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    SubjectRe: [GIT PULL] x86: unify sys_iopl
    On 10/13/2009 09:53 AM, Jeremy Fitzhardinge wrote:
    > On 10/13/09 09:24, H. Peter Anvin wrote:
    >> First of all, the unification looks good.
    >>
    >> As far as .32 is concerned... this *is* a bug even if this is only for
    >> paravirt, and given the small amount of code I am personally OK with
    >> taking the whole patch for .32.
    >>
    >> However, the patch is not complete! The patch incidentally eliminates
    >> the need to have assembly stubs for sys_iopl, and those assembly stubs
    >> should be removed. I have a patch for that currently test building.
    >>
    >
    > I wasn't sure whether task_pt_regs() needed the full register set to be
    > saved to correctly return rflags (that is, does PTREGSCALL change the
    > shape of the stack, or just the contents?).
    >

    Erk, I was right but still wrong... it isn't safe to modify the partial
    pt_regs because of the magic sync stuff that goes on in entry_64.S.

    I have to say the entry_64.S stuff gives me a headache in the extreme.
    It really can't be the sanest way to do this stuff.

    /me makes a mental note to try to work through this code at some point.

    -hpa

    --
    H. Peter Anvin, Intel Open Source Technology Center
    I work for Intel. I don't speak on their behalf.



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