linux-kernel - [PATCH] x86/cpufeatures: Fix dependencies for GFNI, VAES, and VPCLMULQDQ

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Message-ID: <20240417060434.47101-1-ebiggers@kernel.org>
Date: Tue, 16 Apr 2024 23:04:34 -0700
From: Eric Biggers <ebiggers@...nel.org>
To: x86@...nel.org
Cc: linux-crypto@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] x86/cpufeatures: Fix dependencies for GFNI, VAES, and VPCLMULQDQ

From: Eric Biggers <ebiggers@...gle.com>

Fix cpuid_deps[] to list the correct dependencies for GFNI, VAES, and
VPCLMULQDQ.  These features don't depend on AVX512, and there exist CPUs
that support these features but not AVX512.  GFNI actually doesn't even
depend on AVX.

This prevents GFNI from being unnecessarily disabled if AVX is disabled
to mitigate the GDS vulnerability.

This also prevents all three features from being unnecessarily disabled
if AVX512VL (or its dependency AVX512F) were to be disabled, but it
looks like there isn't any case where this happens anyway.

Fixes: c128dbfa0f87 ("x86/cpufeatures: Enable new SSE/AVX/AVX512 CPU features")
Signed-off-by: Eric Biggers <ebiggers@...gle.com>
---
 arch/x86/kernel/cpu/cpuid-deps.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
index b7174209d855..946813d816bf 100644
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -42,11 +42,14 @@ static const struct cpuid_dep cpuid_deps[] = {
 	{ X86_FEATURE_PCLMULQDQ,		X86_FEATURE_XMM2      },
 	{ X86_FEATURE_SSSE3,			X86_FEATURE_XMM2,     },
 	{ X86_FEATURE_F16C,			X86_FEATURE_XMM2,     },
 	{ X86_FEATURE_AES,			X86_FEATURE_XMM2      },
 	{ X86_FEATURE_SHA_NI,			X86_FEATURE_XMM2      },
+	{ X86_FEATURE_GFNI,			X86_FEATURE_XMM2      },
 	{ X86_FEATURE_FMA,			X86_FEATURE_AVX       },
+	{ X86_FEATURE_VAES,			X86_FEATURE_AVX       },
+	{ X86_FEATURE_VPCLMULQDQ,		X86_FEATURE_AVX       },
 	{ X86_FEATURE_AVX2,			X86_FEATURE_AVX,      },
 	{ X86_FEATURE_AVX512F,			X86_FEATURE_AVX,      },
 	{ X86_FEATURE_AVX512IFMA,		X86_FEATURE_AVX512F   },
 	{ X86_FEATURE_AVX512PF,			X86_FEATURE_AVX512F   },
 	{ X86_FEATURE_AVX512ER,			X86_FEATURE_AVX512F   },
@@ -54,13 +57,10 @@ static const struct cpuid_dep cpuid_deps[] = {
 	{ X86_FEATURE_AVX512DQ,			X86_FEATURE_AVX512F   },
 	{ X86_FEATURE_AVX512BW,			X86_FEATURE_AVX512F   },
 	{ X86_FEATURE_AVX512VL,			X86_FEATURE_AVX512F   },
 	{ X86_FEATURE_AVX512VBMI,		X86_FEATURE_AVX512F   },
 	{ X86_FEATURE_AVX512_VBMI2,		X86_FEATURE_AVX512VL  },
-	{ X86_FEATURE_GFNI,			X86_FEATURE_AVX512VL  },
-	{ X86_FEATURE_VAES,			X86_FEATURE_AVX512VL  },
-	{ X86_FEATURE_VPCLMULQDQ,		X86_FEATURE_AVX512VL  },
 	{ X86_FEATURE_AVX512_VNNI,		X86_FEATURE_AVX512VL  },
 	{ X86_FEATURE_AVX512_BITALG,		X86_FEATURE_AVX512VL  },
 	{ X86_FEATURE_AVX512_4VNNIW,		X86_FEATURE_AVX512F   },
 	{ X86_FEATURE_AVX512_4FMAPS,		X86_FEATURE_AVX512F   },
 	{ X86_FEATURE_AVX512_VPOPCNTDQ,		X86_FEATURE_AVX512F   },

base-commit: 20cb38a7af88dc40095da7c2c9094da3873fea23
-- 
2.44.0