE: case SPECTRE_V2_RETPOLINE: case SPECTRE_V2_LFENCE: case SPECTRE_V2_IBRS: - setup_force_cpu_cap(X86_FEATURE_RSB_VMEXIT); pr_info("Spectre v2 / SpectreRSB : Filling RSB on VMEXIT\n"); + setup_force_cpu_cap(X86_FEATURE_RSB_VMEXIT); return; } |