From: Jan Dakinevich jan.dakinevich@virtuozzo.com
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
--- arch/x86/kvm/emulate.c | 2 ++ arch/x86/kvm/x86.c | 6 ++++++ 2 files changed, 8 insertions(+)
--- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -5245,6 +5245,8 @@ 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; }
--- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5487,6 +5487,12 @@ int x86_emulate_instruction(struct kvm_v 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; }