xe_migrate_c...w_copy_clear(9)

📦 version 7.3.1, in nixpkgs unstable

💅 xe_migrate_ccs_rw_copy_clear — a Kernel API Manual moment (section 9, bestie)

okay so real talk, this page lives in the Kernel API Manual, section 9, and it's here to explain xe_migrate_ccs_rw_copy_clear — a function whose whole personality is clearing out the CCS read/write batch buffer content. no cap, that's the whole vibe. 🎀

✨ NAME ✨

xe_migrate_ccs_rw_copy_clear — literally clears the CCS read/write batch buffer content. that's it, that's the job. 🧹💖

✨ SYNOPSIS ✨

void xe_migrate_ccs_rw_copy_clear (struct xe_bo *src_bo , enum
       xe_sriov_vf_ccs_rw_ctxs read_write , bool bound );

three args, one void, zero crumbs. slay. 🔥

✨ ARGUMENTS ✨

  • src_bo — the buffer object that src is currently bound to. like, that's its whole thing rn. 🫶
  • read_write — of type enum xe_sriov_vf_ccs_rw_ctxs, and it's the one that decides whether we're making BB commands for a CCS read or a CCS write. iykyk. 💅
  • bound — a bool that says whether the device is bound. yes or no, iconic either way. ⭐

✨ DESCRIPTION ✨

okay so bestie, here's the tea. if you just clear the BB directly, you get no atomicity, and that's a problem — because if the vCPU gets halted mid-operation while the clearing is happening, you can land in undefined behavior. 😭💀 like, genuinely undefined. not cute.

so instead, we use a shadow buffer object approach. the glow-up plan is:

  1. swap the SA BO address with the shadow BO first 🔁
  2. perform the clearing operation on the BB 🧽
  3. update the shadow BO in the ring buffer 💫
  4. sync the shadow and the actual buffer so they stay consistent, because consistency is main character energy ✨

that's the whole choreography. no skipped steps, no shortcuts, periodt. 👑

✨ RETURN ✨

None. — nothing comes back. it simply does the thing and leaves. 🦋

✨ SEE ALSO ✨

go read these next, bestie, they're all in the kernel file ./drivers/gpu/drm/xe/xe_migrate.c:

like a whole friend group of migrate functions. obsessed. 🌈💜

ngl, the shadow BO dance exists specifically so you don't get that halted-mid-operation undefined behavior. treat it with respect, it's doing a lot of work for you. 🙈

and that's the page, diva 💅✨ — brought to you by ./drivers/gpu/drm/xe, dated October 2026, from the xe_migrate_c...w_copy_clear(9) manual. mwah, go clear some batch buffers responsibly. 🍓🎀🧚

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