From cd5a2aa89e847bdda7b62029d94e95488d73f6b2 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Fri, 15 Nov 2019 11:14:45 -0500 Subject: [PATCH] x86/speculation: Fix redundant MDS mitigation message Since MDS and TAA mitigations are inter-related for processors that are affected by both vulnerabilities, the followiing confusing messages can be printed in the kernel log: MDS: Vulnerable MDS: Mitigation: Clear CPU buffers To avoid the first incorrect message, defer the printing of MDS mitigation after the TAA mitigation selection has been done. However, that has the side effect of printing TAA mitigation first before MDS mitigation. [ bp: Check box is affected/mitigations are disabled first before printing and massage. ] Suggested-by: Pawan Gupta Signed-off-by: Waiman Long Signed-off-by: Borislav Petkov Cc: Greg Kroah-Hartman Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Josh Poimboeuf Cc: Mark Gross Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tim Chen Cc: Tony Luck Cc: Tyler Hicks Cc: x86-ml Link: https://lkml.kernel.org/r/20191115161445.30809-3-longman@redhat.com --- arch/x86/kernel/cpu/bugs.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index cb513eaa0df1..8bf64899f56a 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -39,6 +39,7 @@ static void __init spectre_v2_select_mitigation(void); static void __init ssb_select_mitigation(void); static void __init l1tf_select_mitigation(void); static void __init mds_select_mitigation(void); +static void __init mds_print_mitigation(void); static void __init taa_select_mitigation(void); /* The base value of the SPEC_CTRL MSR that always has to be preserved. */ @@ -108,6 +109,12 @@ void __init check_bugs(void) mds_select_mitigation(); taa_select_mitigation(); + /* + * As MDS and TAA mitigations are inter-related, print MDS + * mitigation until after TAA mitigation selection is done. + */ + mds_print_mitigation(); + arch_smt_update(); #ifdef CONFIG_X86_32 @@ -245,6 +252,12 @@ static void __init mds_select_mitigation(void) (mds_nosmt || cpu_mitigations_auto_nosmt())) cpu_smt_disable(false); } +} + +static void __init mds_print_mitigation(void) +{ + if (!boot_cpu_has_bug(X86_BUG_MDS) || cpu_mitigations_off()) + return; pr_info("%s\n", mds_strings[mds_mitigation]); } -- 2.11.0