mtrr_type_lookup(9)

💅 mtrr_type_lookup(9) — the kernel API manual, bestie edition 🎀

okay so welcome to the Kernel API Manual entry for mtrr_type_lookup — yes that's the <italic>mtrr_type_lookup(9)</italic> girlies know her 💖 this is lowkey the moment where we go look up a memory type in MTRR, and honestly? iconic.

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✨ NAME ✨

mtrr_type_lookup — look up memory type in MTRR 🔍✨

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🌸 SYNOPSIS 🌸

u8 mtrr_type_lookup (u64 start , u64 end , u8 *uniform );

that's the whole vibe. three args, one u8 return, no cap 🫶

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🦋 ARGUMENTS 🦋

• start — Begin of the physical address range 📍 like where the whole thing kicks off
• end — End of the physical address range 🏁 the finish line, bestie
• uniform — output argument, so she gives you something back 👑:
  • 1: the returned MTRR type is valid for the whole region ✅ the entire range, all of it, periodt
  • 0: otherwise 🙈 like, not the whole region, so don't get too comfortable
  • (and yeah, these two bullets are literally nested under uniform in the original because that's just how she is 💅)

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⭐ DESCRIPTION ⭐

here's the Return Values tea, and it's giving very clear 🌈:

• MTRR_TYPE_(type) — the effective MTRR type for the region 🔥 that's your answer
• MTRR_TYPE_INVALID — MTRR is disabled 💀 that's your "sorry babe, nothing here" answer

that's it, that's the description. short and stunning, we love a main character energy section that doesn't overstay its welcome 🧚

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💜 SEE ALSO 💜

• Kernel file ./arch/x86/kernel/cpu/mtrr/generic.c 📁 go read the source, iykyk
• guest_force_mtrr_state(9)
• set_fixed_range(9)
• generic_get_free_region(9)
• set_fixed_ranges(9)
• set_mtrr_state(9)
• generic_set_mtrr(9)

like a little friend group of functions, all linked together 🫶 go say hi to all of them fr fr

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lowkey reminder: uniform is an output argument, so don't go passing garbage and expecting magic — she writes back to it 👀

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okay that's the page 🍓!! huge thanks to the source dir ./arch/x86/kernel/cpu/mtrr and the October 2026 date stamp for making this little manual moment happen — version and date both said with love, mwah 💖✨ this has been mtrr_type_lookup(9), slay and goodbye 👑🌸