linux-kernel - [PATCH 5/5] KVM: svm: Set X86_FEATURE_NO

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20220916045832.461395-6-jmattson@google.com>
Date:   Thu, 15 Sep 2022 21:58:32 -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 5/5] KVM: svm: Set X86_FEATURE_NO_LMSLE when !nested

KVM has never allowed a guest to set EFER.LMSLE when the "nested"
module parameter was false. In the past, there was no way for a guest
to know whether or not this was a legal EFER bit. Now, we can let the
guest know this bit is illegal by reporting X86_FEATURE_NO_LMSLE in
KVM_GET_SUPPORTED_CPUID.

Signed-off-by: Jim Mattson <jmattson@...gle.com>
---
 arch/x86/kvm/svm/svm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 7c4fd594166c..942602d503ad 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4945,6 +4945,8 @@ static __init void svm_set_cpu_caps(void)
 	if (boot_cpu_has(X86_FEATURE_LS_CFG_SSBD) ||
 	    boot_cpu_has(X86_FEATURE_AMD_SSBD))
 		kvm_cpu_cap_set(X86_FEATURE_VIRT_SSBD);
+	if (!nested)
+		kvm_cpu_cap_set(X86_FEATURE_NO_LMSLE);
 
 	/* AMD PMU PERFCTR_CORE CPUID */
 	if (enable_pmu && boot_cpu_has(X86_FEATURE_PERFCTR_CORE))
-- 
2.37.3.968.ga6b4b080e4-goog