Re: PAE xen + linux kernel boots ...

[Gerd Knorr <kraxel@bytesex.org>]

Gerd Knorr <kraxel@bytesex.org> writes:

> ... linux userspace doesn't come up yet though, thus it is still some
> way to go.

Well, now it does, boots up to a login prompt ;)

>   Xen: http://dl.bytesex.org/patches/xen-4/pae-support
>   Linux: http://dl.bytesex.org/patches/linux-xen-4/

New versions of the patches are in xen-5 + linux-xen-5, they are
against changeset 1.1385 (xen) 2.6.11 vanilla (linux-xen).

Currently open issues are:

  * general: more testing, cleanups, drop debug code, review
    all the FIXME's in the code ...

  * interfaces: do_update_va_mapping() and do_mmu_update() use 32bit
    values for page table entry updates, which will stop working as
    soon as we'll attempt to use memory above 4GB (which isn't the
    case yet).

  * xen: quite a few places are not fixed yet to deal with physical
    addresses above 4GB, i.e. are still 32 bit only.

  * xen: writable pagetables need fixing, they use emulation at the
    moment.  I was very surprised that it did "just work", but that
    was just the bug fixed by Keir recently causing the code do
    emulation all the time ;-)

  * xenlinux: Not sure how to deal best with the vsyscall page.
    xenlinux places it just before the hypervisor area, which is a
    different address in pae/non-pae mode.  And there seems to be no
    obvious way to make that depend on CONFIG_X86_PAE, the linker
    script where the address is in is not processed by cpp ...

I think that's it for the moment.  Comments are welcome.

Enjoy,

  Gerd

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