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ni / nilrt

Tools to build NI Linux RT distribution.
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Improve graphical support in QEMU start script #248

Closed mike-petersen-ni closed 1 year ago

mike-petersen-ni commented 1 year ago

As noted in AB#2503092, a segmentation fault is currently encountered when attempting to run NILRT in a QEMU VM with ui.enabled=True. This occurs in X, using the /usr/lib/xorg/modules/input/vmmouse_drv.so library, in the function VMMouseProtoInOut; it is written in assembly and attempts to interact with an IO port with an inl %dx, %eax instruction.

The qemu(1) manpage has this text describing its -machine options:

vmport=on|off|auto
Enables emulation of VMWare IO port, for vmmouse etc. auto says to select the value based on accel. For accel=xen the default is off otherwise the default is on.

I haven't investigated why the vmmouse driver fails. Since disabling that port prevents the issue, it may be a QEMU bug with emulating that port.

Debugging info for reference

- QEMU version: 8.1.1 - opkg packages installed for debugging: - `gdb` - `xf86-input-vmmouse-{dbg,dev,src}` - `xinit-{dbg,dev,src}` - `xserver-xorg-{dbg,dev,src}` - GDB script used to chase down the segfault: ``` set history file ~/X.gdb-log set history save on file /usr/bin/X add-symbol-file /usr/lib/xorg/modules/input/vmmouse_drv.so set directories /usr/src/debug/xserver-xorg/2_21.1.8-r0/xorg-server-21.1.8 /usr/src/debug/xf86-input-vmmouse/2_13.1.0-r0/xf86-input-vmmouse-13.1.0/src start :0 b main.c:246 b xf86Init.c:745 # b udev.c:452 # ignore 4 10 # b udev.c:291 b xf86Xinput.c:968 b vmmouse_client.c:66 ``` - GDB backtrace: ``` #0 0x00007f289a77636b in VMMouseProtoInOut (cmd=0x5b529b) at ../../xf86-input-vmmouse-13.1.0/shared/vmmouse_proto.c:66 #1 VMMouseProto_SendCmd (cmd=0x5b529b) at ../../xf86-input-vmmouse-13.1.0/shared/vmmouse_proto.c:150 #2 0x00000000005a6548 in ?? () #3 0x00007f289a776192 in VMMouseClientVMCheck () at ../../xf86-input-vmmouse-13.1.0/shared/vmmouse_client.c:66 #4 VMMouseClient_Enable () at ../../xf86-input-vmmouse-13.1.0/shared/vmmouse_client.c:152 #5 0x00007f289a775ea5 in VMMousePreInit (drv=, pInfo=0x17a7470, flags=) at ../../xf86-input-vmmouse-13.1.0/src/vmmouse.c:430 #6 0x0000000000545990 in xf86NewInputDevice (pInfo=0x17a7470, pdev=pdev@entry=0x7ffe4a16e0e8, enable=) at ../xorg-server-21.1.8/hw/xfree86/common/xf86Xinput.c:968 #7 0x00000000005468f6 in NewInputDeviceRequest (options=0x17a5b80, attrs=attrs@entry=0x7ffe4a16e0f0, pdev=pdev@entry=0x7ffe4a16e0e8) at ../xorg-server-21.1.8/hw/xfree86/common/xf86Xinput.c:1118 #8 0x00000000005943ca in device_added (udev_device=udev_device@entry=0x17e5580) at ../xorg-server-21.1.8/config/udev.c:291 #9 0x000000000059486b in config_udev_init () at ../xorg-server-21.1.8/config/udev.c:452 #10 0x0000000000593799 in config_init () at ../xorg-server-21.1.8/config/config.c:50 #11 0x0000000000539ae1 in InitInput (argc=argc@entry=2, argv=argv@entry=0x7ffe4a16e3f8) at ../xorg-server-21.1.8/hw/xfree86/common/xf86Init.c:745 #12 0x0000000000466d5d in dix_main (argc=2, argv=0x7ffe4a16e3f8, envp=) at ../xorg-server-21.1.8/dix/main.c:246 #13 0x00007f289aef057b in __libc_start_call_main (main=main@entry=0x42b350

, argc=argc@entry=2, argv=argv@entry=0x7ffe4a16e3f8) at ../sysdeps/nptl/libc_start_call_main.h:58 #14 0x00007f289aef0630 in __libc_start_main_impl (main=0x42b350
, argc=2, argv=0x7ffe4a16e3f8, init=, fini=, rtld_fini=, stack_end=0x7ffe4a16e3e8) at ../csu/libc-start.c:389 #15 0x000000000042b385 in _start () at ../sysdeps/x86_64/start.S:115 ```

Besides disabling that vmport, this PR also adds an option to the script as a shortcut for adding arguments to better support graphical usage.

mike-petersen-ni commented 1 year ago

v2