Am 13.11.25 um 11:53 PM schrieb Thomas Lamprecht: > On Fri, 07 Nov 2025 15:43:38 +0100, Fiona Ebner wrote: >> Changes in v2 (thanks Dano and Thomas!): >> * Pass running CPU configuration when using 'nested-virt'. This >> ensures that migration fails early if the flag resolves differently >> on the target. >> * Describe that live migration still only works if it's the same flag. >> * Drop adding non-existing link in API end point. >> * Keep $supported_cpu_flags private to module and add getter method. >> * Unpack @_ first at the beginning of resolve_cpu_flags(). >> * ui: fix function call in the CPU flag selector widget. >> * ui: use simpler method to get all records of the store. >> * Drop already applied patches. >> >> [...] > > Applied the first three qemu-server patches already, thanks! > > For the nested-flag I'm not fully sure yet if this is enough also for Windows > guests to run e.g. WSL with a non-host CPU type like x86-64-v3, which I might > not put into scope originally, but for many users it will IMO be assumed as > "has to work" if we put this in the changelog.
Thanks to Mario for directing my attention to the related bugzilla entry [0] earlier today! What seems to be necessary is setting the base model to something matching the vendor of the host CPU "cpu: EPYC,flags=+nested-virt" resulting in EPYC,enforce,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,+svm,vendor=AuthenticAMD on the QEMU commandline. Well, I still got an error later: PS C:\Windows\system32> wsl -d archlinux wsl: Nested virtualization is not supported on this machine. but I also got a bash and could issue commands. FWIW, I got the same error and behavior when using "host" CPU model. I couldn't get it to work with CPU type qemu64, even with all of: qemu64,+abm,+aes,+avx,+avx2,+bmi1,+bmi2,enforce,+f16c,+fma,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,+movbe,+pni,+popcnt,+sse4.1,+sse4.2,+ssse3,+xsave,+svm,hv_emsr_bitmap,hv_syndbg,hv_tlbflush,hv_tlbflush_direct,hv_tlbflush_ext,hv_xmm_input, kvm=off,vendor=AuthenticAMD,hv-passthrough Should we add a hint in the UI (if OS type is Windows) that the 'nested-virt' flag may require a base model matching the vendor of the host CPU? [0]: https://bugzilla.proxmox.com/show_bug.cgi?id=7021 _______________________________________________ pve-devel mailing list [email protected] https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel
