lkml.org 
[lkml]   [2007]   [Aug]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRE: Introducing paravirt_ops for x86_64
    Date
    From
    Glauber de Oliveira Costa wrote:
    > On 8/8/07, Nakajima, Jun <jun.nakajima@intel.com> 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
    inclusion.
    > > >
    > > > Your criticism is of course, very welcome.
    > > >
    > > > Have fun
    > >
    > > Do you assume that the kernel ougtht to use 2MB pages for its
    mappings
    > > (e.g. initilal text/data, direct mapping of physical memory) under
    your
    > > 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
    tree.

    Jun
    ---
    Intel Open Source Technology Center
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2007-08-09 02:35    [W:0.023 / U:1.392 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site