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    SubjectRe: mmiotrace bug: recursive probe hit
    On Sat, 05 Apr 2008 10:36:50 +0300
    Avi Kivity <> wrote:

    > However there is a simpler (for you)
    > solution: run the driver-to-be-reverse-engineered in a kvm guest, and
    > modify kvm userspace to log accesses to mmio regions. This requires the
    > not-yet-merged pci passthrough support. You can reverse engineer
    > Windows drivers with this as well.

    This is a very interesting idea, I didn't know it would be possible.
    I think this also is a new project and I'd be happy to let someone else
    take it over. We could still use the log format and tools from
    mmiotrace, at least for starters.

    This puts mmiotrace in a new ligth: there's something better(?)
    coming in the future. But mmiotrace is here now, and I'd still like to
    see it in mainline. Within ftrace framework, mmiotrace will be very
    easy to use even for a Linux newbie. The KVM approach would be targeted
    to developers, as I suspect setting it up (even when everything has been
    merged into mainline) is more work than running mmiotrace.

    Ingo, what do you think? In my opinion let's make mmiotrace force the
    system down to UP via CPU hotplugging while MMIO tracing is active.
    This should guarantee reliable traces in the easiest way possible. The
    current workaround is not reliable on SMP. "Works enough" is what I'm
    thinking of.


    Pekka Paalanen

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      Last update: 2008-04-06 19:35    [W:0.020 / U:47.824 seconds]
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