Attached Ubuntu 17.04 guest logs. I wasn't able to run x86info as root. Only as regular user. Error shown: readEntry: Operation not permitted error reading 1KB from 0x3fffc00
There are a few bug reports about it but no workarounds. Seems to happen on vm's. So the output is missing a few sections. >Also, can somebody confirm if the same Windows version works as expected on bare metal? Yes, same Windows version on bare metal works as expected. In my case showing 8 cores and 16 threads/logical processors. I'm trying to use 4 cores 8 threads in the VMs. Both Windows and Ubuntu are showing 8 physical cores. ** Attachment added: "ubuntu-guest-smt-ryzen.zip" https://bugs.launchpad.net/qemu/+bug/1703506/+attachment/4917874/+files/ubuntu-guest-smt-ryzen.zip -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1703506 Title: SMT not supported by QEMU on AMD Ryzen CPU Status in QEMU: New Bug description: HyperThreading/SMT is supported by AMD Ryzen CPUs but results in this message when setting the topology to threads=2: qemu-system-x86_64: AMD CPU doesn't support hyperthreading. Please configure -smp options properly. Checking in a Windows 10 guest reveals that SMT is not enabled, and from what I understand, QEMU converts the topology from threads to cores internally on AMD CPUs. This appears to cause performance problems in the guest perhaps because programs are assuming that these threads are actual cores. Software: Linux 4.12, qemu 2.9.0 host with KVM enabled, Windows 10 pro guest To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1703506/+subscriptions