#426 regression: output garbled when booting FreeBSD

[Török Edwin]

I run qemu (from kvm-userspace) like this:
sudo /usr/local/bin/qemu-system-x86_64 -hda /var/local/emulators/freebsd/freebsd.img -m 512m -snapshot -monitor stdio

It boots, however the VGA screen is garbled: http://img245.imageshack.us/img245/7214/snapshot2.png
Same happens if I boot using -curses.

kvm-80 is last version that works OK, kvm-81 has garbled output, and so does the latest kvm-84.

I bisected this down to this commit:
9f24c509365a322b8f763b58246ec7841507ad7e is first bad commit
commit 9f24c509365a322b8f763b58246ec7841507ad7e
Author: pbrook <pbrook>
Date: Mon Dec 1 18:59:50 2008 +0000

Change MMIO callbacks to use offsets, not absolute addresses.

Signed-off-by: Paul Brook <paul@codesourcery.com>

:040000 040000 77d5ccafbc898b9f23add9d5af792f19b3bd7c99 f23cfaffa61efb36aa46dfeb771ad33cbfd4f3aa M qemu

Here is my bisect log:

bad: [18b8d7e31fda064559e5ddb06e6dd3a2ff21cca0] kvm: libkvm: check for slot overlap using 64-bit arithmetic

good: [5acca148670897e9ad43f175665c3550d3de03a3] kvm: qemu: Fix -no-kvm-irqchip

git bisect start 'kvm-81' 'kvm-80' '--' 'qemu'

bad: [dbfc099daa953a41a3572a7b8d72f75cc23604f1] Merge branch 'qemu-cvs'

git bisect bad dbfc099daa953a41a3572a7b8d72f75cc23604f1

good: [3ab7f6a7ca59860371940fffc87b4e157b4cb45c] kvm: qemu: fix compile failure in acpi.c

git bisect good 3ab7f6a7ca59860371940fffc87b4e157b4cb45c

bad: [ecdc204126f76d9608b9b1c113dbba21aaab5107] Virtio core support

git bisect bad ecdc204126f76d9608b9b1c113dbba21aaab5107

bad: [83f9f366c0f10183efc65628cda9ebe0ef9a784b] Cosmetic cleanups to previous patch.

git bisect bad 83f9f366c0f10183efc65628cda9ebe0ef9a784b

good: [733072ba55773483f3006473184deb1c0e91be5c] Use libgcc __clear_cache to clean icache, when available.

git bisect good 733072ba55773483f3006473184deb1c0e91be5c

good: [4297d2e1e432ddd06960a5390a1bf2d593f1ac29] arm: Don't potentially overwrite input registers in add2, sub2.

git bisect good 4297d2e1e432ddd06960a5390a1bf2d593f1ac29

bad: [9f24c509365a322b8f763b58246ec7841507ad7e] Change MMIO callbacks to use offsets, not absolute addresses.

git bisect bad 9f24c509365a322b8f763b58246ec7841507ad7e

good: [b16b3e63376d9142d11b539995cd3811f44e6366] Allocate cleared memory for cpu state.

git bisect good b16b3e63376d9142d11b539995cd3811f44e6366

I tried reverting this commit on top of kvm-84, however it doesn't revert cleanly.

System information:
CPU: Intel(R) Core(TM)2 Quad CPU Q9550 @ 2.83GHz
KVM version:kvm-84
host kernel: Linux debian 2.6.29.1 #54 SMP PREEMPT Tue Apr 7 12:09:25 EEST 2009 x86_64 GNU/Linux
host arch: x86_64
guest: FreeBSD 7.0-RELEASE, x86-64
qemu command-line: /usr/local/bin/qemu-system-x86_64 -hda /var/local/emulators/freebsd/freebsd.img -m 512m -snapshot -monitor stdio

The problem doesn't occur with -no-kvm.