From 7fe864dc942c041cc4f56e287c4025d54a8e6c1e Mon Sep 17 00:00:00 2001 From: Nadav Amit 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 Signed-off-by: Paolo Bonzini --- 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: -- 2.20.1