This is a note to let you know that I've just added the patch titled
x86/speculation/mmio: Reuse SRBDS mitigation for SBDS
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-speculation-mmio-reuse-srbds-mitigation-for-sbds.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Tue Jun 14 07:10:28 PM CEST 2022
From: Pawan Gupta <pawan.kumar.gupta@xxxxxxxxxxxxxxx>
Date: Thu, 19 May 2022 20:34:14 -0700
Subject: x86/speculation/mmio: Reuse SRBDS mitigation for SBDS
From: Pawan Gupta <pawan.kumar.gupta@xxxxxxxxxxxxxxx>
commit a992b8a4682f119ae035a01b40d4d0665c4a2875 upstream
The Shared Buffers Data Sampling (SBDS) variant of Processor MMIO Stale
Data vulnerabilities may expose RDRAND, RDSEED and SGX EGETKEY data.
Mitigation for this is added by a microcode update.
As some of the implications of SBDS are similar to SRBDS, SRBDS mitigation
infrastructure can be leveraged by SBDS. Set X86_BUG_SRBDS and use SRBDS
mitigation.
Mitigation is enabled by default; use srbds=off to opt-out. Mitigation
status can be checked from below file:
/sys/devices/system/cpu/vulnerabilities/srbds
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@xxxxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
[cascardo: adjust for processor model names]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/common.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -964,6 +964,8 @@ static const __initconst struct x86_cpu_
#define SRBDS BIT(0)
/* CPU is affected by X86_BUG_MMIO_STALE_DATA */
#define MMIO BIT(1)
+/* CPU is affected by Shared Buffers Data Sampling (SBDS), a variant of X86_BUG_MMIO_STALE_DATA */
+#define MMIO_SBDS BIT(2)
static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = {
VULNBL_INTEL_STEPPINGS(IVYBRIDGE, X86_STEPPING_ANY, SRBDS),
@@ -985,16 +987,17 @@ static const struct x86_cpu_id cpu_vuln_
VULNBL_INTEL_STEPPINGS(KABYLAKE_MOBILE, X86_STEPPINGS(0x0, 0x8), SRBDS),
VULNBL_INTEL_STEPPINGS(KABYLAKE_DESKTOP,X86_STEPPINGS(0x9, 0xD), SRBDS | MMIO),
VULNBL_INTEL_STEPPINGS(KABYLAKE_DESKTOP,X86_STEPPINGS(0x0, 0x8), SRBDS),
- VULNBL_INTEL_STEPPINGS(ICELAKE_MOBILE, X86_STEPPINGS(0x5, 0x5), MMIO),
+ VULNBL_INTEL_STEPPINGS(ICELAKE_MOBILE, X86_STEPPINGS(0x5, 0x5), MMIO | MMIO_SBDS),
VULNBL_INTEL_STEPPINGS(ICELAKE_XEON_D, X86_STEPPINGS(0x1, 0x1), MMIO),
VULNBL_INTEL_STEPPINGS(ICELAKE_X, X86_STEPPINGS(0x4, 0x6), MMIO),
- VULNBL_INTEL_STEPPINGS(COMETLAKE, BIT(2) | BIT(3) | BIT(5), MMIO),
- VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x0, 0x1), MMIO),
- VULNBL_INTEL_STEPPINGS(LAKEFIELD, X86_STEPPINGS(0x1, 0x1), MMIO),
+ VULNBL_INTEL_STEPPINGS(COMETLAKE, BIT(2) | BIT(3) | BIT(5), MMIO | MMIO_SBDS),
+ VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS),
+ VULNBL_INTEL_STEPPINGS(COMETLAKE_L, X86_STEPPINGS(0x0, 0x0), MMIO),
+ VULNBL_INTEL_STEPPINGS(LAKEFIELD, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS),
VULNBL_INTEL_STEPPINGS(ROCKETLAKE, X86_STEPPINGS(0x1, 0x1), MMIO),
- VULNBL_INTEL_STEPPINGS(ATOM_TREMONT, X86_STEPPINGS(0x1, 0x1), MMIO),
+ VULNBL_INTEL_STEPPINGS(ATOM_TREMONT, X86_STEPPINGS(0x1, 0x1), MMIO | MMIO_SBDS),
VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_X, X86_STEPPING_ANY, MMIO),
- VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_L, X86_STEPPINGS(0x0, 0x0), MMIO),
+ VULNBL_INTEL_STEPPINGS(ATOM_TREMONT_L, X86_STEPPINGS(0x0, 0x0), MMIO | MMIO_SBDS),
{}
};
@@ -1073,10 +1076,14 @@ static void __init cpu_set_bug_bits(stru
/*
* SRBDS affects CPUs which support RDRAND or RDSEED and are listed
* in the vulnerability blacklist.
+ *
+ * Some of the implications and mitigation of Shared Buffers Data
+ * Sampling (SBDS) are similar to SRBDS. Give SBDS same treatment as
+ * SRBDS.
*/
if ((cpu_has(c, X86_FEATURE_RDRAND) ||
cpu_has(c, X86_FEATURE_RDSEED)) &&
- cpu_matches(cpu_vuln_blacklist, SRBDS))
+ cpu_matches(cpu_vuln_blacklist, SRBDS | MMIO_SBDS))
setup_force_cpu_bug(X86_BUG_SRBDS);
/*
Patches currently in stable-queue which might be from pawan.kumar.gupta@xxxxxxxxxxxxxxx are
queue-4.9/x86-speculation-add-a-common-function-for-md_clear-mitigation-update.patch
queue-4.9/x86-speculation-mmio-reuse-srbds-mitigation-for-sbds.patch
queue-4.9/x86-speculation-mmio-add-sysfs-reporting-for-processor-mmio-stale-data.patch
queue-4.9/x86-speculation-srbds-update-srbds-mitigation-selection.patch
queue-4.9/x86-speculation-mmio-enable-cpu-fill-buffer-clearing-on-idle.patch
queue-4.9/x86-bugs-group-mds-taa-processor-mmio-stale-data-mitigations.patch
queue-4.9/x86-speculation-mmio-enumerate-processor-mmio-stale-data-bug.patch
queue-4.9/documentation-add-documentation-for-processor-mmio-stale-data.patch
queue-4.9/kvm-x86-speculation-disable-fill-buffer-clear-within-guests.patch
queue-4.9/x86-speculation-mmio-add-mitigation-for-processor-mmio-stale-data.patch
