Be a good citizen and don't allow any of the supported AMX xfeatures[1]
to be set if they can't all be set. That way userspace or a guest
doesn't fail if it attempts to set them in XCR0.
[1] CPUID.(EAX=0DH,ECX=0):EAX.XTILE_CFG[bit-17]
CPUID.(EAX=0DH,ECX=0):EAX.XTILE_DATA[bit-18]
Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Aaron Lewis <aaronlewis@xxxxxxxxxx>
---
arch/x86/kvm/cpuid.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 89ad8cd865173..bdccc4ddb45b1 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -866,6 +866,9 @@ static u64 sanitize_xcr0(u64 xcr0) {
if ((xcr0 & mask) != mask)
xcr0 &= ~XFEATURE_MASK_AVX512;
+ if ((xcr0 & XFEATURE_MASK_XTILE) != XFEATURE_MASK_XTILE)
+ xcr0 &= ~XFEATURE_MASK_XTILE;
+
return xcr0;
}
--
2.39.0.314.g84b9a713c41-goog
