[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] RFC : 4KiB page support - x86_32.S
> I see few issues. > > For one thing PAGE_OFFSET points to "4gb - 60mb" and 60mb. This is where > the current page table stuff live. This is fine with 4mb pages as in this > configuration page table/directory occupy only 4kb. > > However, once I want to duplicate current setup using 4kb of pages, I need > 4MB for page tables (+4kb for page directory). > > It seems to me that once I have 4mb of page tables + other stuff from > x86_32.S I would run over the 4gb mark (although with a bit of empirical > testing it did not crash right away.. not sure If I'm missing something.). > > I have tried to change PAGE_OFFSET to point to "4gb - 56", but then all > hell would break lose and it would not even work with 4mb pages on pentium > 3. > > Thus in my code I just put the 4mb wroth of page tables at 56mb-60mb > address space, what should fit well with both low and high memory. It > seems to work fine other than it just my idea to use this particular space > for the page. 56-60mb is probably okay, but kernel.c will need fixing because I think it currently copies dom0 image there temporarily during Xen bootstrap. As you say, checking CPUID is a good idea. mmu_cr4_features is initialised statically as a C variable. I'll try to find time to take a closer look and hopefully get 4kb-page support checked in. Cheers, Keir ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://productguide.itmanagersjournal.com/ _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/xen-devel
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