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    Subject[PATCH 3.16 004/254] KVM: x86: emulator: Return to user-mode on L1 CPL=0 emulation failure
    3.16.55-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Liran Alon <liran.alon@oracle.com>

    commit 1f4dcb3b213235e642088709a1c54964d23365e9 upstream.

    On this case, handle_emulation_failure() fills kvm_run with
    internal-error information which it expects to be delivered
    to user-mode for further processing.
    However, the code reports a wrong return-value which makes KVM to never
    return to user-mode on this scenario.

    Fixes: 6d77dbfc88e3 ("KVM: inject #UD if instruction emulation fails and exit to
    userspace")

    Signed-off-by: Liran Alon <liran.alon@oracle.com>
    Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
    Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
    Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    ---
    arch/x86/kvm/x86.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    --- a/arch/x86/kvm/x86.c
    +++ b/arch/x86/kvm/x86.c
    @@ -5009,7 +5009,7 @@ static int handle_emulation_failure(stru
    vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
    vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
    vcpu->run->internal.ndata = 0;
    - r = EMULATE_FAIL;
    + r = EMULATE_USER_EXIT;
    }
    kvm_queue_exception(vcpu, UD_VECTOR);

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