vfio_file_enforced_coherent(9)

✨ vfio_file_enforced_coherent ✨

okay bestie, welcome to the Kernel API Manual entry for vfio_file_enforced_coherent — yes that's a whole mouthful, yes it's giving main character energy, and yes we're gonna get through it together 🫶

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💖 NAME 💖

vfio_file_enforced_coherent — returns true if the DMA associated with the VFIO file is always CPU cache coherent 💅

like, always always. no cap.

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🌸 SYNOPSIS 🌸

bool vfio_file_enforced_coherent (struct file *file );

that's it. one function, one argument, returns a bool. iconic behavior honestly ✨

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🎀 ARGUMENTS 🎀

• file — a VFIO group file or a VFIO device file 🦋 (either one works, she's flexible like that)

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🧚 DESCRIPTION 🧚

so what does "enforced coherency" even mean, you ask? bestie, I'm so glad you did 💜

Enforced coherency means the IOMMU ignores things like the PCIe no-snoop bit in DMA transactions. like, it literally does not care, it's above all that drama 🙈

A return of false indicates that the user has rights to access additional instructions such as wbinvd on x86 👑

⚠️ lowkey important: false here isn't just "nope, not coherent" — it's telling you the user has extra instruction access. read the return value carefully, bestie, it's carrying a lot of lore 💀

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🔥 SEE ALSO 🔥

• Kernel file ./drivers/vfio/vfio_main.c
• vfio_file_is_valid(9)
• vfio_file_set_kvm(9)

go read those next, iykyk 🌈

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and that's the whole page, periodt 💅 this was vfio_file_enforced_coherent(9) from the Kernel API Manual, sourced from ./drivers/vfio, dated October 2026 — mwah, go touch some DMA transactions 🍓💖