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    SubjectRE: Introducing paravirt_ops for x86_64
    Glauber de Oliveira Costa wrote:
    > On 8/8/07, Nakajima, Jun <> wrote:
    > > Glauber de Oliveira Costa wrote:
    > > > Hi folks,
    > > >
    > > > After some time away from it, and a big rebase as a consequence,
    here is
    > > > the updated version of paravirt_ops for x86_64, heading to
    > > >
    > > > Your criticism is of course, very welcome.
    > > >
    > > > Have fun
    > >
    > > Do you assume that the kernel ougtht to use 2MB pages for its
    > > (e.g. initilal text/data, direct mapping of physical memory) under
    > > paravirt_ops? As far as I look at the patches, I don't find one.
    > I don't think how it could be relevant here. lguest kernel does use
    > 2MB pages, and it goes smootly. For 2MB pages, we will update the page
    > tables in the very same way, and in the very places we did before.
    > Just that the operations can now be overwritten.
    > So, unless I'm very wrong, it only makes sense to talk about not
    > supporting large pages in the guest level. But it is not a
    > paravirt_ops problem.

    Some MMU-related PV techiniques (including Xen, and direct paging mode
    for Xen/KVM) need to write-protect page tables, avoiding to use 2MB
    pages when mapping page tables. Looks like you did not, and that
    exaplains why the patches are missing the relevant (many) paravirt_ops
    in include/asm-x86_64/pgalloc.h, for example, compared with the i386

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      Last update: 2007-08-09 02:35    [W:0.114 / U:51.344 seconds]
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