Add VMware absolute-pointer backdoor (port 0x5658)#1542
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SuperMaxusa
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Apr 11, 2026
Owner
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Nice work, thanks. This breaks mouse movement when the mouse is locked. We should probably have at least one of these, preferably both:
Oh, and updating the documentation how to install the driver on old Windows versions would be nice. I tested on Arch and it works out of the box. |
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Author
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Sounds good, thanks for the feedback - I'll add it! Give me a week or so |
Implements GETVERSION + ABSPOINTER_{COMMAND,STATUS,DATA} so a guest
driver (VBADOS VBMOUSE, vmwmouse, Linux vmmouse) can read the host
cursor position and track it 1:1 without pointer lock.
The queue is fed by the existing mouse-absolute bus event that
MouseAdapter already emits; PS/2 still supplies IRQ12 (the driver reads
this port on each mouse IRQ). Move-only packets are coalesced in place
so the guest never falls more than one packet behind regardless of how
slowly it drains. Emits vmware-absolute-mouse on the bus when the guest
toggles absolute mode so the embedder can drop pointer lock and hide the
host cursor.
State save/restore covers the enabled/absolute flags.
DEBUG builds assert on unregistered IO widths; some guests probe 0x5658 with IN AX,DX during detection. Answer 8/16-bit reads as an empty port and ignore writes. The |0 on the ABSPOINTER subcommand case labels was sign-coercion to match Int32Array reads, but all four constants fit in 31 bits so it was a no-op.
- Don't lock the pointer on screen click while the guest uses absolute positioning, and release an existing lock when the guest driver enables absolute mode - While the pointer is locked (e.g. for games), report movement as relative packets instead of absolute positions, since no meaningful absolute position exists under pointer lock - Document VMware Tools mouse driver installation for Windows 9x and 2000/XP
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SuperMaxusa
reviewed
Jun 1, 2026
Owner
|
Nice contribution, thanks! |
Owner
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Small follow-up: 7919dfb |
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Implements GETVERSION + ABSPOINTER_{COMMAND,STATUS,DATA} so a guest driver (VBADOS VBMOUSE, vmwmouse, Linux vmmouse) can read the host cursor position and track it 1:1 without pointer lock.
The queue is fed by the existing mouse-absolute bus event that MouseAdapter already emits; PS/2 still supplies IRQ12 (the driver reads this port on each mouse IRQ). Move-only packets are coalesced in place so the guest never falls more than one packet behind regardless of how slowly it drains. Emits vmware-absolute-mouse on the bus when the guest toggles absolute mode so the embedder can drop pointer lock and hide the host cursor.
In practice, this is what it looks like on Windows 95:
cursor.mov