virt-install-5 enable hyperv features for Windows Guest by default

What happen: virt-install creating Windows VM fail after update system fedora-41

Starting install... 
ERROR unsupported configuration: host doesn't support hyperv 'vpindex' feature
ERROR unsupported configuration: host doesn't support hyperv 'vpindex' feature

why

virt-install version update from 4.x to 5.0. and in new virt-install-5.0, it enables the hyperv features when creating Windows VM. but I used the option –qemu-commandline=”-cpu host,+svm” it overwrite the -cpu option that generated by virt-install+virsh …

workaround or resolution

There is also a –cpu option for virt-install, using –cpu=host,+svm instead –qemu-commandline=”-cpu host,+svm” fixed the issue.
So generally don’t use the –qemu-commandline= option unless you know what you are doing.

about hyperv features

[EN] KVM on x86 implements Hyper-V Enlightenments for Windows guests. These features make Windows and Hyper-V guests think they’re running on top of a Hyper-V compatible hypervisor and use Hyper-V specific features.

[ZH] KVM 在 x86上为 Windows Guest 实现了 HyperV Enlightenment，这些特性会让 Windows 和其他 HyperV 的 Guest 认为他们运行在 HyperV 兼容的 Hypervisor 上，这样Guest就会自动开启一些半虚拟化的性能优化。

see also:

• Hyper-V Enlightenments
• KVM中的HperV增强
• 优化 Windows 虚拟机