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    SubjectRe: [RFC, PATCH 16/24] i386 Vmi io header
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    Zachary Amsden <zach@vmware.com> writes:

    > Move I/O instruction building to the sub-arch layer. Some very crafty
    > but esoteric macros are used here to get optimized native instructions
    > for port I/O in Linux be writing raw instruction strings. Adding a
    > wrapper layer here is fairly easy, and makes the full range of I/O
    > instructions available to the VMI interface.
    >
    > Also, slowing down I/O is not a useful operation in a VM, so there
    > is a VMI call specifically to allow making it a NOP. I could find
    > no place where SLOW_IO_BY_JUMPING is still used, and consider it
    > obsoleted. Even on older 386 systems, the I/O delay approximation
    > by touching the extra page register is likely to better.

    This sounds like a prime candidate for the alternate instruction interfaces
    and I don't see that being used here.

    Eric
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