** Description changed: + [Impact] + + * The qemu code prior to qemu 3.0 has an issue where the power9 machine + spec makes the guest issue unsupported instructions. Qemu has to be + adapted to be able to understand that and not break. + + * backport of upstream fix https://git.qemu.org/?p=qemu.git;a=commitdiff;h=c8fd8373e42821984400382cd91b8bf4e7c14e3b + + [Test Case] + + * Run a guest in P9 mode, on guest init it will hang - with the fix it + will reach a login prompt. + + Feel free to use the provided initrd to boot from. + Any host Bionic+ kernel seems to do, so we are just reusing the hosts + vmlinuz. + + $ wget https://openpower.xyz/job/initramfs/job/buildroot-master/lastSuccessfulBuild/artifact/rootfs-le.cpio.xz + $ qemu-system-ppc64 -nographic -vga none -M pseries,cap-htm=off -cpu POWER9 -m 1G -kernel /boot/vmlinux-$(uname -r) -initrd rootfs-le.cpio.xz + + + [Regression Potential] + + * The change is very limited to just the PPC eieio instruction, so if any + it can only affect that. Also the new type is only part of the P9 spec, + so any guest running in older modes won't be affected either. + Those guests that would be affected by a potentially bad emulation + error in the new code are those that didn't work at all so far - + therefore it might contain a but but should not regress something + working today. + Only if there would be "another" eieio instruction source out there + with bit 6 set (I know of none) that code would be able to regress + those cases. + + [Other Info] + + * n/a + + ---- + == Comment: #0 - Murilo Opsfelder Araujo <muri...@br.ibm.com> - 2018-08-15 15:08:52 == ---Problem Description--- qemu 1:2.11+dfsg-1ubuntu7.4 hangs when -cpu POWER9 is specified. Bisecting qemu, I found this patch: https://git.qemu.org/?p=qemu.git;a=commitdiff;h=c8fd8373e42821984400382cd91b8bf4e7c14e3b With a small tweak, it applies on qemu 2.11.1 from bionic and fixes the hang. - This was originally reported as a kernel bug at https://github.com/linuxppc/linux/issues/168 - - Contact Information = Murilo Opsfelder Araujo <muri...@linux.ibm.com> - + This was originally reported as a kernel bug at + https://github.com/linuxppc/linux/issues/168 + + Contact Information = Murilo Opsfelder Araujo <muri...@linux.ibm.com> + ---uname output--- Linux jaspion1 4.15.0-30-generic #32-Ubuntu SMP Thu Jul 26 17:43:11 UTC 2018 ppc64le ppc64le ppc64le GNU/Linux - - Machine Type = na - + + Machine Type = na + ---Debugger--- A debugger is not configured - + ---Steps to Reproduce--- - wget https://openpower.xyz/job/initramfs/job/buildroot-master/lastSuccessfulBuild/artifact/rootfs-le.cpio.xz + wget https://openpower.xyz/job/initramfs/job/buildroot-master/lastSuccessfulBuild/artifact/rootfs-le.cpio.xz - qemu-system-ppc64 -nographic -vga none -M pseries,cap-htm=off -cpu POWER9 -m 1G -kernel /boot/vmlinux-$(uname -r) -initrd rootfs-le.cpio.xz - - Userspace tool common name: qemu - - The userspace tool has the following bit modes: 64-bit + qemu-system-ppc64 -nographic -vga none -M pseries,cap-htm=off -cpu + POWER9 -m 1G -kernel /boot/vmlinux-$(uname -r) -initrd rootfs-le.cpio.xz + + Userspace tool common name: qemu + + The userspace tool has the following bit modes: 64-bit Userspace rpm: qemu - Userspace tool obtained from project website: na - + Userspace tool obtained from project website: na + *Additional Instructions for Murilo Opsfelder Araujo <muri...@linux.ibm.com>: -Attach ltrace and strace of userspace application. == Comment: #1 - Murilo Opsfelder Araujo <muri...@br.ibm.com> - 2018-08-15 15:26:53 == I'll provide a debdiff.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1787408 Title: qemu 1:2.11+dfsg-1ubuntu7.4 hangs when -cpu POWER9 is specified To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1787408/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
