linux-kernel - [PATCH 1/3] KVM: SVM: #SMI interception must not skip the instruction

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]

Date:   Wed,  7 Jul 2021 15:50:58 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     kvm@...r.kernel.org
Cc:     Joerg Roedel <joro@...tes.org>, Borislav Petkov <bp@...en8.de>,
        Sean Christopherson <seanjc@...gle.com>,
        x86@...nel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
        "H. Peter Anvin" <hpa@...or.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org, Jim Mattson <jmattson@...gle.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Ingo Molnar <mingo@...hat.com>,
        Maxim Levitsky <mlevitsk@...hat.com>
Subject: [PATCH 1/3] KVM: SVM: #SMI interception must not skip the instruction

Commit 5ff3a351f687 ("KVM: x86: Move trivial instruction-based
exit handlers to common code"), unfortunately made a mistake of
treating nop_on_interception and nop_interception in the same way.

Former does truly nothing while the latter skips the instruction.

SMI VM exit handler should do nothing.
(SMI itself is handled by the host when we do STGI)

Fixes: 5ff3a351f687 ("KVM: x86: Move trivial instruction-based exit handlers to common code")
Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>
---
 arch/x86/kvm/svm/svm.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 616b9679ddcc..41d0a589c578 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2127,6 +2127,11 @@ static int nmi_interception(struct kvm_vcpu *vcpu)
 	return 1;
 }
 
+static int smi_interception(struct kvm_vcpu *vcpu)
+{
+	return 1;
+}
+
 static int intr_interception(struct kvm_vcpu *vcpu)
 {
 	++vcpu->stat.irq_exits;
@@ -3101,7 +3106,7 @@ static int (*const svm_exit_handlers[])(struct kvm_vcpu *vcpu) = {
 	[SVM_EXIT_EXCP_BASE + GP_VECTOR]	= gp_interception,
 	[SVM_EXIT_INTR]				= intr_interception,
 	[SVM_EXIT_NMI]				= nmi_interception,
-	[SVM_EXIT_SMI]				= kvm_emulate_as_nop,
+	[SVM_EXIT_SMI]				= smi_interception,
 	[SVM_EXIT_INIT]				= kvm_emulate_as_nop,
 	[SVM_EXIT_VINTR]			= interrupt_window_interception,
 	[SVM_EXIT_RDPMC]			= kvm_emulate_rdpmc,
-- 
2.26.3