From: Yian Chen <yian.chen@intel.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Ravi Shankar <ravi.v.shankar@intel.com>,
Tony Luck <tony.luck@intel.com>,
Sohil Mehta <sohil.mehta@intel.com>,
Paul Lai <paul.c.lai@intel.com>, Yian Chen <yian.chen@intel.com>
Subject: [PATCH 2/7] x86: Add CONFIG option X86_LASS
Date: Mon, 9 Jan 2023 21:51:59 -0800 [thread overview]
Message-ID: <20230110055204.3227669-3-yian.chen@intel.com> (raw)
In-Reply-To: <20230110055204.3227669-1-yian.chen@intel.com>
LASS is an Intel x86-64 only feature. Add CONFIG
option X86_LASS and flag DISABLE_LASS to choose
opt-in/out the feature from kernel binary.
CONFIG_X86_LASS is enabled by default because it
is a security feature which should have little
to no overhead or side effects. If any issues are
found with specific use cases, the CONFIG option
makes it easy to disable.
Signed-off-by: Yian Chen <yian.chen@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
---
arch/x86/Kconfig | 10 ++++++++++
arch/x86/include/asm/disabled-features.h | 8 +++++++-
tools/arch/x86/include/asm/disabled-features.h | 8 +++++++-
3 files changed, 24 insertions(+), 2 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 3604074a878b..38b1497afd75 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1826,6 +1826,16 @@ config ARCH_USES_PG_UNCACHED
def_bool y
depends on X86_PAT
+config X86_LASS
+ def_bool y
+ prompt "Linear Address Space Separation"
+ depends on X86_64 && CPU_SUP_INTEL
+ help
+ Linear Address Space Separation (LASS) is a processor
+ feature that mitigates address space layout probes.
+
+ if unsure, say Y.
+
config X86_UMIP
def_bool y
prompt "User Mode Instruction Prevention" if EXPERT
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index c44b56f7ffba..0cad37d59e0f 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -16,6 +16,12 @@
# define DISABLE_UMIP (1<<(X86_FEATURE_UMIP & 31))
#endif
+#ifdef CONFIG_X86_LASS
+# define DISABLE_LASS 0
+#else
+# define DISABLE_LASS (1<<(X86_FEATURE_LASS & 31))
+#endif
+
#ifdef CONFIG_X86_64
# define DISABLE_VME (1<<(X86_FEATURE_VME & 31))
# define DISABLE_K6_MTRR (1<<(X86_FEATURE_K6_MTRR & 31))
@@ -115,7 +121,7 @@
#define DISABLED_MASK10 0
#define DISABLED_MASK11 (DISABLE_RETPOLINE|DISABLE_RETHUNK|DISABLE_UNRET| \
DISABLE_CALL_DEPTH_TRACKING)
-#define DISABLED_MASK12 0
+#define DISABLED_MASK12 (DISABLE_LASS)
#define DISABLED_MASK13 0
#define DISABLED_MASK14 0
#define DISABLED_MASK15 0
diff --git a/tools/arch/x86/include/asm/disabled-features.h b/tools/arch/x86/include/asm/disabled-features.h
index c44b56f7ffba..0cad37d59e0f 100644
--- a/tools/arch/x86/include/asm/disabled-features.h
+++ b/tools/arch/x86/include/asm/disabled-features.h
@@ -16,6 +16,12 @@
# define DISABLE_UMIP (1<<(X86_FEATURE_UMIP & 31))
#endif
+#ifdef CONFIG_X86_LASS
+# define DISABLE_LASS 0
+#else
+# define DISABLE_LASS (1<<(X86_FEATURE_LASS & 31))
+#endif
+
#ifdef CONFIG_X86_64
# define DISABLE_VME (1<<(X86_FEATURE_VME & 31))
# define DISABLE_K6_MTRR (1<<(X86_FEATURE_K6_MTRR & 31))
@@ -115,7 +121,7 @@
#define DISABLED_MASK10 0
#define DISABLED_MASK11 (DISABLE_RETPOLINE|DISABLE_RETHUNK|DISABLE_UNRET| \
DISABLE_CALL_DEPTH_TRACKING)
-#define DISABLED_MASK12 0
+#define DISABLED_MASK12 (DISABLE_LASS)
#define DISABLED_MASK13 0
#define DISABLED_MASK14 0
#define DISABLED_MASK15 0
--
2.34.1
next prev parent reply other threads:[~2023-01-10 5:57 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-10 5:51 [PATCH 0/7] Enable LASS (Linear Address space Separation) Yian Chen
2023-01-10 5:51 ` [PATCH 1/7] x86/cpu: Enumerate LASS CPUID and CR4 bits Yian Chen
2023-01-10 20:14 ` Sohil Mehta
2023-01-11 0:13 ` Dave Hansen
2023-01-11 23:23 ` Chen, Yian
2023-01-12 0:06 ` Luck, Tony
2023-01-12 0:15 ` Chen, Yian
2023-01-11 19:21 ` Chen, Yian
2023-01-10 5:51 ` Yian Chen [this message]
2023-01-10 21:05 ` [PATCH 2/7] x86: Add CONFIG option X86_LASS Sohil Mehta
2023-01-12 0:13 ` Chen, Yian
2023-01-10 5:52 ` [PATCH 3/7] x86/cpu: Disable kernel LASS when patching kernel alternatives Yian Chen
2023-01-10 21:04 ` Peter Zijlstra
2023-01-11 1:01 ` Chen, Yian
2023-01-11 9:10 ` Peter Zijlstra
2023-01-10 22:41 ` Sohil Mehta
2023-01-12 0:27 ` Chen, Yian
2023-01-12 0:37 ` Dave Hansen
2023-01-12 18:36 ` Chen, Yian
2023-01-12 18:48 ` Dave Hansen
2023-02-01 2:25 ` Sohil Mehta
2023-02-01 18:20 ` Dave Hansen
2023-02-01 2:10 ` Sohil Mehta
2023-01-10 5:52 ` [PATCH 4/7] x86/vsyscall: Setup vsyscall to compromise LASS protection Yian Chen
2023-01-11 0:34 ` Sohil Mehta
2023-01-12 1:43 ` Chen, Yian
2023-01-12 2:49 ` Sohil Mehta
2023-01-21 4:09 ` Andy Lutomirski
2023-01-10 5:52 ` [PATCH 5/7] x86/cpu: Enable LASS (Linear Address Space Separation) Yian Chen
2023-01-11 22:22 ` Sohil Mehta
2023-01-12 17:56 ` Chen, Yian
2023-01-12 18:17 ` Dave Hansen
2023-01-13 1:17 ` Sohil Mehta
2023-01-13 19:39 ` Sohil Mehta
2023-01-10 5:52 ` [PATCH 6/7] x86/cpu: Set LASS as pinning sensitive CR4 bit Yian Chen
2023-01-10 5:52 ` [PATCH 7/7] x86/kvm: Expose LASS feature to VM guest Yian Chen
2023-02-07 3:21 ` Wang, Lei
2023-02-09 17:18 ` Sean Christopherson
2023-01-10 19:48 ` [PATCH 0/7] Enable LASS (Linear Address space Separation) Sohil Mehta
2023-01-10 22:57 ` Dave Hansen
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