From 7fe864dc942c041cc4f56e287c4025d54a8e6c1e Mon Sep 17 00:00:00 2001
From: Nadav Amit <namit@cs.technion.ac.il>
Date: Mon, 2 Jun 2014 18:34:03 +0300
Subject: [PATCH] KVM: x86: Mark VEX-prefix instructions emulation as
unimplemented
Currently the emulator does not recognize vex-prefix instructions. However, it
may incorrectly decode lgdt/lidt instructions and try to execute them. This
patch returns unhandlable error on their emulation.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/emulate.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index e4e833d3d7d7..8ec4a3ebf403 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4314,6 +4314,13 @@ done_prefixes:
if (ctxt->d & ModRM)
ctxt->modrm = insn_fetch(u8, ctxt);
+ /* vex-prefix instructions are not implemented */
+ if (ctxt->opcode_len == 1 && (ctxt->b == 0xc5 || ctxt->b == 0xc4) &&
+ (mode == X86EMUL_MODE_PROT64 ||
+ (mode >= X86EMUL_MODE_PROT16 && (ctxt->modrm & 0x80)))) {
+ ctxt->d = NotImpl;
+ }
+
while (ctxt->d & GroupMask) {
switch (ctxt->d & GroupMask) {
case Group:
--
2.34.1