• James Hogan's avatar
    KVM: MIPS/VZ: Trace guest mode changes · edec9d7b
    James Hogan authored
    Create a trace event for guest mode changes, and enable VZ's
    GuestCtl0.MC bit after the trace event is enabled to trap all guest mode
    changes.
    
    The MC bit causes Guest Hardware Field Change (GHFC) exceptions whenever
    a guest mode change occurs (such as an exception entry or return from
    exception), so we need to handle this exception now. The MC bit is only
    enabled when restoring register state, so enabling the trace event won't
    take immediate effect.
    
    Tracing guest mode changes can be particularly handy when trying to work
    out what a guest OS gets up to before something goes wrong, especially
    if the problem occurs as a result of some previous guest userland
    exception which would otherwise be invisible in the trace.
    Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
    Cc: Paolo Bonzini <pbonzini@redhat.com>
    Cc: "Radim Krčmář" <rkrcmar@redhat.com>
    Cc: Steven Rostedt <rostedt@goodmis.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Ralf Baechle <ralf@linux-mips.org>
    Cc: linux-mips@linux-mips.org
    Cc: kvm@vger.kernel.org
    edec9d7b
mips.c 41.9 KB