From: Jan Dakinevich <jan.dakinevich@virtuozzo.com>
Date: Tue, 27 Aug 2019 13:07:08 +0000 (+0000)
Subject: KVM: x86: set ctxt->have_exception in x86_decode_insn()
X-Git-Tag: v4.19.77~46
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=933e3e2b5070058097089d77281ce2704d031070;p=platform%2Fkernel%2Flinux-rpi.git

KVM: x86: set ctxt->have_exception in x86_decode_insn()

commit c8848cee74ff05638e913582a476bde879c968ad upstream.

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: 6ea6e84309ca ("KVM: x86: inject exceptions produced by x86_decode_insn")
Cc: stable@vger.kernel.org
Cc: Denis Lunev <den@virtuozzo.com>
Cc: Roman Kagan <rkagan@virtuozzo.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Signed-off-by: Jan Dakinevich <jan.dakinevich@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 429728b..e699f4d 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -5368,6 +5368,8 @@ done_prefixes:
 					ctxt->memopp->addr.mem.ea + ctxt->_eip);
 
 done:
+	if (rc == X86EMUL_PROPAGATE_FAULT)
+		ctxt->have_exception = true;
 	return (rc != X86EMUL_CONTINUE) ? EMULATION_FAILED : EMULATION_OK;
 }
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a8892f7..162fed4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6245,6 +6245,12 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu,
 						emulation_type))
 				return EMULATE_DONE;
 			if (ctxt->have_exception) {
+				/*
+				 * #UD should result in just EMULATION_FAILED, and trap-like
+				 * exception should not be encountered during decode.
+				 */
+				WARN_ON_ONCE(ctxt->exception.vector == UD_VECTOR ||
+					     exception_type(ctxt->exception.vector) == EXCPT_TRAP);
 				inject_emulated_exception(vcpu);
 				return EMULATE_DONE;
 			}