Commit 3a6095a0 authored by Nadav Amit's avatar Nadav Amit Committed by Paolo Bonzini

KVM: x86: Avoid emulating instructions on #UD mistakenly

Commit d40a6898 mistakenly caused instructions which are not marked as
EmulateOnUD to be emulated upon #UD exception. The commit caused the check of
whether the instruction flags include EmulateOnUD to never be evaluated. As a
result instructions whose emulation is broken may be emulated.  This fix moves
the evaluation of EmulateOnUD so it would be evaluated.
Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
[Tweak operand order in &&, remove EmulateOnUD where it's now superfluous.
 - Paolo]
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent c04fa583
...@@ -4394,8 +4394,11 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) ...@@ -4394,8 +4394,11 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
ctxt->execute = opcode.u.execute; ctxt->execute = opcode.u.execute;
if (unlikely(ctxt->ud) && likely(!(ctxt->d & EmulateOnUD)))
return EMULATION_FAILED;
if (unlikely(ctxt->d & if (unlikely(ctxt->d &
(NotImpl|EmulateOnUD|Stack|Op3264|Sse|Mmx|Intercept|CheckPerm))) { (NotImpl|Stack|Op3264|Sse|Mmx|Intercept|CheckPerm))) {
/* /*
* These are copied unconditionally here, and checked unconditionally * These are copied unconditionally here, and checked unconditionally
* in x86_emulate_insn. * in x86_emulate_insn.
...@@ -4406,9 +4409,6 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) ...@@ -4406,9 +4409,6 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
if (ctxt->d & NotImpl) if (ctxt->d & NotImpl)
return EMULATION_FAILED; return EMULATION_FAILED;
if (!(ctxt->d & EmulateOnUD) && ctxt->ud)
return EMULATION_FAILED;
if (mode == X86EMUL_MODE_PROT64 && (ctxt->d & Stack)) if (mode == X86EMUL_MODE_PROT64 && (ctxt->d & Stack))
ctxt->op_bytes = 8; ctxt->op_bytes = 8;
......
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