From: Ben Hutchings <ben@decadent.org.uk>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: akpm@linux-foundation.org, Denis Kirjanov <kda@linux-powerpc.org>,
"Josh Poimboeuf" <jpoimboe@redhat.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Tyler Hicks" <tyhicks@canonical.com>,
"Borislav Petkov" <bp@suse.de>
Subject: [PATCH 3.16 12/25] x86/speculation/taa: Fix printing of TAA_MSG_SMT on IBRS_ALL CPUs
Date: Tue, 12 Nov 2019 23:48:09 +0000 [thread overview]
Message-ID: <lsq.1573602477.999910664@decadent.org.uk> (raw)
In-Reply-To: <lsq.1573602477.548403712@decadent.org.uk>
3.16.77-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Josh Poimboeuf <jpoimboe@redhat.com>
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: Ben Hutchings <ben@decadent.org.uk>
---
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
@@ -919,10 +919,6 @@ 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) {
next prev parent reply other threads:[~2019-11-12 23:51 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-12 23:47 [PATCH 3.16 00/25] 3.16.77-rc1 review Ben Hutchings
2019-11-12 23:47 ` [PATCH 3.16 01/25] KVM: Introduce kvm_get_arch_capabilities() Ben Hutchings
2019-11-12 23:47 ` [PATCH 3.16 02/25] KVM: x86: use Intel speculation bugs and features as derived in generic x86 code Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 03/25] x86/msr: Add the IA32_TSX_CTRL MSR Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 04/25] x86/cpu: Add a helper function x86_read_arch_cap_msr() Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 05/25] x86/cpu: Add a "tsx=" cmdline option with TSX disabled by default Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 06/25] x86/speculation/taa: Add mitigation for TSX Async Abort Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 07/25] x86/speculation/taa: Add sysfs reporting " Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 08/25] kvm/x86: Export MDS_NO=0 to guests when TSX is enabled Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 09/25] x86/tsx: Add "auto" option to the tsx= cmdline parameter Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 10/25] x86/speculation/taa: Add documentation for TSX Async Abort Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 11/25] x86/tsx: Add config options to set tsx=on|off|auto Ben Hutchings
2019-11-12 23:48 ` Ben Hutchings [this message]
2019-11-12 23:48 ` [PATCH 3.16 13/25] x86/bugs: Add ITLB_MULTIHIT bug infrastructure Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 14/25] drm/i915/gen8+: Add RC6 CTX corruption WA Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 15/25] net: netem: fix error path for corrupted GSO frames Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 16/25] ath6kl: fix a NULL-ptr-deref bug in ath6kl_usb_alloc_urb_from_pipe() Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 17/25] media: usb:zr364xx:Fix KASAN:null-ptr-deref Read in zr364xx_vidioc_querycap Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 18/25] media: technisat-usb2: break out of loop at end of buffer Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 19/25] ax25: enforce CAP_NET_RAW for raw sockets Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 20/25] ieee802154: " Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 21/25] appletalk: " Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 22/25] mISDN: " Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 23/25] nfc: " Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 24/25] cfg80211: wext: avoid copying malformed SSIDs Ben Hutchings
2019-11-12 23:48 ` [PATCH 3.16 25/25] rtlwifi: Fix potential overflow on P2P code Ben Hutchings
2019-11-13 18:13 ` [PATCH 3.16 00/25] 3.16.77-rc1 review Guenter Roeck
2019-11-13 18:31 ` Ben Hutchings
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