vmw_msg_ioctl(9)

💌 vmw_msg_ioctl(9) — like, the kernel API manual, but make it make sense

okay bestie, welcome to vmw_msg_ioctl(9), from the Kernel API Manual ✨ this one is genuinely tiny but it's got main character energy in the vmwgfx world, so let's get into it 🫶

This is the page for vmw_msg_ioctl — the function that yeets a message from user-space over to the host, and (plot twist) can also catch a result coming back from the host and hand it to user-space 💅

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✨ NAME ✨

vmw_msg_ioctl — sends and receives a message to/from host from/to user-space 🎀

(yes it's that whole two-way situation, we love a bidirectional icon)

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🌸 SYNOPSIS 🌸

int vmw_msg_ioctl (struct drm_device *dev , void *data , struct drm_file
*file_priv );

That's the whole signature, no cap — three args, one int coming back at you 💖

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🦋 ARGUMENTS 🦋

• dev — identifies the drm device. this is your "which one are we even talking about" argument 👑
• data — pointer to the ioctl argument. literally the payload, the whole point of the trip ✨
• file_priv — identifies the caller. like, who's asking? it's giving caller ID 🎀

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💜 DESCRIPTION 💜

So what does it do? Two things, and they're lowkey iconic:

Sends a message from user-space to host. 🚀

Can also receive a result from host and return that to user-space. 📥

That's it. That's the function. outbound message, optional inbound result, done. no notes, periodt 💅

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🔥 RETURN 🔥

• Zero on success 🌈 (the good ending)
• negative error code on error 💀 (the "something went sideways" ending)

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🧚 SEE ALSO 🧚

the kernel file ./drivers/gpu/drm/vmwgfx/vmwgfx_msg.c plus a whole friend group of related functions — go say hi:

• vmw_open_channel(9)
• vmw_close_channel(9)
• vmw_port_hb_out(9)
• vmw_port_hb_in(9)
• vmw_send_msg(9)
• vmw_recv_msg(9)
• vmw_host_get_guestinfo(9)
• vmw_host_printf(9)
• reset_ppn_array(9)
• hypervisor_ppn_reset_all(9)
• hypervisor_ppn_add(9)
• hypervisor_ppn_remove(9)
• mksstat_init_record_time(9)
• mksstat_init_kern_id(9)
• vmw_mksstat_get_kern_slot(9)
• vmw_mksstat_cleanup_descriptor(9)
• vmw_mksstat_remove_all(9)
• vmw_mksstat_reset_ioctl(9)
• vmw_mksstat_add_ioctl(9)
• vmw_mksstat_remove_ioctl(9)
• vmw_disable_backdoor(9)

like, a whole squad 😭🫶

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and that's the page! 🎀 it lives in ./drivers/gpu/drm/vmwgfx, it's dated October 2026, and the whole thing is filed under vmw_msg_ioctl(9) — go forth and ioctl responsibly bestie 💖✨🌸