Hi, Qemu-system-ppc built from current master can no longer run Fedora 12 ppc as guest. (This the only ppc distro I tested.) Host is Fedora 34. Please see screen shot attached. Booting from both an installation DVD and from an installed system fail. To reproduce: compile qemu-system-ppc from current master and run: ./qemu-system-ppc \ -M mac99,via=pmu \ -m 1024 \ -L pc-bios \ -boot d \ -cdrom Fedora-12-ppc-DVD.iso \ -g 1024x768x8 I tracked the issue down to this commit: 8f0a4b6a9b40e18116a2bb6bbcc00feb8119c792 is the first bad commit commit 8f0a4b6a9b40e18116a2bb6bbcc00feb8119c792 Author: Matheus Ferst Date: Tue Jun 1 16:35:28 2021 -0300 target/ppc: Move cmp/cmpi/cmpl/cmpli to decodetree Additionally, REQUIRE_64BIT when L=1 to match what is specified in The Programming Environments Manual: "For 32-bit implementations, the L field must be cleared, otherwise the instruction form is invalid." Some CPUs are known to deviate from this specification by ignoring the L bit [1]. The stricter behavior, however, can help users that test software with qemu, making it more likely to detect bugs that would otherwise be silent. If deemed necessary, a future patch can adapt this behavior based on the specific CPU model. [1] The 601 manual is the only one I've found that explicitly states that the L bit is ignored, but we also observe this behavior in a 7447A v1.2. Signed-off-by: Matheus Ferst Message-Id: <20210601193528.2533031-15-matheus.ferst@eldorado.org.br> Reviewed-by: Richard Henderson [dwg: Corrected whitespace error] Signed-off-by: David Gibson target/ppc/insn32.decode | 14 ++++++++ target/ppc/translate.c | 52 ------------------------------ target/ppc/translate/fixedpoint-impl.c.inc | 31 ++++++++++++++++++ 3 files changed, 45 insertions(+), 52 deletions(-) Best, Howard [image: Qemu-system-ppc-Fedora-Crashing.png]