linux-kernel - [PATCH RESEND v4 12/23] KVM: x86: emulator: update the emulation mode after rsm

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Message-Id: <20221025124741.228045-13-mlevitsk@redhat.com>
Date:   Tue, 25 Oct 2022 15:47:30 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     kvm@...r.kernel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Yang Zhong <yang.zhong@...el.com>, x86@...nel.org,
        Jim Mattson <jmattson@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Shuah Khan <shuah@...nel.org>,
        Guang Zeng <guang.zeng@...el.com>,
        Joerg Roedel <joro@...tes.org>,
        Maxim Levitsky <mlevitsk@...hat.com>,
        linux-kernel@...r.kernel.org,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Ingo Molnar <mingo@...hat.com>,
        linux-kselftest@...r.kernel.org, Kees Cook <keescook@...omium.org>,
        "H. Peter Anvin" <hpa@...or.com>, Wei Wang <wei.w.wang@...el.com>,
        Borislav Petkov <bp@...en8.de>
Subject: [PATCH RESEND v4 12/23] KVM: x86: emulator: update the emulation mode after rsm

Update the emulation mode after RSM so 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@...hat.com>
---
 arch/x86/kvm/emulate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index c65f57b6da9bf1..2c56d08b426065 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2315,7 +2315,7 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt)
 	if (ctxt->ops->leave_smm(ctxt))
 		ctxt->ops->triple_fault(ctxt);
 
-	return X86EMUL_CONTINUE;
+	return emulator_recalc_and_set_mode(ctxt);
 }
 
 static void
-- 
2.34.3