[PATCHv6 14/16] x86/cpu: Make LAM depend on LASS

Kirill A. Shutemov
2025-06-20T13:53:53Z

From: Alexander Shishkin <alexander.shishkin@linux.intel.com>

To prevent exploits for Spectre based on LAM as demonstrated by the
whitepaper [1], make LAM depend on LASS, which avoids this type of
vulnerability.

[1] https://download.vusec.net/papers/slam_sp24.pdf

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
arch/x86/kernel/cpu/cpuid-deps.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
index 98d0cdd82574..11bb9ed40140 100644
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -90,6 +90,7 @@ static const struct cpuid_dep cpuid_deps[] = {
{ X86_FEATURE_FRED, X86_FEATURE_LKGS },
{ X86_FEATURE_SPEC_CTRL_SSBD, X86_FEATURE_SPEC_CTRL },
{ X86_FEATURE_LASS, X86_FEATURE_SMAP },
+ { X86_FEATURE_LAM, X86_FEATURE_LASS },
{}
};

--
2.47.2