to_pos(9)

✨ to_pos(9) ✨

okay so bestie, welcome to the to_pos page from the Kernel API Manual — it's giving "tiny function, very specific job," and honestly? We respect it. 💅

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🌸 NAME 🌸

to_pos — extract an interleave position from an HPA offset. That's it, that's the whole vibe. 🎀

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🦋 SYNOPSIS 🦋

u64 to_pos (u64 hpa_offset , u8 r_eiw , u16 r_eig , u8 hb_ways , u8 math
);

literally the whole signature, no cap. Note the very chic line break before that last ); — that's just how it is. 💖

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🌈 ARGUMENTS 🌈

okay so the original page is lowkey mysterious about these, and we are not gonna invent lore. Every single one is listed as -- undescribed --:

• hpa_offset — -- undescribed --
• r_eiw — -- undescribed --
• r_eig — -- undescribed --
• hb_ways — -- undescribed --
• math — -- undescribed --

like… the AUDACITY of leaving us on read 😭 but we're keeping it exactly as written. No guessing, no extra tips, periodt.

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💜 DESCRIPTION 💜

okay so here's where the page actually spills:

• hpa_offset: host physical address offset
• r_eiw: region encoded interleave ways
• r_eig: region encoded interleave granularity
• hb_ways: host bridge interleave ways
• math: interleave arithmetic (MODULO_MATH or XOR_MATH)

so yes, those five mystery arguments from above do have meanings — they're just all crammed into the description instead of the argument list. iconic formatting choice, honestly. 💀

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⭐ RETURN ⭐

devices position in region interleave 🫶

that's the return value, bestie. short, sweet, and serving exactly one job.

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👑 SEE ALSO 👑

• Kernel file ./tools/testing/cxl/test/cxl_translate.c
• to_hpa(9)
• to_dpa(9)
• run_translation_test(9)
• parse_test_vector(9)

go read those if you wanna complete the lore arc 📚✨

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warning-ish reminder: this page gives us zero extra details beyond what's above — no hidden defaults, no secret edge cases, no extra behaviour claims. if you need more, the SEE ALSO girlies are right there. 💅

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and that's the whole page, bestie — go off, translate those addresses, and slay 💖

source/version vibes: ./tools/testing/cxl/test, dated October 2026, and the manual name is to_pos(9) — mwah, signed, sealed, delivered. 🎀🦋💜