linux-kernel - [RFC PATCH v2 08/33] KVM: SVM: Do not allow instruction emulation under SEV-ES

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Message-Id: <e06c1536f1bc6d34df5a683a7555d711051cb8d8.1601658176.git.thomas.lendacky@amd.com>
Date:   Fri,  2 Oct 2020 12:02:32 -0500
From:   Tom Lendacky <thomas.lendacky@....com>
To:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org, x86@...nel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Borislav Petkov <bp@...en8.de>, Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Brijesh Singh <brijesh.singh@....com>
Subject: [RFC PATCH v2 08/33] KVM: SVM: Do not allow instruction emulation under SEV-ES

From: Tom Lendacky <thomas.lendacky@....com>

When a guest is running as an SEV-ES guest, it is not possible to emulate
instructions. Add support to prevent instruction emulation.

Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
---
 arch/x86/kvm/svm/svm.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 5270735bbdd8..51041eb9758a 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4201,6 +4201,12 @@ static bool svm_can_emulate_instruction(struct kvm_vcpu *vcpu, void *insn, int i
 	bool smep, smap, is_user;
 	unsigned long cr4;
 
+	/*
+	 * When the guest is an SEV-ES guest, emulation is not possible.
+	 */
+	if (sev_es_guest(vcpu->kvm))
+		return false;
+
 	/*
 	 * Detect and workaround Errata 1096 Fam_17h_00_0Fh.
 	 *
-- 
2.28.0