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| author | Nadav Amit <namit@cs.technion.ac.il> | 2014-08-13 16:50:13 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-08-19 15:12:28 +0200 |
| commit | 3a6095a0173ad8f20c508446880558c9f9224324 (patch) | |
| tree | 4725c419f4a5cfe54f20e9f0d80ea3efa6476c34 | |
| parent | c04fa5831d4d89dfbc88406f4a46f9846841a560 (diff) | |
| download | op-kernel-dev-3a6095a0173ad8f20c508446880558c9f9224324.zip op-kernel-dev-3a6095a0173ad8f20c508446880558c9f9224324.tar.gz | |
KVM: x86: Avoid emulating instructions on #UD mistakenly
Commit d40a6898e5 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: Nadav Amit <namit@cs.technion.ac.il>
[Tweak operand order in &&, remove EmulateOnUD where it's now superfluous.
- Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/kvm/emulate.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 56657b0..ef117b8 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -4394,8 +4394,11 @@ done_prefixes: ctxt->execute = opcode.u.execute; + if (unlikely(ctxt->ud) && likely(!(ctxt->d & EmulateOnUD))) + return EMULATION_FAILED; + 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 * in x86_emulate_insn. @@ -4406,9 +4409,6 @@ done_prefixes: if (ctxt->d & NotImpl) return EMULATION_FAILED; - if (!(ctxt->d & EmulateOnUD) && ctxt->ud) - return EMULATION_FAILED; - if (mode == X86EMUL_MODE_PROT64 && (ctxt->d & Stack)) ctxt->op_bytes = 8; |
