Re: [Qemu-devel] [PATCH 0/2] target-i386: "custom" CPU model + script to dump existing CPU models

[Paolo Bonzini]

On 24/06/2015 17:58, Eduardo Habkost wrote:
> > 3) regarding "enforce", there are indeed some cases where it would break:
> > 
> > - Haswell/Broadwell CPU model after TSX removal
> > 
> > - qemu64 with KVM
> > 
> > - pretty much everything including qemu64 with TCG
> 
> - Everything involving KVM CPUID features, that change depending on the
>   kernel version.
> 
> - Intel CPU models that had VMX enabled in older machine-types,
>   and may or may not have VMX enabled depending on kernel VMX nesting
>   configuration.
> 
> > So libvirt here could allow _now_ the user to specify enforce, either
> > via XML or via qemu.conf (or via XML + a default specified via qemu.conf).
> 
> More precisely, libvirt would emulate "enforce" mode by checking the
> "filtered-features", because "enforce" error messages are not
> machine-friendly.

Even better, because it would let libvirt special-case stuff like TSX,
VMX and SVM.

Paolo