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authorJosh Poimboeuf <jpoimboe@kernel.org>2024-04-12 21:10:33 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2024-04-27 18:11:37 +0300
commit5facc0428bd2cb2fd3bb7f46d8b862b941a364b3 (patch)
treeaf340c940501bf3b235a412528c7aad470d4654d /arch
parentc0dcd5c072e2a3fff886f673e6a5d9bf8090c4cc (diff)
downloadlinux-5facc0428bd2cb2fd3bb7f46d8b862b941a364b3.tar.xz
x86/bugs: Fix BHI retpoline check
[ Upstream commit 69129794d94c544810e68b2b4eaa7e44063f9bf2 ] Confusingly, X86_FEATURE_RETPOLINE doesn't mean retpolines are enabled, as it also includes the original "AMD retpoline" which isn't a retpoline at all. Also replace cpu_feature_enabled() with boot_cpu_has() because this is before alternatives are patched and cpu_feature_enabled()'s fallback path is slower than plain old boot_cpu_has(). Fixes: ec9404e40e8f ("x86/bhi: Add BHI mitigation knob") 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> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/ad3807424a3953f0323c011a643405619f2a4927.1712944776.git.jpoimboe@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/bugs.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 5ff69b1d39b2..c2dc9b7426ac 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -1651,7 +1651,8 @@ static void __init bhi_select_mitigation(void)
return;
/* Retpoline mitigates against BHI unless the CPU has RRSBA behavior */
- if (cpu_feature_enabled(X86_FEATURE_RETPOLINE)) {
+ if (boot_cpu_has(X86_FEATURE_RETPOLINE) &&
+ !boot_cpu_has(X86_FEATURE_RETPOLINE_LFENCE)) {
spec_ctrl_disable_kernel_rrsba();
if (rrsba_disabled)
return;
@@ -2803,11 +2804,13 @@ static const char *spectre_bhi_state(void)
{
if (!boot_cpu_has_bug(X86_BUG_BHI))
return "; BHI: Not affected";
- else if (boot_cpu_has(X86_FEATURE_CLEAR_BHB_HW))
+ else if (boot_cpu_has(X86_FEATURE_CLEAR_BHB_HW))
return "; BHI: BHI_DIS_S";
- else if (boot_cpu_has(X86_FEATURE_CLEAR_BHB_LOOP))
+ else if (boot_cpu_has(X86_FEATURE_CLEAR_BHB_LOOP))
return "; BHI: SW loop, KVM: SW loop";
- else if (boot_cpu_has(X86_FEATURE_RETPOLINE) && rrsba_disabled)
+ else if (boot_cpu_has(X86_FEATURE_RETPOLINE) &&
+ !boot_cpu_has(X86_FEATURE_RETPOLINE_LFENCE) &&
+ rrsba_disabled)
return "; BHI: Retpoline";
else if (boot_cpu_has(X86_FEATURE_CLEAR_BHB_LOOP_ON_VMEXIT))
return "; BHI: Vulnerable, KVM: SW loop";