linux-kernel - [PATCH v2 3/3] KVM: x86: set ctxt->have_exception in x86_decode

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Date:   Wed, 28 Aug 2019 17:02:59 +0000
From:   Jan Dakinevich <jan.dakinevich@...tuozzo.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Jan Dakinevich <jan.dakinevich@...tuozzo.com>,
        Denis Lunev <den@...tuozzo.com>,
        Roman Kagan <rkagan@...tuozzo.com>,
        Denis Plotnikov <dplotnikov@...tuozzo.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>
Subject: [PATCH v2 3/3] KVM: x86: set ctxt->have_exception in
 x86_decode_insn()

x86_emulate_instruction() takes into account ctxt->have_exception flag
during instruction decoding, but in practice this flag is never set in
x86_decode_insn().

Fixes: 6ea6e84 ("KVM: x86: inject exceptions produced by x86_decode_insn")
Cc: Denis Lunev <den@...tuozzo.com>
Cc: Roman Kagan <rkagan@...tuozzo.com>
Cc: Denis Plotnikov <dplotnikov@...tuozzo.com>
Signed-off-by: Jan Dakinevich <jan.dakinevich@...tuozzo.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 bef3c3c..74b4d79 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -5416,6 +5416,11 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
 					ctxt->memopp->addr.mem.ea + ctxt->_eip);
 
 done:
+	if (rc == X86EMUL_PROPAGATE_FAULT) {
+		WARN_ON_ONCE(ctxt->exception.vector == UD_VECTOR ||
+			     exception_type(ctxt->exception.vector) == EXCPT_TRAP);
+		ctxt->have_exception = true;
+	}
 	return (rc != X86EMUL_CONTINUE) ? EMULATION_FAILED : EMULATION_OK;
 }
 
-- 
2.1.4