Red Hat Bugzilla – Bug 1320066
Qemu should not report error when cmdline set threads=2 in Intel host
Last modified: 2017-03-21 05:37:24 EDT
Description of problem: In Intel host, when qemu cmdline set threads=2, without -cpu specified, report qemu-kvm: AMD CPU doesn't support hyperthreading. Please configure -smp options properly. Version-Release number of selected component (if applicable): 2.6.32-633.el6.x86_64 qemu-kvm-0.12.1.2-2.490.el6.x86_64 How reproducible: 100% Steps to Reproduce: 1.# /usr/libexec/qemu-kvm -name win10 -m 6G -smp 2,threads=2,cores=1,sockets=1 qemu-kvm: AMD CPU doesn't support hyperthreading. Please configure -smp options properly. VNC server running on `::1:5900' 2. 3. Actual results: report error: qemu-kvm: AMD CPU doesn't support hyperthreading. Please configure -smp options properly. Expected results: should not report this error Additional info: My machine: model name : Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz just happens without -cpu specified, if -cpu type is AMD, report this error, -cpu type is Intel ,didn't report retest qemu-kvm-0.12.1.2-2.483.el6.x86_64, no this issue,so this a Regression
Hi,Wei Seems this bug because fixed Bug 1292678 - Qemu should report error when cmdline set threads=2 in amd host , Can you check it? and on rhel7.2 no this issue. thanks Wei
I can reproduce this bug on Intel box. However I think this isn't a bug from the instrumentation I did with QEMU 6.8. Here are the findings: 1) The problem was introduced by commit 50d095912. The related code is in pc_new_cpu() of hw/pc.c file. 2) IS_INTEL_CPU(env) is TRUE, implying that QEMU believes guest is an AMD CPU. 3) I instrumented cpu_x86_register() of target-i386/cpuid.c file. When no -cpu is specified, cpu_model name is "cpu64-rhel6". So by default qemu-kvm-6.8 uses "cpu64-rhel6" as the CPU model when nothing is specified. According to target-i386/cpuid.c, "cpu64-rhel6" is based on AMD CPU model. From the data collected above, I think this warning msg is legit because AMD CPU doesn't support HyperThreading. -Wei
Is it a common usage case not to specify "-cpu"? I am trying to understand how annoying this warning message is.
(In reply to Wei Huang from comment #5) > Is it a common usage case not to specify "-cpu"? I am trying to understand > how annoying this warning message is. Hi Wei, I personally think it's no common scenario. However, 2 concerns. 1. Seems this is regression issue according to comment0 2. It's strange that the qemu-kvm promotes message like "AMD CPU doesn't support ..." but the qemu runs on Intel host. Best Regards, Junyi
Created attachment 1140266 [details] patch
This issue is indeed a regression. I have created a patch to fix the problem.
Fix included in qemu-kvm-0.12.1.2-2.495.el6
Reproduce proceduce Host version: kernel-2.6.32-642.el6.x86_64 qemu-kvm-0.12.1.2-2.490.el6.x86_64 Steps to Reproduce: 1./usr/libexec/qemu-kvm -name win10 -m 6G -smp 2,threads=2,cores=1,sockets=1 qemu-kvm: AMD CPU doesn't support hyperthreading. Please configure -smp options properly. VNC server running on `::1:5900' Actual results: report error: qemu-kvm: AMD CPU doesn't support hyperthreading. Please configure -smp options properly. ------------------------------------------- Verify this bug Host version: kernel-2.6.32-642.el6.x86_64 qemu-kvm-0.12.1.2-2.495.el6.x86_64 Test steps: 1./usr/libexec/qemu-kvm -name win10 -m 6G -smp 2,threads=2,cores=1,sockets=1 VNC server running on `::1:5900' Test results: not report this error. Conclusion： According to result above,this bug has been fixed. Additional info: My machine: model name : Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHSA-2017-0621.html