vfio_check_feature(9)

✨ vfio_check_feature(9) ✨

okay bestie, so this is a page from the Kernel API Manual and it's literally about vfio_check_feature — the lil helper that does the vibe check on user input before the VFIO_DEVICE_FEATURE ioctl gets to run 💅

🌸 NAME 🌸

vfio_check_feature — validate user input for the VFIO_DEVICE_FEATURE ioctl

Like, it's the bouncer at the club door for your ioctl args 🫶

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🦋 SYNOPSIS 🦋

int vfio_check_feature (u32 flags , size_t argsz , u32 supported_ops ,
       size_t minsz );

🎀 ARGUMENTS 🎀

• flags — the flags arg from the device_feature op 💫
• argsz — the argsz arg from the device_feature op 💫
• supported_ops — a combination of VFIO_DEVICE_FEATURE_GET and SET that the driver supports 👑
• minsz — the minimum data size the driver accepts, no cap 🍓

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🌈 DESCRIPTION 🌈

So this one is for use in a driver's device_feature op, iykyk. It checks that the inputs going into the VFIO_DEVICE_FEATURE ioctl are actually correct for the driver's feature ✨

It returns 1 if the driver should go ahead and execute the get or set — main character energy, go off 🎉 Otherwise, the relevant value should be returned instead 💀

ngl, that's the whole thing. small function, big responsibility 🔥

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💖 SEE ALSO 💖

• Kernel file ./include/linux/vfio.h — struct vfio_device_ops(9), struct vfio_migration_ops(9), struct vfio_log_ops(9), vfio_check_precopy_ioctl(9) 🦋

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and that's the page, bestie!! 🥳 this one's brought to you by ./include/linux, dated October 2026, and it's literally vfio_check_feature(9) — go read the whole series, mwah 💜🎀