[PATCH v1 2/4] x86/cpuid: Add a dependency of AVX-IFMA on AVX

[Guixiong Wei]

AVX-IFMA is VEX-encoded and operates on the YMM registers, so it depends
on AVX, but it is missing from cpuid_deps[]. As a result, clearing AVX
(e.g. via "clearcpuid=", "noxsave" or the GDS mitigation) leaves AVX-IFMA
set, which KVM then advertises to guests without AVX - an inconsistent
CPUID state that check_cpufeature_deps() does not catch.

Add the missing dependency, following the existing convention that
VEX-encoded/YMM instructions depend on AVX (see AVX-VNNI, VAES and
VPCLMULQDQ).

Fixes: 5e85c4ebf206 ("x86: KVM: Advertise AVX-IFMA CPUID to user space")
Signed-off-by: Guixiong Wei <weiguixiong@xxxxxxxxxxxxx>
---
 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 e78d28a43ec7..6b1df617a423 100644
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -49,6 +49,7 @@ static const struct cpuid_dep cpuid_deps[] = {
 	{ X86_FEATURE_FMA,			X86_FEATURE_AVX       },
 	{ X86_FEATURE_VAES,			X86_FEATURE_AVX       },
 	{ X86_FEATURE_VPCLMULQDQ,		X86_FEATURE_AVX       },
+	{ X86_FEATURE_AVX_IFMA,			X86_FEATURE_AVX       },
 	{ X86_FEATURE_AVX2,			X86_FEATURE_AVX,      },
 	{ X86_FEATURE_AVX512F,			X86_FEATURE_AVX,      },
 	{ X86_FEATURE_AVX512IFMA,		X86_FEATURE_AVX512F   },
-- 
2.50.1 (Apple Git-155)