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    SubjectRe: [PATCH 10/28] i386: map enough initial memory to create lowmem mappings
    Eric W. Biederman wrote:
    > Consider a memory hole of size 8M immediately after our bootmem bitmap.
    > head.S which knows nothing of holes will map the pages of the hole
    > into the initial page tables assuming that is where the page tables
    > will live.
    >

    Sure, but considering we're only talking about mapping an additional *2*
    pages, the chances are that it will affect a kernel as much as the early
    head.S mapping. It's well within the variability of fairly similar
    kernel configs.

    > As for how to fix this, we need to call boot_ioremap or better
    > bt_ioremap on the address returned from alloc_bootmem_pages_low to
    > force the allocated page into the page table. After we have setup
    > the page table page we can call unmap the page to free up the scarce
    > early mapping resource.
    >

    Would that be necessary? Is there any need to remap it? Couldn't you
    just do the straightforward phys->virt mapping and use the page where it
    lies?

    J
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