@ThoriumBR Most OSes that detect that they're running virtualized are just using CPUID which, for KVM, is the string KVMKVMKVM (see elixir.bootlin.com/linux/v5.16/source/arch/x86/include/uapi/asm/… and elixir.bootlin.com/linux/v5.16/source/arch/x86/kvm/cpuid.c#L909). This can be spoofed easily. If there's an application or driver on Windows that's attempting more advanced hypervisor detection, then it'll be very difficult.

The Linux kernel documentation explains how KVM handles CPUID here: kernel.org/doc/html/latest/virt/kvm/x86/cpuid.html

I'm sure there's a way to manually change the CPUID vendor identification string in QEMU.