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From:   Maxim Levitsky <mlevitsk@redhat.com>
To:     kvm@vger.kernel.org
Cc:     Sean Christopherson <seanjc@google.com>, x86@kernel.org,
        Kees Cook <keescook@chromium.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        linux-kernel@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
        Borislav Petkov <bp@alien8.de>, Joerg Roedel <joro@8bytes.org>,
        Ingo Molnar <mingo@redhat.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Maxim Levitsky <mlevitsk@redhat.com>
Subject: [PATCH v2 04/11] KVM: x86: emulator: update the emulation mode after rsm
Date:   Tue, 21 Jun 2022 18:08:55 +0300
Message-Id: <20220621150902.46126-5-mlevitsk@redhat.com>
In-Reply-To: <20220621150902.46126-1-mlevitsk@redhat.com>
References: <20220621150902.46126-1-mlevitsk@redhat.com>
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This ensures that RIP will be correctly written back,
because the RSM instruction can switch the CPU mode from
32 bit (or less) to 64 bit.

This fixes a guest crash in case the #SMI is received
while the guest runs a code from an address > 32 bit.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 arch/x86/kvm/emulate.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 334a06e6c9b093..6f4632babc4cd8 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2662,6 +2662,11 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt)
 	if (ret != X86EMUL_CONTINUE)
 		goto emulate_shutdown;
 
+
+	ret = update_emulation_mode(ctxt);
+	if (ret != X86EMUL_CONTINUE)
+		goto emulate_shutdown;
+
 	/*
 	 * Note, the ctxt->ops callbacks are responsible for handling side
 	 * effects when writing MSRs and CRs, e.g. MMU context resets, CPUID
-- 
2.26.3