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    SubjectRe: [patch] x86, pat: fix reserve_memtype() for legacy 1MB range
    Suresh Siddha wrote:
    > On Fri, Jan 09, 2009 at 02:39:31PM -0800, H. Peter Anvin wrote:
    >> Suresh Siddha wrote:
    >>> Here X is trying to map first 8KB of memory using /dev/mem. Existing
    >>> code treats first 0-4KB of memory as non-RAM and 4KB-8KB as RAM. Recent
    >>> code changes don't allow to map memory with different attributes
    >>> at the same time.
    >> Why was 0-4 KB marked as non-RAM? It is most definitely RAM, and should
    >> be WB.
    > While in reality it is RAM, we have CONFIG_STRICT_DEVMEM which doesn't allow
    > apps to map RAM pages using /dev/mem. And to allow app's to map the
    > legacy 0-4KB bios data page, we consider it as non-RAM.

    Permission to map and memory type should not be connected. Just to
    clarify, when mapped, was it still WB?


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