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Kernel: Process available VMWare mouse events immediately

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The Qemu I8042 controller does not send one IRQ per event, it sends
over four since it will not stop trying to emulate the PS/2 mouse.

If the VMWare backdoor is active, a fake I8042 mouse event will be sent
that we can then use to check if there are VMWare mouse events present.
However, we were only processing one mouse event at a time, even though
multiple events could have been queued up. Luckily this does not often
lead to issues, since after the first IRQ we would still get three
additional interrupts that would then empty the queue.

This change makes sure we always empty the event queue immediately,
instead of waiting on the next interrupt to happen. Functionally this
changes nothing - it could merely improve latency by not waiting for
new interrupts to come in.

Coincidently, this brings our implementation closer to how Linux deals
with the VMMouse.
This commit is contained in:
Jelle Raaijmakers 2021-11-04 15:34:26 +01:00 • committed by Andreas Kling
parent 8a65a9c30f
commit a4b1c0fd0c
3 changed files with 30 additions and 19 deletions
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14
Kernel/Devices/VMWareBackdoor.cpp
View file

@ -183,22 +183,26 @@ void VMWareBackdoor::send(VMWareCommand& command)
command.dx);
}
Optional<MousePacket> VMWareBackdoor::receive_mouse_packet()
u16 VMWareBackdoor::read_mouse_status_queue_size()
{
VMWareCommand command;
command.bx = 0;
command.command = VMMOUSE_STATUS;
send(command);
if (command.ax == 0xFFFF0000) {
dbgln_if(PS2MOUSE_DEBUG, "PS2MouseDevice: Resetting VMWare mouse");
disable_absolute_vmmouse();
enable_absolute_vmmouse();
return {};
return 0;
}
int words = command.ax & 0xFFFF;
if (!words || words % 4)
return {};
return command.ax & 0xFFFF;
}
MousePacket VMWareBackdoor::receive_mouse_packet()
{
VMWareCommand command;
command.size = 4;
command.command = VMMOUSE_DATA;
send(command);