Hyper-V Not Working

Earthwalker

Member
Jul 14, 2020
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Hello,

Got a DELL PowerEdge R740XD server with Xeon Gold 6271C CPUs, which I try to setup Hyper-V on VM but failed.

If I enable -hypervisor, Hyper-V install succeed and Windows reboot works, but we can't start VM in Hyper-V, event log says hypervisor not started.

I have enabled nested virtualization in host, install Proxmox on VM and install Windows on top of that works.

Software settings I have tested:

1. Fresh installed Proxmox, newest version.
2. Tried Windows 10 (1809, 1909, 2004), Windows Server (2016, 2019), Windows Hyper-V Server 2019.
3. Tried OVMF and SeaBIOS.
4. For CPU module, tried host, KVM and others.
5. For machine type, tried both q35 and i440fx.
6. For -cpu arguments, tried -hypervisor,kvm=off,+vmx and many of these hv arguments.

Can Hyper-V works inside of Proxmox VM?

Thanks.
 

Earthwalker

Member
Jul 14, 2020
6
0
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After change CPU from host to Cascadelake-Server, Hyper-V works!

However, got these message after start VM:

Code:
kvm: warning: host doesn't support requested feature: CPUID.07H:EBX.hle [bit 4]
kvm: warning: host doesn't support requested feature: CPUID.07H:EBX.rtm [bit 11]
kvm: warning: host doesn't support requested feature: MSR(48FH).vmx-exit-load-perf-global-ctrl [bit 12]
kvm: warning: host doesn't support requested feature: MSR(490H).vmx-entry-load-perf-global-ctrl [bit 13]
kvm: Host doesn't support requested features
start failed: QEMU exited with code 1

Need remove "enforce" from cpu argument in order for VM to boot.
 

Earthwalker

Member
Jul 14, 2020
6
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I have spent more than a week on this issue and got it working finally. The key setting is add "-mpx" to cpu arguments.

Here are some key info.

CPU flags of the host (running Proxmox):

Code:
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb cat_l3 cdp_l3 invpcid_single intel_ppin ssbd mba ibrs ibpb stibp ibrs_enhanced tpr_shadow vnmi flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid cqm mpx rdt_a avx512f avx512dq rdseed adx smap clflushopt clwb intel_pt avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local dtherm ida arat pln pts pku ospke avx512_vnni md_clear flush_l1d arch_capabilities

CPU flags of a guest VM with CPU set to "host" (running Proxmox):

Code:
flags        : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon rep_good nopl xtopology cpuid tsc_known_freq pni pclmulqdq vmx ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch cpuid_fault invpcid_single ssbd ibrs ibpb stibp ibrs_enhanced tpr_shadow vnmi flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid mpx avx512f avx512dq rdseed adx smap clflushopt clwb avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves arat umip pku ospke avx512_vnni md_clear arch_capabilities

CPU flags of a guest VM with CPU set to "Cascadelake-Server" (running Proxmox):

Code:
flags        : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx pdpe1gb rdtscp lm constant_tsc rep_good nopl xtopology cpuid tsc_known_freq pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch cpuid_fault invpcid_single pti ssbd ibrs ibpb fsgsbase bmi1 avx2 smep bmi2 erms invpcid avx512f avx512dq rdseed adx smap clflushopt clwb avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 arat pku ospke avx512_vnni

1. Compare host with guest (CPU "host"):

Host only flags:
Code:
dts acpi tm pbe art pebs bts nonstop_tsc aperfmperf dtes64 monitor ds_cpl smx est tm2 sdbg xtpr pdcm dca epb cat_l3 cdp_l3 intel_ppin mba cqm rdt_a intel_pt cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local dtherm ida pln pts flush_l1d

Guest only flags:
Code:
tsc_known_freq hypervisor umip

2. Compare guest (CPU "host") with guest (CPU "Cascadelake-Server"):

Guest (CPU "host") only flags:
Code:
ss arch_perfmon vmx stibp ibrs_enhanced tpr_shadow vnmi flexpriority ept vpid ept_ad tsc_adjust mpx xsaves umip md_clear arch_capabilities

Guest (CPU "Cascadelake-Server") only flags:
Code:
pti

Some tips:

1. Get a list of supported processer architectures: qemu-system-x86_64 -cpu ?
2. Get VM starup commans: qm showcmd VM-ID --pretty
 

Earthwalker

Member
Jul 14, 2020
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Here are my setup status:

CPU: Intel Xeon Gold 6271C x 2
File system: ZFS
System: Windows 10 (2004)

VM configs:

Code:
args: -cpu host,hv_ipi,hv_relaxed,hv_reset,hv_runtime,hv_spinlocks=0x1fff,hv_stimer,hv_synic,hv_time,hv_vapic,hv_vpindex,+kvm_pv_eoi,+kvm_pv_unhalt,+vmx,-hypervisor,-mpx
balloon: 0
bios: ovmf
bootdisk: sata0
cores: 32
cpu: host
efidisk0: local-zfs:vm-100-disk-1,size=1M
machine: q35
memory: 32768
name: Win10-2004
net0: virtio=AAAAAAAAAAAAA,bridge=vmbr0,firewall=1
numa: 1
ostype: win10
sata0: local-zfs:vm-100-disk-0,cache=writeback,discard=on,size=60G,ssd=1
scsihw: virtio-scsi-pci
smbios1: uuid=AAAAAAAAAAAAAAAAA
sockets: 2
vmgenid: AAAAAAAAAAAAAAAAAAAAAAA

Hyper-V is working but Windows UI are laggy. Is there anyway to improve speed of nested Windows?
 

Andros

Member
Jan 19, 2020
4
0
6
47
have some troubles with Xeon Gold 6140 x2
HyperV works , but VMs inside HyperV cant start

adding this strigs in <vm>.conf solve promlem (but i dont undestand what means this args ))) where are i can find manuals ?)
args: -cpu host,hv_ipi,hv_relaxed,hv_reset,hv_runtime,hv_spinlocks=0x1fff,hv_stimer,hv_synic,hv_time,hv_vapic,hv_vpindex,+kvm_pv_eoi,+kvm_pv_unhalt,+vmx,-hypervisor,-mpx
cpu: host,flags=+hv-evmcs
 

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