Red Hat Bugzilla – Bug 618332
CPUID_EXT_POPCNT enabled in qemu64 and qemu32 built-in models.
Last modified: 2014-07-24 23:46:00 EDT
Description of problem: Upstream qemu commit 910628f39676ee65211727245809eec7ca4d75f5 adds POPCNT to qemu64/qemu32. This can break migration when using these guest models should migration be attempted to a cpu lacking this feature. How reproducible: # /usr/libexec/qemu-kvm -cpu ?dump Actual results: x86 [qemu64] QEMU Virtual CPU version 0.12.1 : feature_ecx 00802001 (popcnt cx16 pni|sse3) x86 [qemu32] QEMU Virtual CPU version 0.12.1 : feature_ecx 00800001 (popcnt pni|sse3) Expected results: "popcnt" should not be present. Additional info: The addition of popcnt to what is intended as a least common denominator seems rather odd, as only select CPUs support this feature. This was specifically enabled by the commit called out above and understanding what motivated this change needs to be part of the case resolution.
This issue has been proposed when we are only considering blocker issues in the current Red Hat Enterprise Linux release. ** If you would still like this issue considered for the current release, ask your support representative to file as a blocker on your behalf. Otherwise ask that it be considered for the next Red Hat Enterprise Linux release. **
Not just popcnt, the other flags should be reviewed against hardware in the field.
Tested with qemu-kvm-0.12.1.2-2.108.el6, 1. # /usr/libexec/qemu-kvm -cpu ?dump x86 cpu64-rhel5 QEMU Virtual CPU version (cpu64-rhel5) : feature_ecx 00000001 (pni|sse3) : x86 cpu64-rhel6 QEMU Virtual CPU version (cpu64-rhel6) : feature_ecx 00002001 (cx16 pni|sse3) : 2. Boot guest with -M rhel6.0.0 & -M rhel5.5.0 & -M rhel5.4.4 & -M rhel5.4.0, guest can be boot up successfully with related cpu model. cmd: # /usr/libexec/qemu-kvm -m 4G -smp 2 -monitor stdio -drive file=/home/RHEL-Server-6.0-64-virtio.qcow2,if=none,format=qcow2,boot=on,cache=none,id=test -device virtio-blk-pci,drive=test -device virtio-net-pci,mac=20:20:20:12:23:15,netdev=hostnet0 -netdev tap,script=/etc/qemu-ifup,vhost=on,id=hostnet0 -usbdevice tablet -vnc :10 -M xxxx Based on above, change status to verified.
Red Hat Enterprise Linux 6.0 is now available and should resolve the problem described in this bug report. This report is therefore being closed with a resolution of CURRENTRELEASE. You may reopen this bug report if the solution does not work for you.