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#436 -vga vmware + X-windows: display errors, jumpy mouse, hangs

open
nobody
intel (43)
5
2012-10-09
2009-05-13
No

With -vga vmware, Xorg (in the guest) doesn't display properly. The display is vaguely legible, but it's scrambled. With -vga vmware -smp 2, I get the same display problem, plus the mouse jumps erratically and kvm hangs.

CPU: Core 2 Duo P8600
KVM: kvm-85 (Gentoo ebuild kvm-85-r1, ncurses enabled, sdl enabled, all other USE flags disabled)
Host kernel: 2.6.29 (linux-2.6.29-gentoo-r3)
Host kernel arch: x86_64
Host distro: Gentoo AMD64
Guest kernel: 2.6.29 (linux-2.6.29-gentoo-r3), no virtio, no KVM_GUEST
Guest kernel arch: x86_64
Guest distro: Gentoo AMD64
Command line: kvm -kernel vmlinuz -append root=/dev/hda -hda /dev/mapper/vg0-linroot -vga vmware
Command line (alternate): kvm -smp 2 -kernel vmlinuz -append root=/dev/hda -hda /dev/mapper/vg0-linroot -vga vmware

Here's a more detailed description of the problem:

I'm trying to run Xorg on a Gentoo guest. With kvm -vga std and the vesa X driver, everything works fine, even with -smp 2. With kvm -vga vmware and the vmware X driver, though, the X display is scrambled. I can barely see some garbled twm xterm windows (see attached screenshot), and I can type in those xterms. I tried different resolutions and HorizSync/VertRefresh's, but it's always scrambled.

If I use kvm -vga vmware -smp 2, the display is similarly scrambled, and additionally the mouse is unusable. If I move the mouse, the guest pointer starts jumping all over erratically. Sometimes the pointer settles down and stops (until I touch the mouse again), sometimes it keeps jumping around. Xorg usually outputs a bunch of "[mi] EQ overflowing. The server is probably stuck in an infinite loop." errors while this is happening.

If I keep moving the mouse, kvm eventually hangs: I can't ungrab the pointer from the kvm window, so I have to switch to VT1; top shows that kvm is using max CPU; kvm doesn't respond to SIGINT; and I have to kill -9 kvm. The amount of mouse waving it takes to hang kvm varies (~5s-120s), and it's only reproducible ~20% of the time. If the guest kernel has any paravirtualization, though, the hang happens much faster and is 100% reproducible.

Discussion

  • Balzac von Jigglypuff

    Screenshot of Xorg

     
  • Balzac von Jigglypuff

    GDB stack trace of hung kvm

     
  • Balzac von Jigglypuff

    Xorg server configuration

     
  • Balzac von Jigglypuff

    -no-kvm-pit doesn't change anything.

    With -no-kvm or -no-kvm-irqchip, the display is still garbled, but I don't get mouse jitters and hangs with -smp 2.

     
  • Jes Sorensen

    Jes Sorensen - 2010-11-26

    Sounds like a problem with the vmware vga emulation in QEMU. Do you still see these problems with recent versions of KVM/QEMU?

    Thanks,
    Jes

     

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