Bug Description:
Encountering a boot failure when launching a KVM guest with
'qemu-system-ppc64'. The guest hangs at boot, and the QEMU monitor
crashes.
Reproduction Steps:
# qemu-system-ppc64 --version
QEMU emulator version 9.2.50 (v9.2.0-2799-g0462a32b4f)
Copyright (c) 2003-2025 Fabrice Bellard and the QEMU Project developers
# /usr/bin/qemu-system-ppc64 -name avocado-vt-vm1 -machine
pseries,accel=kvm \
-m 32768 -smp 32,sockets=1,cores=32,threads=1 -nographic \
-device virtio-scsi-pci,id=scsi \
-drive
file=/home/kvmci/tests/data/avocado-vt/images/rhel8.0devel-ppc64le.qcow2,if=none,id=drive0,format=qcow2
\
-device scsi-hd,drive=drive0,bus=scsi.0 \
-netdev bridge,id=net0,br=virbr0 \
-device virtio-net-pci,netdev=net0 \
-serial pty \
-device virtio-balloon-pci \
-cpu host
QEMU 9.2.50 monitor - type 'help' for more information
char device redirected to /dev/pts/2 (label serial0)
(qemu)
(qemu) qemu-system-ppc64: warning: kernel_irqchip allowed but
unavailable: IRQ_XIVE capability must be present for KVM
Falling back to kernel-irqchip=off
** Qemu Hang
(In another ssh session)
# screen /dev/pts/2
Preparing to boot Linux version 6.10.4-200.fc40.ppc64le
(mockbuild@c23cc4e677614c34bb22d54eeea4dc1f) (gcc (GCC) 14.2.1 20240801
(Red Hat 14.2.1-1), GNU ld version 2.41-37.fc40) #1 SMP Sun Aug 11
15:20:17 UTC 2024
Detected machine type: 0000000000000101
command line:
BOOT_IMAGE=(ieee1275/disk,msdos2)/vmlinuz-6.10.4-200.fc40.ppc64le
root=/dev/mapper/fedora-root ro rd.lvm.lv=fedora/root crashkernel=1024M
Max number of cores passed to firmware: 2048 (NR_CPUS = 2048)
Calling ibm,client-architecture-support... done
memory layout at init:
memory_limit : 0000000000000000 (16 MB aligned)
alloc_bottom : 0000000008200000
alloc_top : 0000000030000000
alloc_top_hi : 0000000800000000
rmo_top : 0000000030000000
ram_top : 0000000800000000
instantiating rtas at 0x000000002fff0000... done
prom_hold_cpus: skipped
copying OF device tree...
Building dt strings...
Building dt structure...
Device tree strings 0x0000000008210000 -> 0x0000000008210bd0
Device tree struct 0x0000000008220000 -> 0x0000000008230000
Quiescing Open Firmware ...
Booting Linux via __start() @ 0x0000000000440000 ...
** Guest Console Hang
Git Bisect:
Performing git bisect points to the following patch:
# git bisect bad
e8291ec16da80566c121c68d9112be458954d90b is the first bad commit
commit e8291ec16da80566c121c68d9112be458954d90b (HEAD)
Author: Nicholas Piggin <npig...@gmail.com>
Date: Thu Dec 19 13:40:31 2024 +1000
target/ppc: fix timebase register reset state
(H)DEC and PURR get reset before icount does, which causes them to
be
skewed and not match the init state. This can cause replay to not
match the recorded trace exactly. For DEC and HDEC this is usually
not
noticable since they tend to get programmed before affecting the
target machine. PURR has been observed to cause replay bugs when
running Linux.
Fix this by resetting using a time of 0.
Message-ID: <20241219034035.1826173-2-npig...@gmail.com>
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
hw/ppc/ppc.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
Reverting the patch helps boot the guest.
Thanks,
Misbah Anjum N
