diff options
| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2019-11-07 05:26:46 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-11-12 21:19:03 +0300 |
| commit | 9b81a067dcfcdc2411338fcc110d90c412c92c76 (patch) | |
| tree | 44df56f4ddf7c8347d8851ecacc2caf8aa5861a1 /arch/x86 | |
| parent | aa6ca7b9a9b72eb61e43f44c978dd8e6d4b2f046 (diff) | |
| download | linux-9b81a067dcfcdc2411338fcc110d90c412c92c76.tar.xz | |
x86/speculation/taa: Fix printing of TAA_MSG_SMT on IBRS_ALL CPUs
commit 012206a822a8b6ac09125bfaa210a95b9eb8f1c1 upstream.
For new IBRS_ALL CPUs, the Enhanced IBRS check at the beginning of
cpu_bugs_smt_update() causes the function to return early, unintentionally
skipping the MDS and TAA logic.
This is not a problem for MDS, because there appears to be no overlap
between IBRS_ALL and MDS-affected CPUs. So the MDS mitigation would be
disabled and nothing would need to be done in this function anyway.
But for TAA, the TAA_MSG_SMT string will never get printed on Cascade
Lake and newer.
The check is superfluous anyway: when 'spectre_v2_enabled' is
SPECTRE_V2_IBRS_ENHANCED, 'spectre_v2_user' is always
SPECTRE_V2_USER_NONE, and so the 'spectre_v2_user' switch statement
handles it appropriately by doing nothing. So just remove the check.
Fixes: 1b42f017415b ("x86/speculation/taa: Add mitigation for TSX Async Abort")
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Tyler Hicks <tyhicks@canonical.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 507aa25176c1..255b79df603c 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -874,10 +874,6 @@ static void update_mds_branch_idle(void) void arch_smt_update(void) { - /* Enhanced IBRS implies STIBP. No update required. */ - if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED) - return; - mutex_lock(&spec_ctrl_mutex); switch (spectre_v2_user) { |