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Date: Sun, 11 Nov 2018 19:49:05 +0000
From: Ben Hutchings <ben@...adent.org.uk>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC: akpm@...ux-foundation.org,
"Tom Lendacky" <thomas.lendacky@....com>,
"Thomas Gleixner" <tglx@...utronix.de>,
"Linus Torvalds" <torvalds@...ux-foundation.org>,
"David Woodhouse" <dwmw@...zon.co.uk>,
"Borislav Petkov" <bpetkov@...e.de>,
"Peter Zijlstra" <peterz@...radead.org>,
"Konrad Rzeszutek Wilk" <konrad.wilk@...cle.com>,
"Ingo Molnar" <mingo@...nel.org>
Subject: [PATCH 3.16 223/366] x86/bugs: Fix the AMD SSBD usage of the
SPEC_CTRL MSR
3.16.61-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Tom Lendacky <thomas.lendacky@....com>
commit 612bc3b3d4be749f73a513a17d9b3ee1330d3487 upstream.
On AMD, the presence of the MSR_SPEC_CTRL feature does not imply that the
SSBD mitigation support should use the SPEC_CTRL MSR. Other features could
have caused the MSR_SPEC_CTRL feature to be set, while a different SSBD
mitigation option is in place.
Update the SSBD support to check for the actual SSBD features that will
use the SPEC_CTRL MSR.
Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
Cc: Borislav Petkov <bpetkov@...e.de>
Cc: David Woodhouse <dwmw@...zon.co.uk>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Fixes: 6ac2f49edb1e ("x86/bugs: Add AMD's SPEC_CTRL MSR usage")
Link: http://lkml.kernel.org/r/20180702213602.29202.33151.stgit@tlendack-t1.amdoffice.net
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
arch/x86/kernel/cpu/bugs.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -219,7 +219,8 @@ x86_virt_spec_ctrl(u64 guest_spec_ctrl,
guestval |= guest_spec_ctrl & x86_spec_ctrl_mask;
/* SSBD controlled in MSR_SPEC_CTRL */
- if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD))
+ if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) ||
+ static_cpu_has(X86_FEATURE_AMD_SSBD))
hostval |= ssbd_tif_to_spec_ctrl(ti->flags);
if (hostval != guestval) {
@@ -573,9 +574,10 @@ static enum ssb_mitigation __init __ssb_
* Intel uses the SPEC CTRL MSR Bit(2) for this, while AMD may
* use a completely different MSR and bit dependent on family.
*/
- if (!static_cpu_has(X86_FEATURE_MSR_SPEC_CTRL))
+ if (!static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) &&
+ !static_cpu_has(X86_FEATURE_AMD_SSBD)) {
x86_amd_ssb_disable();
- else {
+ } else {
x86_spec_ctrl_base |= SPEC_CTRL_SSBD;
x86_spec_ctrl_mask |= SPEC_CTRL_SSBD;
wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base);
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