45 lines
1.6 KiB
Diff
45 lines
1.6 KiB
Diff
From: Josh Poimboeuf <jpoimboe@redhat.com>
|
|
Date: Wed, 6 Nov 2019 20:26:46 -0600
|
|
Subject: 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>
|
|
---
|
|
arch/x86/kernel/cpu/bugs.c | 4 ----
|
|
1 file changed, 4 deletions(-)
|
|
|
|
--- 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) {
|