linux-kernel - [PATCH 4/5] KVM: x86: Enforce X86_FEATURE_NO

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Date:   Thu, 15 Sep 2022 21:58:31 -0700
From:   Jim Mattson <jmattson@...gle.com>
To:     Avi Kivity <avi@...hat.com>, Babu Moger <babu.moger@....com>,
        Borislav Petkov <bp@...en8.de>,
        "Chang S. Bae" <chang.seok.bae@...el.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
        Joerg Roedel <joerg.roedel@....com>,
        Josh Poimboeuf <jpoimboe@...nel.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>,
        Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Sean Christopherson <seanjc@...gle.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Wyes Karny <wyes.karny@....com>, x86@...nel.org
Cc:     Jim Mattson <jmattson@...gle.com>
Subject: [PATCH 4/5] KVM: x86: Enforce X86_FEATURE_NO_LMSLE in guest cpuid

When the guest CPUID reports that EFER.LMSLE is not supported, treat the
bit as reserved.

Signed-off-by: Jim Mattson <jmattson@...gle.com>
---
 arch/x86/kvm/x86.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 43a6a7efc6ec..26c4ca73e389 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1686,6 +1686,9 @@ static bool __kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer)
 	if (efer & EFER_NX && !guest_cpuid_has(vcpu, X86_FEATURE_NX))
 		return false;
 
+	if (efer & EFER_LMSLE && guest_cpuid_has(vcpu, X86_FEATURE_NO_LMSLE))
+		return false;
+
 	return true;
 
 }
-- 
2.37.3.968.ga6b4b080e4-goog