[Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
This affected me. Took me several days. The solution posted by asd fghjkl (ryzen27) worked for me as well: sudo nano /etc/modprobe.d/kvm.conf options kvm ignore_msrs=1 and then rebooted I'm very glad i found this thread. Don't know where to report this or if it's even a bug, But hope it gets fixed! -- 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: Expired 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
[Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
I was able to avoid rebooting after following @Andrii's instructions - https://bugs.launchpad.net/qemu/+bug/1703506/comments/19 - above: systemctl stop libvirtd libvirtd-admin.socket libvirtd-ro.socket libvirtd.socket sudo modprobe -r kvm_intel kvm systemctl start libvirtd libvirtd-admin.socket libvirtd-ro.socket libvirtd.socket These instructions to avoid rebooting might not work for those using a non-Intel CPU as you'll have a different kernel module. You can check by running `lsmod | grep kvm`. Cheers, ak. System info: # inxi -CMz Machine: Type: Laptop System: Dell product: Precision M6700 v: 01 serial: Mobo: Dell model: 0JWMFY v: A00 serial: UEFI: Dell v: A20 date: 11/30/2018 CPU: Info: quad core model: Intel Core i7-3840QM bits: 64 type: MT MCP cache: L2: 1024 KiB Speed (MHz): avg: 3607 min/max: 1200/3800 cores: 1: 3588 2: 3615 3: 3638 4: 3588 5: 3588 6: 3638 7: 3617 8: 3588 -- 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: Expired 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
[Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
Found the same problem using Gnome boxes, as I understand it uses QEMU. Error I see in gnome boxes when I'm trying to install windows 10 vm: SYSTEM THREAD EXCEPTION NOT HANDLED Fresh install of Ubuntu 22.04 CPU: AMD Ryzen 7 1700 The solution posted by asd fghjkl (ryzen27) worked for me too: sudo nano /etc/modprobe.d/kvm.conf add "options kvm ignore_msrs=1" (without quotes) reboot -- 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: Expired 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
[Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
[Expired for QEMU because there has been no activity for 60 days.] ** Changed in: qemu Status: Incomplete => Expired -- 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: Expired 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
[Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
** Bug watch removed: Red Hat Bugzilla #1135772 https://bugzilla.redhat.com/show_bug.cgi?id=1135772 ** Bug watch removed: Red Hat Bugzilla #1592276 https://bugzilla.redhat.com/show_bug.cgi?id=1592276 ** Changed in: qemu Assignee: Eduardo Habkost (ehabkost) => (unassigned) -- 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: Incomplete 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
[Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
The QEMU project is currently considering to move its bug tracking to another system. For this we need to know which bugs are still valid and which could be closed already. Thus we are setting older bugs to "Incomplete" now. If you still think this bug report here is valid, then please switch the state back to "New" within the next 60 days, otherwise this report will be marked as "Expired". Or mark it as "Fix Released" if the problem has been solved with a newer version of QEMU already. Thank you and sorry for the inconvenience. ** Changed in: qemu Status: New => Incomplete -- 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: Incomplete 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
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
@ryzen27: do you have dmesg logs showing the MSRs being written by the guest? You may be hitting the bug described at https://bugzilla.redhat.com/show_bug.cgi?id=1592276 ** Bug watch added: Red Hat Bugzilla #1592276 https://bugzilla.redhat.com/show_bug.cgi?id=1592276 -- 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
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
I got it to work: sudo nano /etc/modprobe.d/kvm.conf add "options kvm ignore_msrs=1" (without quotes) reboot Then changing "-machine q35" to "-machine pc" kept it from crashing randomly. -- 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
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
QEMU 3.0 has limited TOPOEXT support. You can try using `-cpu EPYC`, and the `threads` option is supposed to work. -- 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
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
Error I see in terminal: AMD CPU doesn't support hyperthreading. Please configure -smp options properly. Error I see in my windows 10 vm: SYSTEM THREAD EXCEPTION NOT HANDLED I am unable to use Qemu at all. Serious problem. CPU: AMD Ryzen 5 1600X Six-Core Processor × 6 -- 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
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
I tried the above patches on a TR 1900X and they do not help to enable SMT. I still receive the warning. Also, with the patches applied, the CPU now identifies as EPYC in the guest. -- 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
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
just to be clear.. The kernel kvm patch is rebased on linux-next. If you are on older kernel then try this kernel patch. https://patchwork.kernel.org/patch/10031775/ plus qemu patch. -- 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
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
Posted few patches to support this feature on AMD EPYC processors. Feel free to test and review. 1. Kernel kvm patch https://patchwork.kernel.org/patch/10190107/ 2. qemu patches https://patchwork.kernel.org/project/qemu-devel/list/?submitter=178527 Thanks -- 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
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
The core topology info used by Linux (see linux/arch/x86/kernel/cpu/amd.c:amd_get_topology()) is actually at CPUID[0x801e]. AMD's documentation is a bit confusing, as the Architecture Programmer's Manual still refers to CPUID[0x801e].EBX[bits 7:0] as "compute unit ID", but the Processor Programming Reference for AMD Family 17h documents the same bits as "Core ID". We can implement CPUID[0x801e] and print the existing warning only if CPU vendor is AMD and cpuid_family != 0x17. -- 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
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
I am looking at the diff between the host and guest CPUID, and we have a few candidates: CPUID[4] is all zeroes on the host, and the host has CPUID leaves up to 0x801f available, including CPUID[0x801d] (which contains cache topology information). Probably we need to implement CPUID[0x801d], I will take a look at Linux code to find out if that's all we need. Full CPUID diff below: --- /tmp/host-x86info.txt 2017-07-25 15:01:26.753304233 -0300 +++ /tmp/guest-x86info.txt 2017-07-25 15:01:33.563335744 -0300 @@ -1,29 +1,29 @@ eax in: 0x, eax = 000d ebx = 68747541 ecx = 444d4163 edx = 69746e65 -eax in: 0x0001, eax = 00800f11 ebx = 00100800 ecx = 7ed8320b edx = 178bfbff -eax in: 0x0002, eax = ebx = ecx = edx = +eax in: 0x0001, eax = 00800f11 ebx = 00080800 ecx = ffd83203 edx = 178bfbff +eax in: 0x0002, eax = 0001 ebx = ecx = 004d edx = 002c307d eax in: 0x0003, eax = ebx = ecx = edx = -eax in: 0x0004, eax = ebx = ecx = edx = -eax in: 0x0005, eax = 0040 ebx = 0040 ecx = 0003 edx = -eax in: 0x0006, eax = 0004 ebx = ecx = 0001 edx = -eax in: 0x0007, eax = ebx = 209c01a9 ecx = edx = +eax in: 0x0004, eax = 0c000121 ebx = 01c0003f ecx = 003f edx = 0001 +eax in: 0x0005, eax = ebx = ecx = 0003 edx = +eax in: 0x0006, eax = 0004 ebx = ecx = edx = +eax in: 0x0007, eax = ebx = 209c01ab ecx = edx = eax in: 0x0008, eax = ebx = ecx = edx = eax in: 0x0009, eax = ebx = ecx = edx = eax in: 0x000a, eax = ebx = ecx = edx = -eax in: 0x000b, eax = ebx = ecx = edx = +eax in: 0x000b, eax = 0001 ebx = 0002 ecx = 0100 edx = eax in: 0x000c, eax = ebx = ecx = edx = eax in: 0x000d, eax = 0007 ebx = 0340 ecx = 0340 edx = -eax in: 0x8000, eax = 801f ebx = 68747541 ecx = 444d4163 edx = 69746e65 -eax in: 0x8001, eax = 00800f11 ebx = 2000 ecx = 35c233ff edx = 2fd3fbff +eax in: 0x8000, eax = 801a ebx = 68747541 ecx = 444d4163 edx = 69746e65 +eax in: 0x8001, eax = 00800f11 ebx = ecx = 03f3 edx = 2fd3fbff eax in: 0x8002, eax = 20444d41 ebx = 657a7952 ecx = 2037206e edx = 30303731 eax in: 0x8003, eax = 67694520 ebx = 432d7468 ecx = 2065726f edx = 636f7250 eax in: 0x8004, eax = 6f737365 ebx = 20202072 ecx = 20202020 edx = 00202020 -eax in: 0x8005, eax = ff40ff40 ebx = ff40ff40 ecx = 20080140 edx = 40040140 -eax in: 0x8006, eax = 26006400 ebx = 66006400 ecx = 02006140 edx = 00808140 -eax in: 0x8007, eax = ebx = 001b ecx = edx = 6599 -eax in: 0x8008, eax = 3030 ebx = 0007 ecx = 400f edx = +eax in: 0x8005, eax = 01ff01ff ebx = 01ff01ff ecx = 40020140 edx = 40020140 +eax in: 0x8006, eax = ebx = 42004200 ecx = 02008140 edx = 00808140 +eax in: 0x8007, eax = ebx = ecx = edx = +eax in: 0x8008, eax = 3028 ebx = ecx = 0007 edx = eax in: 0x8009, eax = ebx = ecx = edx = -eax in: 0x800a, eax = 0001 ebx = 8000 ecx = edx = 0001bcff +eax in: 0x800a, eax = ebx = ecx = edx = eax in: 0x800b, eax = ebx = ecx = edx = eax in: 0x800c, eax = ebx = ecx = edx = eax in: 0x800d, eax = ebx = ecx = edx = @@ -38,10 +38,5 @@ eax in: 0x8016, eax = ebx = ecx = edx = eax in: 0x8017, eax = ebx = ecx = edx = eax in: 0x8018, eax = ebx = ecx = edx = -eax in: 0x8019, eax = f040f040 ebx = ecx = edx = -eax in: 0x801a, eax = 0003 ebx = ecx = edx = -eax in: 0x801b, eax = 03ff ebx = ecx = edx = -eax in: 0x801c, eax = ebx = ecx = edx = -eax in: 0x801d, eax = 4121 ebx = 01c0003f ecx = 003f edx = -eax in: 0x801e, eax = ebx = 0100 ecx = edx = -eax in: 0x801f, eax = 0007 ebx = 016f ecx = 000f edx = +eax in: 0x8019, eax = ebx = ecx = edx = +eax in: 0x801a, eax = ebx = ecx = edx = -- You received this bug notification because
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
I tried disabling the CmpLegacy bit directly on /target/i386/cpu.c deleting the If statement on "case 0x8001:" or changing "*ecx |= 1 << 1;" to "*ecx |= 0 << 1;" But it didn't work, the VM still sees 8 physical cores. I believe the HTT bit should be enabled by default I tried changing it to "*edx |= 1 << 28;" in the If statement of "case 1:" just in case but it didn't matter. Anything else that I could try to hard-code for testing? -- 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
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
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
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
Thank you for the info. Having info on Linux guests' behavior would be nice to have, but it's possible to extract the raw CPUID data seen by the Windows guest using an equivalent Windows tool (suggestions of tools are welcome). Also, can somebody confirm if the same Windows version works as expected on bare metal? -- 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
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
I can confirm the same behavior with a Ryzen 7 1700. Host Arch Linux x64 Kernel 4.11.9, Guest Windows 10 Pro. Running with -cpu host and -smp 8,sockets=1,cores=4,threads=2. Attached the logs of the host and results of the output of msinfo32 and "WMIC CPU Get NumberOfCores,NumberOfLogicalProcessors /Format:List" in the guest. Same results as scix, in my case 8 Core(s), 8 Logical Processors(s). This seems relevant: https://bugzilla.redhat.com/show_bug.cgi?id=1135772 And a few extra reports on reddit: https://www.reddit.com/r/VFIO/comments/6nuhb5/big_problem_with_my_ryzen_1700x/ https://www.reddit.com/r/VFIO/comments/6m6kry/smthyperthreading_support_with_ryzen_cpu_and/ I'll test with a Linux guest later. ** Bug watch added: Red Hat Bugzilla #1135772 https://bugzilla.redhat.com/show_bug.cgi?id=1135772 ** Attachment added: "smt-ryzen.zip" https://bugs.launchpad.net/qemu/+bug/1703506/+attachment/4917550/+files/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
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
>Please confirm what's the QEMU command-line being used (especially the -smp and -cpu options), and check if the bug persists if using "-cpu host". I'm using -cpu host already, here's just the cpu and smp commands: -cpu host,hv_vendor_id=whatever,kvm=off,hv_relaxed,hv_spinlocks=0x1fff,hv_vapic,hv_time,smep=off -smp 12,sockets=1,cores=6,threads=2 The extra commands are just for VGA passthrough, but the problem still occurs with just -cpu host (plus smep=off, problems with booting with it enabled) and the above smp setting. I've attached host output; I'm using a Windows guest and running msinfo32 indicates: AMD Ryzen 1600 Six-Core Processor, 3693 Mhz, 12 Core(s), 12 Logical Processors(s) Suggesting that the guest is seeing the host as 12 cores, 1 thread each, rather than 6 cores, 2 threads each. If Linux guest information would be more helpful, I'll set up a Linux guest as well. ** Attachment added: "Host logs" https://bugs.launchpad.net/qemu/+bug/1703506/+attachment/4917236/+files/qemu-ryzen-smt-logs.tar.gz -- 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
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
** Changed in: qemu Assignee: (unassigned) => Eduardo Habkost (ehabkost) -- 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
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
The warning doesn't make QEMU disable anything, it just warns the user that guests are likely to ignore the HT info on CPUID if CPU vendor is AMD. Please confirm what's the QEMU command-line being used (especially the -smp and -cpu options), and check if the bug persists if using "-cpu host". To help find out what's wrong, I'd like to see /proc/cpuinfo, "lscpu -e" output and "x86info -v -a" output from both the host system and the guest system. -- 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
[Qemu-devel] [Bug 1703506] Re: SMT not supported by QEMU on AMD Ryzen CPU
I can confirm this problem as it affects me, too on Ubuntu XENIAL, Kernel 4.10.0-26-generic -- 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
